This is a really interesting question, and one that a lot of animal owners have been asking. There are also different views by vets – on a quick “straw poll” in our office, we have had three different answers so far! Ultimately, it boils down to questions of effectiveness, safety, cost and convenience – but in this blog we are going to try and use evidence to determine what the best solution is in the real world.
What is the lepto vaccine for?
As the name suggests, the vaccine provides limited, but fairly effective, protection against Leptospira infection. This is caused by a group of bacteria called leptospires that are spread in the urine of infected animals, primarily rats. The bacteria can infect many animals, including dogs, cattle and humans, and may lead to liver damage, kidney failure, and are potentially fatal, with UK vets reporting a 60% mortality rate in infected dogs.
That said, clinical infection is relatively uncommon, possibly as a result of relatively widespread vaccination – while the vaccine does not prevent infection with leptospires, it is pretty good at preventing that infection from causing clinical disease, and excellent at preventing the patient from becoming a carrier, infecting other dogs, animals or people.
What’s the difference between the two vaccines?
The main difference is that the L2 contains only 2 strains of leptospire – Icterohaemorrhagiaeand Canicola. Historically these were the most common types seen – however, in recent years others have been increasingly being seen and in the L4, the manufacturers made two changes – firstly, they increased the amount of antigenic compound (i.e. how many dead bacteria were present), and secondly they added two additional strains, Australis(the group containing the specific strain Bratislava) and Grippotyphosa (reported to be the most common strain in much of Europe). Contrary to popular belief, there has been no change in the adjuvant component of the vaccine between the two versions.
Why are some puppies being started on L2 anyway?
Originally, the manufacturers of the L4 series of vaccines (Intervet, a subsidiary of Merck’s MSD Animal Health division) had intended to phase out the L2 vaccine, and entirely replace it with L4.
However, there has been a widely publicised campaign reporting large numbers of deaths and other harmful effects from the vaccine, and a lot of breeders refuse to use it; as a result, many vets offer either the L4 or the L2.
Is the L4 vaccine really dangerous?
It depends how you define your terms! Ultimately, any medication is potentially dangerous – a drug that never has any side effects at all is, sadly, either a myth or a product that doesn’t do anything at all. As soon as you start altering or tweaking the physiology of an organism as complex as a mammal, there is the potential for unexpected and undesirable results. In actual fact, vaccines as a whole are much safer than most medicines, because they are actually far more natural than any pharmaceutical or herbal medicine.
We need to remember what a vaccine is – essentially, it’s not intended to alter the animal’s physiology or biochemistry. Instead, we can think of it as being like a flight simulator – it allows the immune system to “practice” how to fight an infection, with a lower (or in the case of a killed vaccine like Lepto, zero) risk of real infection. However, there is always the chance of the immune system “overreacting”. As a result, both the manufacturers and the regulators are required to keep data as to how many suspected adverse reactions occur.
For L2, the risk is 0.015% of a suspected adverse reaction – so of 10,000 dogs given the vaccine, we would expect 2 to become ill enough to require treatment, and therefore get a report of a significant side effect. For L4, the risk ishigher, at 0.069% (so 7 in 10,000). This is a similar risk to you developing anaphylactic shock, an asthma attack, or a bleed on the brain after taking an aspirin tablet– it can happen, but it probably won’t.
What about all the dogs who are supposed to have died?
Hundreds of thousands of doses of L4 are given every year – sadly, sooner or later statistically some dogs will develop more serious problems, some of which may be fatal. The trouble is that a “suspected adverse reaction” may or may not actually be due to the vaccine – it could be that the patient developed some disease at a similar time, that it was due to some other component in the combination vaccine given, or (most commonly of all) that the dog was examined by a vet who noticed the problem at the time of vaccination.
That said, there is a very real possibility that any vaccine can trigger an autoimmune disease. Is this really a vaccine related event? The consensus of opinion is that these dogs would sooner or later experience autoimmune disease, as they were genetically predisposed to do so – either triggered by a vaccine, or by a natural infection, it wouldn’t really matter.
Overall, though, dogs having L4 are roughly 4 ½ times more likely to become unwell than dogs having L2.
So, is it worth it?
Now here’s the rub! Unfortunately, there is no central database for how many Leptospirosis cases there are in the UK that are due to each serotype of the bacteria. We are pretty sure that Grippotyphosais not natively found in the UK (although this would be relevant to any dogs visiting Europe). However, in 1991 a major study was conducted in Edinburgh and Glasgow and found that just over 6% of dogs had been exposed to Bratislava (part of the Australis group) – and of those dogs testing positive for exposure to any Lepto strain, 5% were actively excreting Bratislava bacteria.
Assuming a 5% risk of infection at any one time, this means that 1 in 20 (500 in 10,000) of the L2 but not L4 vaccinated dogs poses a risk to others of spreading Leptospira bacteria; assuming that 98% of cases are subclinical, then 0.1% (10 in 10,000) will get ill – a rather higher number than the risk of suspected adverse reactions.
So overall, based on the evidence we have now, yes, you are better off vaccinating against L4 than just limiting it to L2.
How do we move forward?
There are three options –
- Get them upgraded now. This will, however, cost more and be inconvenient, for a relatively small benefit to your dog.
- Don’t upgrade, just keep them on L2. This is cheapest and most convenient, but does mean that there’s a substantial risk that they will be shedding the bacteria, and there is still a markedly increased risk of harm.
- Upgrade when your dog is next due their vaccination. This is probably the best “compromise” position.
Overall, it’s really important that you and your vet agree a vaccination plan for your dog as an individual. Also, don’t trust online scaremongering – there are lots of very misleading websites out there (mainly anti-vaccination, but some over-enthusiastically pro-vaccine as well) whose output is based entirely on emotion and illogic, rather than evidence and clinical reality.
You may also be interested in;
- Dog Vaccinations: are they really necessary?
- Do dogs need parvo vaccines?
- What vaccines does my dog really need?
- Can I give painkillers to my dog?
- What is the DHPP Vaccine for Dogs?
For any health concerns, please also use our free Dog Symptom Checker.
Discussion
One of my dogs developed acute kidney injury a year ago, thought to be due to Leptospirosis, despite being vaccinated with L2. I was told at the time that there had been an increase in cases due to the wet weather. There’s 2 comments I’d like to make. Firstly, although it didn’t protect her, I am so glad that she was up to date with her vaccinations because at least I couldn’t blame myself for it. Secondly, I will always wonder if she would have been better protected if she’d have had the L4. My other dog has now had the L4. As for Bella, after a week in the vets she recovered, but unfortunately developed Osteosarcoma a few months after, and I lost her in May.
Hi our new dog was given lepto4 when with the breeder and our vet has given him the lepto2 booster. Does that mean he is only vaccinated effectively for lepto2?
Yes, essentially.
My puppy I took home at 8 weeks he had his 1st lepto 2 and dhp vaccination. When I took him to my vet he gave him dhp and kennel cough vaccinations without my permission at 10 weeks they were both vet 4 pets then be ause I dint give permission for the kennel cough I took him to another vets 4 pets that the told me all his jabs so far are basically useless and he has to start a new batch of lepto 4. She gave him 1 then and there and they say he has to have another in 4 weeks, by then he will be 4 months old without even having a walk, surely this is wrong why has he have to have all these vaccinations and not allowed out til 4 months old
I think that’s something you’d have to take up with the first practice – certainly, the should never give any medication without consent, although I think it’s most likely that there was a misunderstanding as to why the puppy was presented to them (for example, if you booked in specifically for a vaccine appointment, then it would be reasonable for them to assume you wanted standard vaccinations).
In terms of when he can go out, that will depend on the specific risk factors where you are, and what locations are high vs low risk. That’s something to talk to your new practice about; however, it is true that the protection won’t be sufficient until about a week after the second vaccine, which has to be 4 weeks after the first.
So interested in this discussion. Our two year old lab had been given lepto 2 when we picked him up, and ended up getting lepto 4 at our own vets and having a second dose 4 weeks later. When we picked up our beagle puppy this time, we checked which vaccines the breeders vet used (lepto 2 again) and opted to get our puppy vaccinated ourselves. Unfortunately our puppy had a seizure within 24 hours on his lepto 4. He’s had a whole host of tests, all clear, and it’s been put down as a vaccine reaction. For his second set of jags our vet is switching to lepto 2 (like others mentioned we’re covering the cost of the whole box) and he’ll get another 4 weeks later. My plan to not have my puppy in the house an extra 4 weeks has failed, but I’m grateful he’s fine, and for the care and attention he’s received. Incidentally, my vet reported to manufacturers, and has not had a response so far!
Hmmm… The manufacturers are usually pretty good, if in doubt, you can report directly to the regulator as well: https://www.vmd.defra.gov.uk/adversereactionreporting/report-type
My dog had both L2 vaccines by 12 weeks and before I collected her. She has had her second dose today of L4 and the receptionist at the vets told me I can’t take her out for a week. She is now nearly 5 months. I said I didn’t get told that on her first L4 vaccine. Should I keep her in for the next week?
It’s a balance of risk. She won’t have full protection from Lepto for another week to 10 days; however, she will have protection from 2 of the 3 strains present in the UK from the L2.
I am totally confused, I recently got a 5mth old cocker spaniel, he had his puppy vacs Canigen Lepto 2 and there DHPPi as required and all good – I took him to my usual vet this week and took his vacs record card along and was told at 12mths he would need his vacs again has they use differnt vaccines – I asked was this because puppy had Lepto 2 and not 4 and was told yes and just the booster was not sufficient.
Why can’t they just give him what he had and get Canigen for him. Are there some brands out there that are not compatable.
There are very few genuinely non-compatible vaccines, as far as we know. However, using different brands to boost is strictly off-license use, and that’s not allowed unless the vet believes there is no other clinical option.
The L2/L4 issue is more complex. The L4 vaccine will PROBABLY boost the L2 components effectively, but will definitely not generate a decent immune response against the two newer serovars in the vaccine, and that’s probably what your vet is worried about.
Well I really liked reading it. This subject offered by you is very practical for good planning.
Are nobivac vaccines real vaccines and is my dog safe to play with others if they have all nobivac?
Yes, they’re very reputable and probably the most widely used brand here in the UK. Definitely real and definitely effective!
Our vet gave our puppy a different brand of L4 for his second injection does that affect him. They want to give him a third injection of the correct brand
IHAVE bred cockers for many years. The Leptos vax is a comparatively new addition to the annual booster requirement. Personally I cannot see the need for this vax since the incidents of infection and risk from my investigations is very low. I have heard that the frequency and severity of reaction to particularly L4 is
Becoming a problem. I have held concerns for many years with the annual requirement for the three usually required when instruction fir their use are that a booster is required every three years . Because of occasional need to board my dogs in kennels I find that I am made to give the annual booster shot and now they are insisting on Leptos vax too ! Where is my choice? It also maizes me that vets and kennels are unaware that boosters are no longer required after seven years ? It is obvious that over vax has indeed caused a specific problem now,
The Kennel Club agree there is an issue , but nothing appears to happen as a result. I understand the necessity for vets to earn a living , but the additional cost suddenly imposed, simply by walking through the door! Which adds £40/£60 to the cost of any further treatment, with dogs being handed to rescue at an alarming rate and the state of the country so dire, how was this mammoth increase implemented without it seemed, any consultations? I am 78 yr old and my experience with dogs and vets is long, I have witnessed a dreadful decrease in care over these years particularly since the take over of most vets practices by large corporations ! Which explained the sudden charges imposed indeed? Thanks for listening, my concerns are for the welfare of the dog! If Leptos was a raging problem in the U.K., then I could understand the need. As a result of my own intensive research, I would prefer to be allowed to make my own choses in this regard wrong. There is presently a petition sent to the Vet Association which I recently signed , it is becoming a issue of great concern to many breeders and owners.
I think there are several overlapping issues in your post here, so let’s start at the top.
Leptospirosis is a massively underdiagnosed condition, and we genuinely don’t know how many cases there are per year, at least partly because the majority of dogs with suspected Lepto are euthanased without confirmatory testing (which is difficult and expensive). However, leptospira vaccines are hardly new, they’ve been around for over 20 years – which probably explains the relatively low incidence of confirmed cases (people who don’t vaccinate are less likely to pay for testing). It’s like measles in humans – it’s rare because so many people are vaccinated, when vaccine coverage drops, cases rise.
The L4 vaccine was introduced because new strains of Lepto have (probably as a result of pet travel across Europe) now arrived in the UK. They aren’t rare either, as studies on feral dogs show. However, as the VMD data makes clear, there is indeed an increased risk of side effects – but these are almost invariably mild and self limiting (unlike Leptospirosis, for example). I have never yet seen a dog develop anything worse than a sore lump and a day or two off colour (just like us when we have our vaccines!).
Regarding the “7 years” thing, yes it’s true that the DHP components of the routine vaccines usually last longer than the 3 years the vaccine is licensed for (note, not annually as you claim – vaccinating against DHP annually is really rare, less than 5% of vets do this because no-one thinks its necessary). However, after 7 years, approximately 60% of dogs retain immunity to all three components – fine for them, but what about the other 40%? If you don’t want to vaccinate that often with the core components, that’s fine – but PLEASE do a titre test to confirm that your dog is one of the ones who is still immune! Of course, that costs money too – and the tests themselves are fairly expensive. That said, a titre test doesn’t work for leptospirosis, and the immune memory is short after infection (about 6 months) and vaccination (about 9-15 months, at best).
Regarding the costs – yes, medical inflation is very high. Inevitably, veterinary inflation runs in parallel. However, I can assure you that the vets you see have your dogs’ best interests at heart. They may of course be wrong (although the evidence does not support this), but very few vets in the UK nowadays are on commission – most of us get a flat salary independent of what we prescribe.
Corporatisation of the veterinary sector is a concern – but unfortunately current law does not allow the RCVS, the regulator, to regulate practices or companies, only individual vets and nurses. So my suggestion would be to write to your MP, and sign or set up a petition to the government to introduce a new Veterinary Surgeons Act to make sure that the companies themselves were regulated, rather than just us footsoldiers!!!
Probably not – in fact, it might even be slightly more effective. However, it is “off license” because there is no testing done to check whether the same vaccines from different manufacturers boost each other properly.
There are studies showing some Vaccines to be completely incompatible with one another. I’m also a vet.
By “completely incompatible” what do you mean? Failure of immunity at V1 and V2, or when combined in the same programme at the same time – or even in the same syringe?
As far as I know, none of these studies relate to Leptospira vaccines, as they are all multi-antigen bacterin products containing a massive array of epitopes.
My cocker spaniel puppy had Canigen DHP and Canigen Lepto 4 at 8 weeks and the. Nobivac DHP and Nobivac L4 at 12 weeks. How long after these second jabs can I take her out and socialise with other dogs?
It depends to some extent on the local risk factors where you are – but here in the UK, especially if you’re in an urban area, the risk of Lepto is fairly high. Most vets would advise 2 weeks after the second vaccine, to give time for a good immune response; however, have a chat with your vet and see if their local guidance is different, as we all have different risk profiles depending on where we are!
That said, don’t miss out on socialisation – try to find a safe indoor space where she can meet lots of (vaccinated) dogs in a safe way – puppy parties are great for this!
I have recently changed vets to a new town. My dogs are 2,6,9 and 10 years old. They previously were given L4 but my new vet only does L2. Do they need to start a new course of two vaccines, two weeks apart or is their previous cover enough that just a booster of L2 would be required? I can understand it would be for upgrade from L2 to L4 – but is this necessary when downgrading to L2?
Not normally no – in general, a single booster of L2 can follow an L4 primary course.
Hello there i would really appreciate your advice.
We are getting a new puppy and the breeder will be getting the first vaccination for her.
She will be getting the L4.
I phoned the vet i am going to be using to book in for second vaccination and they told me 4 weeks after the first dose they would administer the 2nd dose.
However…. The vet that is doing the first dose has said they will administer the 2nd dose after just 2 weeks.
Is there any right or wrong here? Is it just vets preferences?
Different brands of the vaccines have different wait periods – although they are as far as I’m aware intercompatible. However, for most of the L4s it is 4 weeks, L2 is usually 2 weeks – so do double check it is L4 she had first time!
David, not all brands of vaccine are compatible. Where are you getting this information. For example; vanguard is not compatible with nobivac or canigen.
By “not compatible” all that is meant is that there have been no studies to demonstrate effective boosting with brand 2 after brand 1. It does not mean that they have been trialled and found ineffective.
I’d refer to the WSAVA Guidelines – “60. May I use different vaccine brands (manufacturers) during the vaccination program? Yes. It may even be desirable to use vaccines from different manufacturers during the life of an animal, because different products may contain different strains (e.g. of feline calicivirus). However, it is not recommended to mix vaccines that contain different strains (e.g. FCV or Leptospira serogroups) during a primary vaccination programme.”
As long as the serogroups (or ideally specific serovars) match, then biologically there is little or no difference from the immunological perspective. When I’ve queried this with manufacturers in the past, they have invariably said they “have no data but it should work”.
Also, remember that Vanguard do not offer an L4 option – their vaccine only contains the serogroups Leptospira canicola and Leptospira icterohaemorrhagiae, the same as all the other manufacturers’.
However – if you are aware of any published studies demonstrating failure of immunity when different brands containing the same serogroups are used for V1 and V2, I’d be fascinated, and more than happy to change my advice!
My dog had a very bad reaction to this vaccination. Her quality of life was badly affected as was mine. I will never let another dog have Lepto 2 or Lepto 4
I’m very sorry to hear that. I must say though, that is very, very rare – I don’t think I’ve ever seen a severe reaction to either of the Lepto vaccines, but I have seen a number of dogs suffering, and mostly dying, from Lepto.
Collecting our puppy middle of January, at 9 weeks old. She is booked in for her 1st vaccination with the breeder which will be an Nobivac L2. We’re now registering with a local vets who use L4. Would it be best to get her L2 first, then start the L4 and booster with our vets, or not get the L2 and start with just the L4?
It’s probably best to use L4 followed by an L4 booster because that’s only two jabs not three – and she won’t have any significant protection (because it’s a killed vaccine) until after the second jab anyway. However, it will depend on the timescales!
My 12 week puppy has had her second Nobivac L4, vet has said wait 3 weeks before it is effective, I am reading conflicting advice and worried still not “out of home” until 15 weeks , any thoughts?
The manufacturer’s warrant the vaccine to have its full protective effect 3 weeks after the second dose (just like we see with the Covid vaccines in humans, if you think about it!). There will be some protection earlier… but it will be significantly less. At the end of the day, I think it’s worth waiting IF you can socialise her properly and take her out in your arms or a carrier, for example, to see the world.
Hello, I would be very grateful if you could clarify something for me.
I took my 10 yr old Cavapoo for his annual vaccination this morning and was advised that the practice is now recommending Nobivac4. This was given and I was told that he requires a booster vaccination in 4 weeks time. I subsequently realised that the appointment I arranged falls when we are away from home. I called the practice to ask for an appointment either the day before or two days after the original ( which would have been exactly 4 weeks later , practically to the hour )
I explained the circumstances to the receptionist who stated with obvious irritation that the vaccination HAS TO BE given PRECISELY 4 weeks after the first or it is ‘off license’ and may not be effective. Could you please advise me why this rather extreme timeframe is required . I could have made the appointment at any time during practice opening hours on the appointed day, which seems to indicate there is an 9 hour window only for the ‘guaranteed efficacy’ after the 4 week interval.
Thank you for your assistance.
I neved done the second one ,and L4 it is very dangerous
Actually, all the evidence says that it really isn’t – it’s certainly a lot less dangerous than Leptospirosis for most dogs!
The reason is that the manufacturer has only licensed the medication on this timeframe, and has no published data to demonstrate effectiveness with any other protocol or schedule. In reality, there is almost certainly some variability, although the bacterin vaccines (like Lepto) do tend to be pretty temperamental about the exact intervals between the initial doses. I’d have a chat with the vet rather than the receptionist, who’ll be more familiar with the specifics of this vaccine from this manufacturer. Often the manufacturers do have data on file for managing these situations, but it’s only available to the treating vet on request (which I agree is silly, but if they published it, they’d risk being made to pay for a new license…)
My 3 year old dog has had boosters of lepto 2 every year, he is due a booster soon for this year and my vet is now only giving lepto 4, will he need to start a new course of two vaccinations or will he just require the one dose ?
If he gets the Lepto 4 he can just have a single dose and that will boost the Lepto 2 components; however, for full protection (against the other two as well) he’ll need 2 doses.
My puppy will have had both lots of vaccines when we collect him, and the breeders vet only uses L2. We want to upgrade to L4, but how long after his second L2 injection should we wait?
Most people would recommend 6-12 months later, but I’m not aware of any rigid protocols on this and it will vary depending on the manufacturer.
We have a 9 week old Minature Schnauzer we picked her up last week from the breeder she came vaccinated with Nobivac Lepto 2. I have an appointment with our vets next week to have her 2nd vaccinations and have been told that they only use the L4. I noticed a swelling around the area she was vaccinated is this normal. And can I insist that our vet gives her the follow up L2 please.
A slight swelling after Lepto vaccination (L2 or L4) is very very common (in fact, I’d say its basically normal – like a sore arm after our vaccines, it just shows that the immune system has recognised the vaccine). I’d say that in my experience it’s more common after the first vaccine than the second, although it does occur after later ones as well.
In terms of what vaccine he gets, you can ask, but as this is a prescription only medicine, the decision on whether to offer the L2 is the vet’s. If they are recommending L4, it’s probably because they feel that in your geographical area, it provides better protection against the strains of Lepto there.
If you really don’t want L4, your vets may be able to order in a special batch of L2 for you, but be aware you might need to pay for a full box of 5, 10 or even 25 doses, if its a special order just for you.
I would also VERY strongly advise against not getting a second dose, as (like the Covid vaccine!) the second dose gives a lot of the protection.
It is interesting that you removed my post relating to any detailing my dog dying from nobivac. Brushing symptoms and deaths under the carpet is not the answer.
We have not removed any of your posts; all posts are moderated for illegal or defamatory content before publishing that’s all!
Yes, nobivac l4 is dangerous. April 2021 he went to have a new course of jabs, about 3 years since previous. 4 weeks later another nobivac l4. 2 weeks later, the rot started. He developed a temp. Penicillin and pardale prescribed. A week later he went lame. Not physical, but by fluids. He had developed anemia, internal haemoraging. I will stand up and say that is the cause, though my vet defends it “I haven’t heard of any cases” and an emergency vet “it could have triggered an underlying cancer”. Who pays them to say this? Nobivac killed my hewlthy dog, and left me with over 2500+ vets bill. I will get no recompense for this.
I’m so sorry for your loss.
I assume you got a post-mortem to demonstrate the cause? In every case I’m aware of the manufacturer has paid for this. I’d be very interested to see what the results were, because there are very few case where the vaccination per se (as opposed to a coincidental condition or an underlying condition being triggered or accelerated by the vaccine) has caused complex changes 2 weeks after administration. From a biological perspective, it would be very unusual and quite difficult to explain, as the immune and inflammatory processes (which can in very, very rare cases trigger abnormal bleeding) would have been complete by then, and so something to explain why this happened if it was vaccine associated would be invaluable.
Hi David,
Thank you for this excellent piece – as a first time dog owner my pup received an L4 vaccine on her follow-up. I’m surprised that manufacturers aren’t required to publish information on the compatibility of their different vaccines. Is there any regulatory framework that they have to conform to, in this regard? What in your view would be the disadvantages of such a framework or governing body that required them to share research information with each other and the public?
I also wanted to ask another question – the primary disease vectors for leptospirosis are rodents. Specifically is this down to their physiology, or social aggregation? If the latter, should squirrels and voles etc. who are comparatively solitary be considered as potentially as much a threat as rats and mice?
I live in an area where bat faeces are an issue, and I was just wondering if there were any studies that had been done on whether leptospirosis was endemic to the uk populations of bats as it is in other countries (or whether indeed any other animals were known or expected to be potential vectors)?
Thanks very much for your help!
I agree regarding compatibility – the manufacturers have to provide evidence for efficacy and safety, but not (as yet) intercompatibility, so what we know about that is limited to independent research and anecdote. Because of the way that veterinary medicines are funded and licensed, there is no real pressure for intercompatibility studies (which would push up the price as additional studies would need to be performed and paid for out of drug sale revenues). Personally I’m hoping that this is something that will come out of the Covid-19 vaccine research!
The role of sylvatic transmission from dog to rodent to dog is poorly understood. We know it can happen, but how common the rodent-dog aspect is – not so much. It is possible that the primary route of transmission is infected canid to dog, although personally, I think the strong spatial and temporal association with waterways argues for a significant rodent role. The main reason appears to be their ability to withstand a significant bacterial burden of pathogenic serovars while remaining asymptomatic or subclinically infected. That said, even after recovery from clinical disease, even dogs (who generally tolerate leptospires poorly) will shed viable leptospires for many months.
There have been studies of human-pathogenic leptospires in bats (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4643053/) but I’m not aware of any that have looked for the canine-specific serovars canicola, icterohaemorragiae or bratislava/australis. That said, given the unusual nature of the bat immune system, I would agree they are probably involved! The big issue here is of course that Leptospirosis in humans is rare enough that there is little research, and as we have fairly effective vaccines for dogs, again, there’s little research going on.
My Labrador had Lepto 6 at 8 weeks and again at 12 weeks, he is due his booster but the Vet in the UK is only giving Lepto 2. Should I accept this or find another with Lepto 6???
It depends what the risk factors are in your location – I don’t know what strains of Lepto are present on the Channel Islands, so probably best to check with your vet on that one
I’m confused our cavapoo had L2 at 8 weeks by breeder. Our vet says to start L4 at 10 weeks and go out one week later is this right? All the vets say different things!
The reason is that you’re not actually supposed to mix the L2 and L4 – we know it’s safe, but different manufacturer’s have different datasets on how effective it is after each bit!
Generally speaking, the L4 will boost the two components of L4, but the other 2 strains need a second L4 jab to boost them before they become effective.
Hope that helps!
My puppy was given L2 at seven weeks by the breeder’s vet. When I registered at my vet he was given L4 at nine weeks and is due another L4 at thirteen weeks. The vet said that he could go out for walks from ten days after the first L4 (which is today) but not in places where they may have been lots of dogs, rats, farms or stagnant water. Is this correct? Am I right in thinking that he now has full protection against all the strains covered by L2 but not the additional strains in the L4 until the second L4 dose is given?
Yes, that’s right: the L2 will be boosted by the L4 for the first 2 strains/serovars, but the other two only after the second jab.
My dog just died shortly after taking this vaccine. I have now found many groups online who have owners leasing their pets due to the L4 vaccine. Avoid please, it isn’t worth it.
Mine too, and my post detailing what symptoms to look out for was removed.
We have not removed any of your posts; all posts are moderated for illegal or defamatory content before publishing that’s all!
I’ve also seen a number of dogs who died because they weren’t vaccinated. I’m so sorry to hear that you lost your dog – however, death due to vaccine reactions is so, so rare that I would strongly advise you to get a post mortem examination or autopsy done (the vaccine company will usually pay for this) to try and determine what happened.
I’ve recently picked my puppy up at 9 weeks and has had l2 at 8 weeks old and we have upgraded her to l4 at 10 weeks old, when is it she is allowed to go on small walks on the pavement away from water etc
That’s a risk-benefit analysis to do with your vet… however, it’s likely that she’s protected form 2/3 of the common Lepto strains; the third one won’t be covered until after the second L4, but if you’re careful, the risk is relatively low.
Mine too!
Hi there, very useful article thank you and please any recommendations for the following query – my 7 year old Skye Terrier had an adverse reaction to the L4 booster in 2019, so for 2020 vaccination the vet recommended we just have the L2 version. But he’s now due this year’s vaccination and the vet can’t get hold of L2 anywhere, they don’t stock it. The vet has recommended going with the L4 with a course of Piriton 5 days before and after, which I’m not keen on (I don’t want to drug the dog up just for a booster). The vet is calling other local vets in the area, but what do I do if we can’t get the L2 version, any advice?
It depends what type of reaction it was – if it was allergic, then antihistamines might help damp it down, and it would probably be fine. But these reactions are pretty idiosyncratic, meaning that it’s very hard to predict exactly how a dog will respond. Good luck finding an L2 source!
Thanks we found a new vet that offered the L2 vaccination so all sorted.
Due to collect 8 week puppy who has been given Canigen L2 when 7 weeks by Breeders vet. My Vet has advised the following vaccination plan:
10 weeks old – Nobivac L2
14 weeks old – Nobivac L4
16-18 weeks old – Nobivac L4.
Does this sound like a sensible approach and does this mean i will have to keep puppy isolated away from other dogs until the 2nd L4 vaccine at 16-18 weeks old?
Never L vaxx 3 times
This isn’t in accordance with the manufacturing authorisation, but there’s no data to suggest it would be harmful.
That’s not something I’m afraid we can comment on – I would definitely agree with upgrading to the L4 in accordance with the vaccine’s license, but I’m not permitted to comment on the vet’s individual and specific prescribing choices.
You quote the incidence of reactions to L2 as 0.015% and L4 0.069%, that is a ration of 4.6, so reactions to L4 are approximately four and a half times more likely than L2, not three and a half times as as stated in your article.It occurs to me that as the second dose of L4 is given four weeks after the first and separately, then any reactions should only be attributed to the L4.This is particularly so, if one expects an allergic reaction to occur following the second not the first exposure to the vaccine.(I now vaccinate my own Border Terriers with L4 and so far have had no adverse reactions, nor to any previous L2 and other vaccinations over forty five years)
Thank you – I think that was a typo, well caught!
Regarding the timing – it depends on the protocol, there are several different procedures used by different practices. In some places, for example, parainfluenza is given with the second Lepto; in others, it’s given on its onw; and in yet others, it’s the first vaccine that is given alone and the DHP is given in the middle and with the second. But yes, it should be possible to determine that: however, the signal to noise ratio where adverse reactions are so rare makes determining the cause much harder.
A great article, thanks. Can you clarify how long L4 immunity lasts in adult dogs please? My dog has just had his annual booster but my vet has asked me to take him back for another in 4 weeks’ time as it was 10 days beyond the recommended maximum 1 year and 4 weeks between jabs. Does the level of immunity fall off the cliff in such a short time?
12 months, after which it declines fairly fast. There’s some evidence that a repeat dose up to 15 months doesn’t need a complete restart, but it’s not a licensed use of the vaccine, and in high-risk areas, some vets are unwilling to take the risk.
Hi
We are picking up a Jackapoo puppy on Sunday. She will be just under 12 weeks old and is due 2nd round of vaccination. She has been vaccinated with L2. We have found one vet recommending to stay with L2 but all others say we should restart on L4 which will mean we won’t be able to take her out for over a month. Where we live is semi rural – near farms – will we be OK to stick to L2 regime? What if we want to change in a years time? Anyone experience of this?
Ultimately, the risk depends on the exact strains of Leptospires that are present in your area. Unfortunately, there’s no database or system that routinely records this information; we know that in some areas (Glasgow, for example) there are very high levels of the strains covered by L4 but not L2; however, we don’t know what the prevalence is nationwide. For most manufacturers, L4 will effectively boost L2, giving partial protection, and then full protection once the second L4 is given, but that depends on the exact manufacturer of the vaccine your vet is using.
Thanks for a very informative blog post.
Our 8 week old GR got initial shot of L2 from breeders vet. Our vet suggests restarting her with L4. He say booster in 4 weeks and only socialize with other dogs after. Puppy from same litter with same initial L2 was at different vet and got restarted with L4, but this vet says booster in 2 weeks. I’m confused. If she got restarted next week (9 wks) + 4 wks + few days, she’ll be almost 14 weeks. And if they are restarted, shouldn’t the L2 vaxx not giving her any basic protection?
And if lepto is vaccinated annually. Could we not stick with L2 now and maybe restart L4 the following year? I’d rather socialize her (and she won’t be swimming in or drinking from rat infested stagnant water anytime soon. Thanks.
It depends on the exact brand of vaccine and the license! The L4 will normally boost the L2, so we would expect protection against the Icterohaemorrhagiae and Canicola serovars, but none against the Bratislave and Grippotyphosa.If you want protection against them, you will need to restart at some point.
Thanks a lot. We got MSD Nobivac Lepto2 and now restarted Nobivac L4. (Booster in 4 weeks) would you expect immunity for the two L2 strains? Would you expect enough L2 protection for starting some external socialization with known neighborhood dogs (not puppy parks etc). Or better wait for L4 booster We have DHPPi boosters.
There’s no specific data on this. Generally, 1-2 weeks after the second injection, though.
How does L4 react to the vaccination against Canine Distemper, Canine Hepatitis & Canine Parvoviral infection? Our puppy is moving overseas and it needs to be vaccinated at 6 weeks, and at 10 weeks again, but I am unsure how L4 will disrupt this timing and any adverse reactions from so many vaccinations.
The L4 and L2 are commonly combined with these vaccines – as long as they’re from the same manufacturer with compatible excipients it’s no problem.
So I see the hard decisions we need to make to protect our dogs. My belief is that a puppy should have the L2 vaccine and be converted to the L4 vaccine at a year plus.
If you live in the UK. The L2 covers most things UK and L4 also Europe from what I have read. Adverse event reporting is a hit and miss affair and I work in this area. So yes children vaccines have issues and dog vaccines have issues. Suggest like me you do your research and make you decision don’t leave it to the vet as
both L2 and L4 are available a vet who says different should be told you will go to a vet who listens to the owner. Free choice protect your babies make a considered decision.
Could I ask how imperative it is to wait the full 4 weeks between L4 jabs?
My Border Collie pup had the 1st jab at 8 weeks and I can only get the 2nd 3 days early or 5 days late for various reasons.
He’s has diarrhoea since the 1st almost 3 weeks ago which we can only just keep under control with Rioyal Canin Adult wet gastro food. The puppy dry Gastro version results in liquid movements, as does ANYTHING else (45ml of probiotic used up too).
The Vaccination brand is Novivac and he had the parvo & distemper etc the same day.
The 4 week gap is actually quite important with this vaccine to make sure that the immune system is primed properly. I’d suggest talking to your vet about the vaccine interval, as if he’s poorly, vaccination isn’t likely to be as effective anyway.
Thanks
Hello,
Thank you for your article. It is really helpful to read.
We have a 12 week old puppy and the breeders vet gave her Lepto 2 as part of her first vaccinations and when I called my vet to arrange second vaccinations and told them what vaccinations she had been given, I was told she could go out 7 days later.
I took her to the vets and (understandably) due to covid I had to wait outside and when she was brought back outside I was told she had been given L4 and to bring her back in 4 weeks for second vaccinations.
We had arranged for someone to have her with other dogs in their home in 2 weeks time during the day while we are work a few days a week. I had not realised there were different vaccinations and thought all standard across UK vets.
I worry about her having to have so many vaccinations in such little time when so young/ small. And also I don’t understand still. Is each vaccination of L4 the same or is it different?. Is what is in L2 exactly the same as L4 except L4 includes 2 additional or is different. In theory having had one L2 and one L4 is she now fully protected for 2 strains OR does the L4 cancel out what she had for the L2 originally?
What confuses me more is if I had taken her back to the first vet that the breeder used she would be able to go out from this Friday but now I’m being told she can’t go out for 5 weeks (4 weeks to next vaccination and 1 week after).
I just wanted to clarify what was correct.
Many thanks for your time
Don’t worry! It’s not as straightforward as it looks.
Basically, L2 has 2 strains of Lepto in (Canicola and Icterohaemorrhagiae). L4 also has those, but also Australis and Grippotyphosa (making 4 in total). So, if you’re using the same brand of vaccine, L4 will happily boost the first two components in L2, you just won’t get protection from the other two (although there are some Australis strains present and fairly common in the UK – hence why many vets have moved to L4).
However – if it’s a different brand of vaccine, it may not contain the exact same serovars (or families) of each strain. The big problem with Lepto bacteria is that the cross-protection between different serovars, even of the same strain, is very variable. All the manufacturers include slightly different serovars, chosen to give cross protection against the “wild-type” bacteria. But if the serovar in the primary vaccination isn’t cross protective with the serovar in the second dose, then there may not be effective protection generated. And this is where the issue comes in – because the manufacturers (understandably) don’t keep a record of what other brands their vaccines work with, and because of quirks in the licensing laws, we are forced to assume that there is no cross protection unless proven that there is.
Bottom line – different brands when used for first and second vaccine MAY give protection, but equally, they may not. The good news is that if they DO give protection, then an extra vaccine 4 weeks later seems to be very, very safe.
Hi David, I recently brought my Golden Doodle puppy home from the breeder. She was very much against any lepto vaccine especially the Lepto 4 and suggested that vaccinations are more effective from 12 weeks rather than 8 weeks. I have chosen to vaccinate my puppy at 10 weeks, as a compromise as I think it is important for puppy to get out and socialise, although I will be doing this by carrying her so she discovers new sights and sounds. I am so torn in regards to the lepto 4 vaccine and getting quite distressed, my vet recommends it and has never seen an adverse reaction buy it conflicts with my breeders advice. I have read that reactions are more common in golden retrievers which is why I am so undecided.
I’ve never seen a serious reaction to L4 in practice; while I’m not saying they can’t happen, I think they’re really rare. The figures are very reassuring! I’m not aware of any data suggesting that Golden retrievers are actually at higher risk, although it is possible – however, I do know that a lot of breeders (of all sorts of breeds) say that their dogs are at increased risk. I think there’s a lot of Chinese whispers going on here, sadly, and it’s not backed up by the facts that we have.
The last thing I’d point out is that your breeder is an expert in getting dog’s pregnant and raising them to a couple of months old. Your vet is an expert in keeping them healthy and treating them when they’re ill.
I hope that helps!
My 3-year-old German Shepherd had a seizure after changing from the L2 to L4 and some mucus diarrhea. Luckily just one seizure (fingers crossed still early days) and the diarrhea has now cleared up. His vets have noted the reaction on his records and sent a report. I do think reactions are greater than is being reported for the L4. Everyone knows someone whose dog has had a reaction to the L4. Sadly due to this all vaccinations are now coming under suspicion. My research since my dogs reaction is now making me question the L2 – which he has had without issue. Many people I know are testing and not vaccinating at all. So far there has been no rise in cases of illness as a result. What the L4 has done in conjunction with vets refusing to acknowledge a problem – is undermine vaccination and the profession. These are just my thoughts after talking to people. Will I now vaccinate Milo? will I vaccinate future dogs? Right now I do not know what to do for the best.
I personally would not have the L4 , I’m all for vaccinating but I do not believe in over vaccinating , over flea treating or worming and with 10 Dogs ranging from the age of 4 , 6, 7, 10, 12, 13, 2 @ 14, 15 and to 17 years ( none ever ) suffered illness , all neutered aswel, none have been on any medication in their lives I’m content what I’m doing is working, I always primary vaccinate then again around the 5 year mark then stop , I don’t flea unless I visually see one and I dont over worm and try to feed food not packed with preservatives .
Unfortunately, there’s no test for immunity to leptospirosis.
If it helps, I’ve never seen a reaction to L4 except for the occasional and temporary swelling at the injection site; the vast majority of vets I’ve spoken to say the same thing. So either all these people who have had reaction haven’t done the sensible thing, that you have, and told their vets, or there’s something else going on – and I’m afraid that mass hysteria about vaccines is nothing new.
What a great article and also excellent evidence informed comments. As a healthcare professional, we are guided by the data and evidence. That’s all we have. No data without stories and no stories without data. I could have the flu jab tomorrow and unfortunately have a very rare reaction to it. Unlikely, but I could. Same goes for lepto. Would you go to the doctor and argue about their decision making?
We use the L4 on our Cockapoo girl and will continue to ensure the L4 is given to all dogs we own. Our girl loves swimming and is always in water as we live in a rural area. Vaccines keep diseases at bay which are significantly worse than a quick scratch at the vets. It’s our duty as responsible owners to protect our animals and give them the best start and ongoing care. There are always unfortunate cases where things go wrong but this is vastly outweighed by the amount of successful vaccinations done every day.
Great informative article!
Both my 8wk French Bulldog girls were done last Tuesday & are fine. 1 is with her new owner since yesterday & will be coming back to me for her 2nd vaccine. I have owned horses for 40yrs & none ever had a reaction to the flu jab, but I have known others react. Didn’t stop me having mine done.
I would like to ask a question regarding immunity for puppies from the mother and how long this lasts please? Thanks
Unfortunately, there is no useful test for Leptospira immunity – antibodies are short-lived and levels do not correlate with protection. It is likely that puppies pick up some immunity to Lepto from their mother – but this is not certain, and there is very little research. This makes sense when you consider that the only reliable way to demonstrate maternal protection would be to deliberately infect healthy puppies with lepto and see at what age they started to die. Clearly this wouldn’t be an ethical experiment and to the best of my knowledge, has never been performed.
In any case, the minimum age for vaccination with both the L2 and L4 vaccines is 6 weeks, to ensure that they are immune competent and able to respond appropriately to the vaccine.
Of course because all veterinary members of staff are made of money and call your dog in for its annual booster just so they can go buy a new car. Medications all have risks, they could have underlying conditions which causes these deaths rather than the vaccine. Of course if you was the owner and got the dogs post mortems then perhaps you would have valid information that it was the vaccine that caused the issue. I hope no immuno compromised dogs get ill from the unvaccinated dogs on your advise as that would be very sad.
My dog’s first injections were L4 – her one year booster was an L2 (the vet did not check her paperwork before injecting her). He then said we will have to restart the vaccination as if she was a puppy and another injection would be needed 2 weeks later. Or we could get another L4 booster 2 weeks later.
He then phoned me and said no further injection is needed as the L2 will boost the 2 of the 4 in L4. Does anyone know if this is the case? After doing some research it would be good to avoid having an additional L4 if we could but obviously want to make sure my dog is protected.
Essentially, the L2 contains 2 of the 3 common serovars (versions) of Leptospira found in the UK (Icterohaemorrhagiae and Canicola); the L4 contains the third (Bratislava). The fourth strain (Grippotyphosa) has not been widely recognised as present in the UK at this time.
Theoretically, the L4 should boost the Icterohaemorrhagiae and Canicola. However, you are not protecting against Bratislava, which is present in the UK. As far as we know, there’s very little cross-protection between serovars (so being protected against one is unlikely to protect against another), and unlike some of the other vaccines, the duration of immunity is very short.
Ultimately, it is up to you and your vet to decide what risk your dog is at – with the L2 vaccine boosted, your dog should have about 2/3 protection against UK strains, the question is whether you want to cover for the third.
The only additional comment I’d make is that if you intend to take your dog to the mainland EU, then I would strongly advise the L4, as the Gryppotyphosa strain is very common in Germany in particular.
Hi – I found your article really informative. My puppy had the Lepto 4 vax on Monday 21 October – that’s his very final injection. When will it be safe to take him out for a walk … my vet said 3 weeks, he will then be 16 weeks old, is that correct or will he be safe to walk earlier than this?
3 weeks is usually about right – how long it takes immunity to become firmly established after the second vaccine is variable, but listed by the manufacturer as 3 weeks – hence the waiting period!
I’ve got 4 dogs all are foreign rescues! 2 are coming up for their annual vaccinations (they are 2 1/2). One dog is a lab x lurcher and she had a severe site reaction from the vaccination last time so I didnt take either of them back for the follow up lepto that was due 4 weeks after the initial vaccinations.
My question is – I would like my dogs titre tested to see exactly what vaccinations they now require. Is it ok to ask my vet to titre test first? Or should I just go ahead and get the vaccinations but stick to Lepto 2…
I think if one of them has had an unusually bad site reaction then a titre test might be a good idea. However, remember you can’t do a titre test for Lepto (the results are meaningless because the vaccine doesn’t work by generating antibodies but a cell mediated response). It’s impossible to know which component to the combined vaccine your dog reacted to, but a titre test will let you know which (if any) of the initial distemper, parvo and hepatitis components have taken. Regarding the Lepto component, if they only had the initial dose not a second one, they have no induced immunity to leptospirosis at all – because it’s a dead vaccine, 2 doses are needed, so they will need to restart the lepto vaccine schedule from scratch
the lepto vaccine does not give a dog immunity, he can still get the illness
I’m afraid you are incorrect. The immune system responds to the vaccine and dogs develop some degree of immunity – as I said in the article, vaccination against leptospires is good at reducing the severity of infection and very good art reducing carriage. This is one aspect of immunity. While I wish it did prevent all infections, sadly, no-one’s managed to produce a vaccine that does that yet, so we’ll have to settle for one that means that dogs if infected are less likely to die and less likely to pass the bacteria on.
My 3yo pup had the first dose of his first ever L4 vaccine (previously had L2) and was due the booster 4 weeks later, however I missed the appointment and have only realised now – week and a half later.
The front desk lady at the vet’s said he’ll have to start over, and the Nobivac information sheet does specify a 4 week interval.
I’m very worried about essentially giving him 50% more in a very short space of time by restarting the vaccine. Was wondering if restarting but with L2 could be safer. On the other hand, ha hasn’t had a reaction after the initial dose of L4. Would really appreciate your thoughts before I speak to my vet.
To be honest, it’s very hard to know what’s the best thing to do in this situation. I think the probability is that even with 3 vaccines relatively close together, there won’t be a problem – but as with any medicine, it’s impossible to guarantee that. I’d be include to chat with one of the vets about it, rather than the receptionist; personally, I would probably restart the vaccine with both L4 components, but this is entirely your call. The thing with the L4 is that its a dead vaccine, which means that the immune system doesn’t respond as powerfully to it as to the live vaccine components – this is why 2 doses a set period apart are so important.
Sorry but this article is very strongly worded in the ‘Pro’ vaccinate, in my opinion. Words like “‘supposed’ to have died” are not helpful. Also, the major study in Scotland was, I believe on strays so you could, (using similar logic to that in your article) posit that strays never had a vaccination for lepto and if they have the disease seem to have survived – making lepto not always deadly and EXTREMELY rare.
Also suggesting that as 5% of strays were infected and excreting the virus poses a 5% risk to all dogs is great example of lies, damn lies & statistics. Is your dog hanging round with THIS sample of strays in Scotland?
The truth is that leptospirosis is a VERY, VERY rare disease in the UK, (and in Europe). Humans can contract it too BTW, (every heard of anyone taken ill with a dose?). Humans are not advised, (in all but the most extreme environments) to vaccinate against it – it’s too rare Vs the risk of reaction to the vaccine.
Does your dog spend a lot of time around farms and farm animals? Do they like stale or stagnant fresh, (not salt) water? These are the at risk situations.
Learn the symptoms of lepto, (similar to flu) and get your pup off the vet for some antibiotics (which do a great job of killing lepto) if you suspect a case.
BTW L2 or L4? L2 cover 2 ‘strains’ and L4 covers 4 ‘strains’ of lepto. There are about 200, (possibly more) known ‘strains’ of lepto and at best your protected for (the most common? difficult to tell as ITS SO RARE) 2 or 4 with all the side effects, (deaths) this entails OR don’t take your pal near stagnant water or farm animals and know the symptoms of this VERY rare disease.
Titre testing for DHP is a much better idea that dosing every three years. You’ve vet shouldn’t complain about this as the titre test, (blood test to check for the presence of protection) costs about the same as the DHP booster itself.
In short, don’t panic lepto in dogs, (and humans) is VERY RARE. Would you vaccinate your child for lepto if they crawl around the grass near ponds? I can happen tho, so know the symptoms and act.
The main reason lepto infection is rare is because most dogs are vaccinated, so that’s something of a circular argument! And yes, in general I am pro-vaccination because in general the evidence supports it as a way of improving animal health and welfare. Meningitis in humans is also pretty rare, but the meningococcal vaccine is still generally accepted as a good thing…
I have seen dogs (and humans, as it happens) with clinical leptospirosis and antibiotic treatment is far less effective than you suggest – 20% mortality figures are usually quoted despite treatment – hardly doing “a great job of killing lepto”.
Leptospirosis is present in the UK (three of the four serovars in the L4 vaccine) and it does kill dogs. Not all dogs, of course, but far more than any actual evidence suggests have been killed by the vaccines.
One one thing we do agree though – titre testing is a great innovation, and I absolutely support its use. For distemper/hepatitis/parvo, it’s a great way to tell whether your dog is one of the lucky ones with multi-year immunity, or not.
Is the Lepto 2/4 vaccine Live or dead bacteria, if we are having multiple dogs vaccinated over a span of say one to two months does this leave the adult dogs and pups not yet vaccinated exposed to contracting the disease due to the others shedding it, we had a couple of dogs react negatively to the L4 three yrs ago, after having L2 with no real side effects and so have stayed away from this vaccine since but feel it in the dogs interest to get them covered, we just want to do it safely and wisely. Our Vets are brilliant and will support us by providing L2 if this is what we choose but have also been good in giving us reassurance if we wanted to explore L4 again with some of the dogs, with so much worrying information out there there is a temptation to just not have either but i know if the disease is contracted its life threatening, we also advise new puppy owners on this, mainly saying to them to ask their vets advice but would be nice to have some answers to the above Thank you for your time
No problem, thanks for commenting! Both the L2 and L4 vaccines are dead and do not contain any live bacteria; as a result, shedding isn’t going to be a problem with these products.
Thank you for your reply much appreciated and helpful
We have a labrador retriever, our 2nd one from the same breeder who has been established for over 50 years. They stressed to us that we should stick to Lepto 2 and not Lepto 4. Today, our dog has had a Lepto2 booster, he is 15 months old and very healthy. Do not be strongly persuadedy to upgrade to Lepto 4, do some research and make your own judgment. We have, and we certainly would not take the risk which is what it all boils down to.
The L4 protects against diseases that are present in the UK and kill dogs in the UK, which are not included in the L2. That said, these strains (or serovars) do appear to be less common than the other two. It is a very safe drug compared to, for example, paracetamol in humans, but there is some evidence suggesting there are slightly more adverse reactions (although these are mainly minor) than the older vaccine. So yes, definitely do your research, but remember to include unbiased, evidence-based and peer-reviewed sources, not just rumour and anecdote.
Yes please do include dear David Harris some unbiased, evidence based research on how many dogs have dies of lepto in the UK in the past few years. Please do. We want to see your evidence
If you follow the links in the text, you’ll find the original research that the article is based on.
We are bringing home our 8 week old cavapoo on the 5th September. The breeder’s vet gave her the first L2 injection on 29th August. We live an hour away from the breeder and will be using our local vet Vets4Pets for future injections, unfortunately they use the L4 injection.
We have decided to go back to the breeder’s vet for the 2nd injection, thereafter using our local vet. Who, I might say, have an excellent reputation.
I have concerns about the L4. Breeder says stay away from it, yet vet says I should do. I trust my vet, but something not sitting right with L4. I think I will compromise & give L2 whilst a puppy & when comes to annual vacs change to L4 – he’ll be bigger & stronger by then & also gives me an extra year to research. Is it ok to start the vacs off again at the annual booster – i.e change to L4? I don’t think I’ll have any choice but to do that – as insurance says has to have the annual boosters
The problem with the L4 vaccine is one of perception, rather than safety, as far as we can tell from actual evidence (rather than rumour). Any vaccine can have side effects, of course; mild side effects do seem to be more likely the first few times a vaccine is given than subsequent ones, but this again might be anecdote, I’m not aware of any actual evidence on this!
I would certainly say to use L2 rather than no Lepto vaccination; however, bear in mind that boosting L2 with L4 does not give your dog immunity to the 2 additional strains of Lepto in the L4, so would not be in accordance with the manufacturer’s license or presumably the insurance company’s terms (although you’d have to check that with them). The only way to do so would be to restart the lepto vaccination course with 2 injections, 4 weeks apart, when you decide to change over to L4.
Hope that helps!
Hi my 5 month old cockapoo had his 2 injection of leptospirosis 4 last night within a minute at the vets he started crying in pain. We took him home he looks very depressed and keeps crying every now and then especially when he moves or gets up. He is led down alot which is totally out of character for him and he has not eaten any breakfast . My concerns are will he get over this or will it get worse and also if he does get over this what do I do in a year’s time after a reaction like this do I just get leptospirosis 2 done as he had an awful reaction to leptospirosis 4?
Any help with this decision would help.
Thanks
The Lepto vaccine does sting, but lasting side effects are very rare. Many animals are a little off colour for 24-48 hours after a vaccine – this is because the vaccine is stimulating an immune response (it has to to work), which often makes them a bit lethargic. I would be very surprised if he didn’t bounce back after a day or so (although there might be a small swelling at the injection site that takes a few days to go down). I would not say that this was a reason not to vaccinate next year, assuming the effects resolve as quickly as they usually do, because Lepto infection is much more unpleasant and very unlikely to resolve rapidly and harmlessly on its own.
If the effects are at all prolonged, though, do make an appointment to get him checked out by your vet – a very small number of dogs do develop more serious side effects, although they’re very rarely dangerous.
I got a Jack Russell terrier. I didn’t know anything about L4 so she got the first dose two weeks ago. Reading my papers, I realised I need to repeat same dose again four weeks later. My questions are:
– is it necessary to repeat dose?
– what about if I do a titer test first to see if second dose is necessary?
– If I have to give her second dose, it would be better to wait more than four weeks so her body will have more time to recover from the first dose?
Your opinion and advice would be very useful.
Many thanks.
Hi Paloma, thanks for getting in touch. With initial vaccinations, two doses are usually required in order to be effective to start the course. Following on from that, your dog would need ‘booster’ vaccinations at varying intervals throughout their life to maintain immunity. I’d recommend contacting your vet regarding the second dose of L4, when it can be given etc. as it can vary depending on the manufacturer of the vaccine, so your vet will be best placed to advise.
I order the L2 vaccine from viovet – it’s not that expensive at all. You need a prescription from your vet to order.
I’ve had this discussion for the last 2 years with my vet, and every year I’m persuaded by the vet (honestly it feels more like being forced) to have L4. This doesn’t sit well with me at all, I know of and have met several chihuahua owners who have lost dogs after vaccinations with L4, can I ask my vet to only use L2 or will I have to find another vet who will do it? I asked once if I could order L2 in for my Chi and was told I’d have to buy a whole tray for around £150.
I’m happy to pay for a prescription and order it myself, even though I pay for vaccinations and parasite prevention through a care package. I feel like I should have the final decision, as the owner, about my dog’s vaccinations. Or am I wrong? How is the best way to ask this of my vet? I haven’t succeeded so far.
Why don’t you just yo to a different vet for your vaccinations ? Please don’t get the care package, all it does it tie you to that vet to force you to use their products by making you feel you cannot go elsewhere( it’s a huge marketing ploy) , for vaxes and wormers and flea treatments you should always shop around and you certainly dint need to over worm and over flea ( again it’s a huge money maker) , make sure you have insurance but honestly cancel the care package
I know a vet who refuses to give the lepto shot to any small dog because he has had so many die. Even when the owners ask. If your tiny dog is not drinking from puddles or streams, he does not need this deadly shot.
Then your vet is very unusual – I have never seen a dog die from Lepto vaccination, and nor have any of the colleagues I’ve talked to about this. Tragically, side effects happen. However, here in the UK where we’re based, the guidance is to treat Leptospirosis as a core vaccine, because the bacteria are so common. Perhaps Leptospires are less common in the US?
My dog developed ITP and died 8 weeks after the lepto shot. His bloodwork and health were PERFECT and then the shot. Both my vet and the critical care vets admit it was the shot and reported it to the USDA. A Great Dane, one town over had the lepto shot and died the next day. That shot is killing dogs whether you want to admit it or not.
I never said that isolated and very rare tragedies don’t happen. I just said that they are very rare, so much so that I have never seen one, and nor have any of my colleagues.
A vet I know has knowledge of reports of lepto vaccine deaths to the USDA that mysteriously do not appear in their yearly report. Having worked for a major pharmaceutical myself, I am not surprised.
I can’t comment on the US system (although given how poor the reporting on US datasheets is, I’ve not been desperately impressed in the past). However, I have never seen any serious side effects from leptospirosis vaccines, nor have any of the colleagues I’ve worked personally with.
I’m not saying that there aren’t side effects (anyone says a treatment has no side effects or risks, they’re either lying, misinformed, or it doesn’t actually do anything) – however, all the actual data (not counting rumour and anecdote) suggests that serious ones are very rare.
An open discussion about the risks and benefits is the best way forward. However, the vaccine is a prescription only medicine, and strictly you have no legal right to demand a product that your vet believes to be less effective. It sounds as if they have offered to source it, but that the cost was something you were unwilling to bear (which is fair enough).
It is possible to order the L2 from some veterinary dispensing pharmacies – although you will have to pay for refrigerated delivery. If your vet was willing to order a tray of L2 in for you in house, then they cannot legally refuse to issue you a prescription for the same drug. Just make sure you choose a reliable and reputable UK-based pharmacy or dispensary that is properly inspected and regulated!
Before we picked our new puppy up he was given his first L4 vaccine at 10 weeks. I contacted our local vet who only uses the L2 and they said it’s fine for him to have the second vaccination of L2 as it is compatible with the first L4 vaccine; is this correct? He is due to have to second jab in just over a week (12 weeks old) and I just want to make sure he will be fully covered.
Yes, the L2 can boost the L4 (because L4 contains the 2 components in L2); but you won’t get the protection from the other 2 elements.
Our puppies breeder had them vaccinated with DHP and L2 after 7 and a half weeks. After we picked her up at 8 weeks we took her o the vets after a couple of days for an initial check up and the vet recommended giving her the L4 even though it was only 1 week after having the L2. We have been told to go back in 4 weeks for the top up of L4 but in the mean time we can take the our puppy out a week after the first L4 vaccination.
I’m nervous of taking her out before she is fully vaccinated and am wondering if we can go back to the L2 vaccination after reading the risks of L4.
Is it too late to go back to the L2 once she has had the L4?
Thanks
The difference in risk between the two really isn’t that dramatic, and the additional cover provided could be invaluable. Remember, we never hear about all the millions of dogs given L4 who DON’T get side effects and DON’T get Lepto because they’re protected, only the very tiny number who do.
However, if you think that the risk is too high, it’s absolutely your decision, and it is the responsible thing to do to make sure your dog is protect against the other two strains. The good news is that yes, you can convert back to the L2 from the L4, because the L4 contains both the strains in the L2.
My Labrador pup was given dhp and L2 at 71/2 weeks the note on the vaccine card said between 2-4 weeks for the next I made the appointment for 2weeks later and the vet said she should have L4 due to us living by a lake she also said we need another dhp in 2 weeks and the second L4 in 4 weeks is this right will I ever be able to put my puppy down to walk in the park my 6yr old lab had one shot at 8 and one at 10 wait 10 days then she could be walked any advice
It depends on the exact brands, but yes, the time interval between 1st and 2nd L4 is different to that for L2 – and for many brands it does, sadly, mean an extra trip.
Why give lepto 4 when 50% of the strains covered by this ‘new’ vaccine aren’t rampant or even partial to the UK’s climate? why give this vaccine when most cases can be rectified by antibiotics? This vaccine is killing animals, my dog developed 5-6 grand mal seizures daily, even on a high dose of pheno etc, he developed bladder stones and kidney failure, all within a month of this drug. Find me a vet who would call these complications a coincidence, because that’s what the majority of vets are doing.
if you must vaccinate, use L2.
I did discuss those points in the blog, you might find it useful to follow some of the links to the original data.
According to the best data we have, about 1 in 20 dogs in the UK has been exposed to one of the new strains (Bratislava), whether or not the bacteria like it here, they are living here quite happily!
Unfortunately, the infection cannot be simply “rectified” with antibiotics – even with antibiotic treatment, about 60% of infected dogs are reported to die.
While I’m really sorry that your dog became ill, there really is a chance that it was a coincidence. It’s difficult to see how vaccination could lead directly to bladder stones, for example. Statistically speaking, the risk of an adverse reaction to the L4 vaccine is about 7 in 10,000; however, the main reason that infection is still fairly uncommon is because most dogs are vaccinated, giving some level of herd immunity and restricting the transmission of the bacteria. Unfortunately, the more scare stories about vaccines are spread around, the higher the risk to other people’s dogs (and their families) becomes.
There is no research done on canine lepto in UK. The only one I could find, and I have access to a lot of research paper, is one from 1991 done on stray dogs witch actually shows the contrary of what you are saying. There is no evidence anywhere that anyone is keeping track of how many dogs died in the UK of lepto, so I guess the number is not so high is it if none find it worth to bother. If you know of any research papers proving that lepto is prevalent in UK (please do not share research done by the medication company which makes money from the vaccine, but independent research) then please share with us.
There are some more recent papers. For example:
Ball, C., Dawson, S., Williams, N.(2014) “Leptospira cases and vaccination habits within UK vet-visiting dogs” Veterinary Record 174, 278.
Who found that “We demonstrate that canine Leptospira infections are present in the UK despite vaccine availability, and that dogs are dying as a result of such infections”
Taylor, C. (2019) “Canine leptospirosis in the UK and Ireland” Veterinary Ireland Journal 9:5This article covers the presentation, diagnosis and treatment of leptospirosis in dogs, and also discusses the limitations of the current tests and the risk of false negatives.
Sant’Anna, R., Vieiraa, A.S., Oliveirab and Lilenbauma, W. (2019) “Asymptomatic leptospiral infection is associated with canine chronic kidney disease” Comparative Immunology, Microbiology and Infectious Diseases 62
Have a new perspective on the possible side effects of asymptomatic leptospire carriage.
David, can you test for Leptospirosis as you can for the core vaccines?
Unfortunately, the titre tests that can be used (and are very helpful!) for the core vaccines are useless for leptospirosis. The reason is that the protective immunity doesn’t seem to involve antibodies (which may be present in an unprotected dog, or absent in a protected one, or vice versa!) but cell mediated immunity. In a natural infection, antibodies are produced so can be used to detect infection, but they aren’t terribly protective.
You talk about The Dog!!!
I have just read numerous stories about dogs’ who have died after this vaccination not “the dog”.
I have just returned from the vet having my 3 Labradors vaccinated. I had no idea that the vaccine had changed to L4 and L2, I am now in such a quandary as to whether I should take them back in 4,weeks?
I have been with this practice for 21 years, although I understand that they were taken over 3 years ago, totally devastated for these owners who have lost their beloved pets, but please let us have some facts about these new vaccines?
I was answering sg’s question about the side effects that her specific dog developed.
Yes, there are lots of stories about dogs that have died – however, I have never seen such a reaction, and nor have the vast majority of the vets I’ve spoken to. The VMD (the medicines regulator) is unaware of an epidemic of serious side effects related to the L4 vaccine.
If you want reliable facts, take a look at the links in the article, and be cautious of uncurated social media groups.
Check before Annual Boosters – Unfortunately there are some unscrupulous vets who will advise on and administer annual vaccinations when they are not needed. Depending on the manufacturer of the Vaccine boosters should only be administered once every three years. Be sure to check and challenge your vet over this!!
Absolutely correct – most dogs and cats do not require distemper, parvovirus or canine adenovirus any more often than every three years.
However, it’s important to remember that some vaccines – such as Leptospirosis or parainfluenza – do not last significantly longer than a year, and for these components, annual revaccination is required to maintain effectiveness.
Thank you for this news. Both my dogs were vaccinated with L4 recently, totally against my approval. I have heard so much bad news about this vaccine. At least I will only have to watch them both for one year if any bad side effects were to happen. I have moved to a new local vet now.
Get their blood checked after 4 weeks. Check for protein in their urine…that was the indication that ITP was starting with our GSD, from the lepto vaccine.
ITP is horrible. I’ve treated it in vaccinated and unvaccinated dogs and it can be really hard to manage.
My neighbours healthy 7 year old Westie died 3 days after having a annual booster. The little dog collapsed and died in the garden. Another local dog (a two year old Springer Spaniel) had a booster and died the next day! DO NOT HAVE ANNUAL BOOSTERS DONE! Your dogs don’t need it! It’s a money getting game by Vet’s!
I’m really sorry to hear about your dog; please accept my condolences.
However, dogs do need annual boosters if they want protection from Leptospirosis, parainfluenza, and kennel cough, among others. Very, very few vets give parvo, distemper or hepatitis annually – it’s well known that these components last 3+ years, and as recommended by the WSAVA and the manufacturers, I don’t know any vets who do vaccinate against these components every year. There’s evidence to suggest many, possible most, dogs maintain immunity to parvo, in particular, for many years, but some do not; in this situation, revaccination every 3 years or titre tests to see how long the immunity lasts are more appropriate. There are no such tests for the other diseases (kennel cough, parainfluenza, leptospirosis etc), and the evidence suggests that these vaccines do not last more than 12-15 months. There’s some great information about the safety and effectiveness of modern vaccines compiled by the WSAVA’s Vaccine Group here: https://www.wsava.org/guidelines/vaccination-guidelines
I think it’s disgusting that vets do not promote titre testing. I lost 2 dogs at 5 yrs old and I am sure over vaccinating, continual worming and flea treatments caused their deaths. I refuse to put any chemicals in my dogs. My dogs haven’t needed a booster for 4 yrs now. They also haven’t had worms for 5 years, I get their poo checked but my vet always asked if their worming is up to date… NO, BECAUSE THEY HAVENT GOT WORMS.
Faecal counts aren’t terribly good at detecting worms, unfortunately. And virtually all puppies are born with some worms – because of their biology, we have to assume that all dogs have at least some pretty much all of the time.
Modern vaccines and flea treatments are among the safest medications that have ever existed; that said, like any effective intervention, they do have some side effects. I assume you got post mortem examinations on your dogs to determine the causes of death? If there’s any possibility that it’s due to a medicine reaction, the drug company will usually pay for it.
Titre testing is great, I have no problem with it – but sadly it’s useless for leptospirosis because the immunity to leptospires doesn’t generate significant levels of antibodies; it’s a T-cell based response, which cannot (as yet) be reliably measured. We know the vaccine is effective at what it does, because it’s been demonstrated through challenge, but there’s no simple test for immunity.
Our Golden retriever died 5 weeks after having the l4 vaccine and 1 week after the top up. We had moved with our usual vet to his own practice and was told by him when it came to Tilly’s annual booster, that they administered this vaccine!! We had nothing but good faith in him.!!
Tilly, whilst 11 years old was fit and healthy and was told so by the vet the week the vaccination was administered.
A week after the top up, Tilly suddenly collapsed and there followed numerous emergency tests including every cancer imaginable and some tested twice. Her blood count had plummeted and her platelets very very low. The conclusion was hard to diagnose with an auto immune disease the most likely. All symptoms now pointing to the vaccine, which even the Vet mentioned but when questioned, tried to talk about anything and everything but the vaccine! We then did our research as was shocked to see the results of thousands of dogs in the UK alone had died from the vaccine. Let alone around the world. Basically on reading because millions of dogs were saved by vaccines the thousands that had died where basically collateral damage!! Heartbreaking for any owner to read this. Tilly was, as have all our dogs, been our babies and loved and cared for doing everything in our powers to keep her and them safe, for this to happen. read on…
The week Tilly dies, on the Monday we had some good news that her blood count had started to rise with the Vet telling me he could be cautiously optimistic !! So much so i felt i did not have to have so many carers in to help sit her! So WRONG…
On the Thursday, 3 days before Christmas after popping out i had an uneasy feeling Tilly was not right and on returning home to find her collapsed on her bed looking back at me. The look told me everything and i placed her in my arms and she gave a little whimper and i knew this was the end. Calling the vet who got stuck in traffic along with my husband also stuck, Tilly was in agony for two hours struggling to breath. Finally the vet came and was not able to stop her agony by helping her to go to sleep!! Her veins had all flat lined, another example of the auto immune disease. She finally died in awful agony. That experience broke us and all where crying for our beautiful girl.. I will never forget or forgive the vet. For us, no matter what you vets may say about keeping animals safe, exactly how much are you all influenced by others to take this vaccine!!!
My Tilly was not collateral damage, she was a much loved, spoilt gorgeous dog rescued from cruelty at the age of 4 with half her body weight and coat tin an awful state and beaten to be killed mercilessly a few years later for trying to keep her healthy.
So you ask, should you upgrade from L2 to L4? No No No never.
WE are now owners of a cockapoo and are terrified of vaccines but have allowed the puppy ones and still, after talking to our original vets concerned about his annual boosters but are caught between vets and insurance companies who insist on vacination!!
There is a titer test that can be taken to determine to see if the dog is still virus free and are considering this before going ahead with boosters. This experience has scarred us for life and will never get over it, Vets need to be more aware of how vaccinations can have adverse reactions on dogs….
This is not on line scaremongering as you say. This is FACT, an awful awful FACT. Do not undermine genuine dog lovers who keep their dogs healthy only to be let down by vetinary practices!!
I am experiencing all of the emotions that you are after losing our HEALTHY German Shepherd on 7/17/20 to the lepto vaccine. I am not dropping this. I am going to try to get a law passed in Connecticut (USA) where vets have to disclose what the shots are for and the reported adverse event and get your authorization in writing. That should reduce a huge number of vaccinations and therefore deaths.
To be honest, any vet should be telling you what the vaccines are for! That’s a basic principle of informed consent for any medication. The risk of tragedies like yours is very low, but there is no such thing as a 100% safe medication (although most of the ones we use are a lot safer than, for example, crossing a road).
In 40 years, 6 practices and about 20 vets, NONE of them have EVER told me there were risks and that there was a safer alternative – blood tests (titre test). I would have done that. They know I cook for my dogs, don’t put pesticides on or in them and would therefore do whatever I could to ensure a long life. These vets are not hicks in a rural area, they are Connecticut vets who charge a LOT of money to kill your dog. You don’t really know the risks because vets are not reporting all of the adverse events and the ones who do, their reports sometimes are left off of the USDA report.
I’m not US based – USDA have no jurisdiction here. The UK’s VMD are excellent for collating the data, which is independently submitted by vets and pet owners (they’ll take adverse reaction reports from anyone), but I appreciate this may not be the same in all countries.
Regarding titre tests, they’re great for distemper, hepatitis and parvo antibodies, but are essentially useless for Lepto. This is because immunity to leptospirosis doesn’t correlate well to antibody levels – some dogs with a high titre are susceptible to infection in challenge studies, while some dogs with a low titre are still protected. It seems that cell-mediated immunity (T-cells) are more important for protection against leptospirosis than for the other diseases.
In terms of professional ethics, I’ve never practiced in the US so I cannot really comment, but I do know that over here informed consent means that people should be made aware of the existence of possible harms as well as benefits before any treatment is given. I know it doesn’t always happen, but it certainly should, and it’s been normal procedure in all the practices I’ve worked in.
Which did you give yr new pup L2 or L4. As getting a pup soon and dont know which ti give after my dog dying aged 11 6weeks after having booster L4 with auto immune disease I’m convinced it was the booster that killed her. As a pup she had her first injection and developed puppy strangles which is an auto immune disease. But worried if the L2 is enough cover.
It is certainly possible that the vaccine triggered a latent autoimmune disease, but it is statistically unlikely. On the continent there’s an L6 which is regularly used, as there are more pathogenic strains in central and Eastern Europe than over here, but we definitely have 3 of the 4 in L4 present and causing infections in the UK.
I recently had a bad experience with this vaccine I had a beautiful litter of border collies 3 boys 4 girls, all healthy good size and progressing well. I booked them into the vets where my puppies mum is registered for their 1st injections and microchips, I never got a choice of which strain I wanted them to have anyway the vaccines was given to all my puppies their was some little cries from some of them. Anyway the next evening my partner noticed that one of the little boys was making strange noises whilst trying to breath so he picked him up and laid on the sofa with him I noticed that he was burning red hot so tried to cool him down by laying him on our laminate floor he was there for about 20 minutes before he had a massive seizure that’s when we knew there was something seriously wrong so I got him in to the emergency vets, 4 more seizures on the way there, once there they checked him over he became blind and brain damaged due to the seizure and lack of oxygen it felt like they was accusing us of hurting him as they kept referring to it looking like he had sustained a head injury (we had been with him all the time not left their sides) so we knew it wasnt he was healthy before that vaccine, strong healthy hearts and good weight according to our vets. We was advised to have him put to sleep as their was nothing they could do for him with how young he was. Devastated was an understatement I had watched this little puppy grow and he had just started to show his little personality. He never got to feel grass under his feet or have his 1st walk. So I’m totally with you on this matter I will never allow that vaccine again they are not collateral damage they are living breathing creatures and loved family members and I will advise anyone that I know that’s gets a new fur baby to no go for that vaccine.
I’m so sorry to hear about your puppy.
It’s a really hard call to make, isn’t it – do we vaccinate knowing there’s a very small but real risk of side effects; or do we not and take the risk of a life-threatening (and contagious) infectious disease?
Personally, my dogs are vaccinated with the L4 vaccine because I’ve seen the effects of Lepto in unprotected dogs, but that doesn’t help when something does go wrong that seems to be linked to what we’ve done. Statistically the vaccine is very safe – but like any medicine, it’s not perfect. Don’t blame your yourself or your vet – this is a horrible thing but it’s not anyone’s fault. Rather it’s a tragic concatenation of circumstances that probably couldn’t have been predicted.
I would strongly advise that you get a formal autopsy performed to help determine exactly what went wrong, and forward the results to the Veterinary Medicines Directorate (the UK’s animal medicine and drugs regulator) so they are aware of what’s happened and why, and can work with the manufacturer to help improve the vaccine’s safety.
So sorry you and especially your dog went through this. All I can say is that the vet gives best advice based on the information they have. Even L2 vaccines carry a degree of risk and other dog owners will have had a similar experience to yours with that virus. I personally take medication which has side effects and risks. We have to weigh these up all the time.
Where I live there are increasingly wild boar encroaching on the areas I walk my dog so I will be taking the L4 vaccine as wild boar have been shown to carry the bratislava strain of the virus. It won’t be the same for other dog owners whose dogs are not exposed to that virus on a regular basis.
I pray my dog does not have an adverse reaction.
I hope your current pets are fit and healthy and stay that way.
If anyone’s interested in Leptospira bacteria in pigs, NADIS has a good article here.
I’m so sorry you’ve had this experience – losing a pet in such a horrible way is always awful. Although adverse reactions are really rare in practice, they’re awful when they do occur, especially when the reason for it isn’t entirely clear. I’m sure either your vet will have reported this to the VMD as a suspected adverse reaction, but if you’re not sure, you can submit a report yourself here: https://www.gov.uk/report-veterinary-medicine-problem/animal-reacts-medicine
Thank you for your information I am thinking of buying a puppy in the UK and I had notice that some of the breeders said they used the L 2 and not the L4 and I wonder what was the diffeance.
Thanks for the information very informative.
I do have a question though.
We have bought a boarder puppy that has his first set of injections which Included the L4 version.
We have taken him to our local vet for 2nd set of injections they have informed us they do not give the L4 version and have given the L2 version and have informed us he will need to go back in two weeks for another set of the L2 version?
Would this be correct or would this be in theory an overdose of the Lepto vaccination?
Any info would be appreciated
It depends on the exact license claims; most lepto vaccines are intercompatible so boosting L4 with L2 gives L2-level protection. However, there are a few manufacturers whose vaccines aren’t demonstrated to be itnercompatible with L4, so a new course is needed.
Thank you for your article which is very helpful. I have a question: is it not possible for manufacturers to develop individual vaccines for each illness, particularly for Leptospirosis, given spaced out, or would that be worse for the dog with more different shots and impractical for some owners and more expensive. If a dog was very unfortunate in having a reaction and any vaccines had been given separately, would this not make it easier to trace the component where the reaction had come from? Just a thought
It’s theoretically possible. However – most of the problems with killed vaccines come from the adjuvant, rather than the antigen, and you need almost the same dose of adjuvant for 4 antigens as for 1. So I doubt it would make much difference in practice!
Essentially, the L4 has 4 strains of Leptospirosis in it, compared to the 2 in the original L4.