With the Covid vaccine programme for people rolling out, now seems to be the perfect time to talk about vaccination in cats, too. On our vet panel today, we have Lawrence Dodi BVSc MSc MRCVS, Rebecca Martin BVSc CertSAM MRCVS, Rachel Nixon BA VetMB CertAVP MRCVS, Laura Waring BVetMed MRCVS, and (asking the questions!) me, David Harris BVSc PGCert VetEd FHEA MRCVS.

Now that’s a lot of letters after peoples’ names, but we’re all vets in different fields of practice, from clinical practice to academia and industry, and we’re going to be looking at what vaccines a cat in the UK really needs.

Is pet vaccination really important in a modern, fairly hygienic, western country?

Lawrence: Even in western countries, the diseases we vaccinate for are still present, with certain geographic areas within countries having higher cases of different diseases. Because the diseases we vaccinate for aren’t visible and you don’t need to have your pet come in direct contact in many cases to catch the disease, the apparent hygienic state of where you live is only a false sense of safety.

Rebecca: Absolutely. Vaccinations only work to prevent disease outbreaks, if a sufficient number of the population take them up. This is the principle behind “herd immunity.” 

David: That’s key isn’t it. With so many “free roaming” cats, it’s even more important in this species to make sure that as many pet cats as possible are vaccinated. To be honest, I think infectious disease is a lot more common in cats than dogs: because they’re generally out and about, socialising unsupervised with other cats, much more often than dogs are. And because we have a much bigger stray cat population compared to the very limited numbers of stray dogs in most areas, there are reservoirs of infection that we don’t get to vaccinate.

What vaccines do you recommend for cats, and why?

Lawrence: I vaccinate my own cats for “cat flu”, enteritis and leukaemia viruses. My cats get into enough trouble as it is with other cats in the neighbourhood without worrying about what they might pick up from them. Just like with dogs, certain diseases we vaccinate for in cats don’t require direct contact or for them to be bitten.

Rachel: I would recommend that all cats receive their ‘core vaccinations’, regardless of whether or not they go outside. These viruses are highly contagious and can be carried on owner’s clothing meaning that even indoor-only cats are at risk.  In the UK core vaccinations protect cats against cat flu (caused by feline herpes virus and feline calicivirus) and feline enteritis. 

Rebecca: All cats in the UK should receive vaccinations against the two forms of cat flu (feline herpes virus and feline calicivirus) and feline infectious enteritis / panleucopenia. For cats that are outdoor cats, feline leukaemia virus is also recommended since mixing with other cats constitutes a potential route of infection. 

Laura: The core vaccination I recommend for cats protects against calicivirus, herpes and panleucopaenia. These infections are in some cases life threatening and can cause serious or chronic infections. Infections with these viruses are commonplace in the UK, and therefore any unvaccinated cat is at serious risk of contracting the illness. 

David: It’s probably worth remembering that vaccine schedules in cats are a little bit more complicated than in dogs…

Vetster option 01 (Blog)

Rebecca: As with dogs we now, beyond one year of age, typically rotate the components of vaccination, only administering as required. Whilst cat flu is still recommended to be given annually, we protect against enteritis and leukaemia triennially, since longer protection than one year, has been proven to exist.

David: And even for cat flu, there is evidence of some, limited, protection beyond 12 months. However, if your cat is going outdoors and meeting other cats it probably won’t be enough. But for indoor-only cats who are only exposed to cat flu viruses (herpesvirus and calicivirus) second hand, every other year or even every three years might be sufficient, in some cases. 

Lawrence: If you have a completely indoor cat with no other cats that can go outside, then a different approach to vaccination may be appropriate. It is best to speak to your regular vet to discuss the risks. I know many clients who still vaccinate in case their cat happens to get out or they bring something home with them on their clothing.

Are there any extra vaccines you might recommend for some cats? 

Lawrence: Not routinely unless owners are planning on taking their cats abroad and require rabies vaccination.

Rebecca: Not usually in the UK no. Some breeding establishments or catteries may include a vaccination against Chlamydophila felis since this pathogen can cause infertility and reproductive issues, albeit this is not commonly performed.

David: I think I’ve only ever administered a Chlamydophila vaccine to cats in breeding colonies – it’s definitely not a routine one.

Rebecca: Intranasal vaccination against the same bacterial respiratory pathogen that causes kennel cough in dogs (Bordetella bronchiseptica) is also possible, albeit rarely undertaken.

Rachel: ‘Non-core vaccinations’ that I give to certain cats include Feline Leukaemia virus – I would recommend this for all cats who go outdoors or are in contact with cats who go outdoors. The virus does not live long outside of a cat’s body, so transmission typically occurs directly between cats (particularly grooming/fighting). 

David: I think Lawrence and Rebecca – and many other vets – would call that a core-vaccine for the UK, actually. It’s really nasty but very preventable.

Rachel: Cats infected with the disease are at a high risk of developing severe illnesses such as immunosuppression, anaemia and cancer, and 80-90% of cats die within 3-4 years of diagnosis. 

Vetster option 02 (Blog)

Laura: In order to decide on the right vaccination protocol for the cat I would have a discussion with the owner to find out about the number of cats in the home and the cat’s lifestyle. For larger cat households or breeding colonies vaccination with feline leukaemia is also advised. Vaccination against feline leukaemia is also recommended for cats who have access to the outdoors as they could encounter cats with the infection. 

Rachel: Rabies is not currently present in the UK, so vaccination is not needed for cats in the UK. However, it is a legal requirement for pets travelling abroad.  

David: Interestingly, I don’t think I’ve ever done a rabies vaccine in a cat – dogs, loads of them, but I think fewer people take their cats on holiday with them. But that might be a whole other panel discussion!

Are cat vaccines safe – how many reactions or side effects have you seen?

Lawrence: I have seen one cat that developed a transient area of hair loss where the vaccine was given. However, it was unclear if it was a direct result of the vaccine or due to the cat over grooming the vaccine injection site. Regardless it regrew after several weeks.

Apart from this I have been fortunate in seeing no vaccine side effects. Just like with dogs, vaccine reactions are reported in cats but they are rare. This makes them much safer than what can happen if your cat were to contract the disease we are vaccinating for.

Rachel: Although severe vaccine reactions (breathing difficulty, collapse) are reported, I have never personally seen a cat have this sort of reaction. Occasionally some cats are slightly quieter than normal or have a reduced appetite for a few days, or develop a small swelling at the vaccine site which typically resolves without treatment.

Rebecca: Yes, in my opinion cat vaccinations are safe. I have seen very few reactions in cats and fortunately these have been typically mild, consisting of temporary inflammatory nodules, that subsequently disperse and disappear over a 2-3 week period.

Laura: Vaccines are very safe because of the vigorous clinical trials they undergo prior to be approved for use. This gives us confidence that not only are they safe but they provide good protection against the infectious disease which we want to prevent. In over 11 years as a vet I have only seen one acute reaction to a vaccination, this was in a young kitten. The kitten responded excellently to immediate treatment and suffered no long-term effects. Aside from this one case I have known a very small number of mild reactions such as a raised temperature, lethargy or inappetence. As a general rule most owners report to me that they have not noticed any side effects from the vaccination. 

David: There’s a lot of concern these days about FISS – Feline Injection Site Sarcoma.

Rachel: Feline injection site sarcoma is a very uncommon tumour in cats. Although the cause is unclear, it typically occurs at sites used for vaccinations in cats, and it has been suggested that inflammation at the injection site may become cancerous in some cats. This is extremely rare and I have only ever seen 1 case. 

David: Yes, like you I’ve seen one case, and the cat in question had quite a complicated medical history, so deciding on what the exact trigger had been wasn’t possible. It’s interesting though that most of the concerns over FISS come from the US, and studies suggest that they do seem to see the condition rather more frequently there than in the UK.

There’s some evidence now suggesting that any injection can trigger a FISS, so perhaps we’re unfairly pinning it on vaccines… Nevertheless, my personal preference is to use a non-adjuvenated vaccine in cats where possible, just in case.

There are lots of people who are worried about possible side effects from vaccination. Is there anything you’d like to say to them?

Rachel: I regularly see patients infected with diseases we can vaccinate against, and despite treatment not all of these survive, whereas I can think of only a handful of patients in my career who have developed a significant vaccine reaction. I would urge all pet owners to ensure that their pets are fully up to date with their vaccinations to keep them as safe as possible from preventable disease.  

Rebecca: As a pet owner myself, I completely understand that people worry for their pet’s health. Clearly, vets and owners alike, all have a common goal to do what is best for their patients/pets. In the human field, certain vaccinations were historically given a bad press, and even though many initial claims associated with them were subsequently refuted, I feel that the “mud” somewhat stuck regardless! Vets have also in the past, been accused of “over-vaccinating” pets every year, with all vaccine components being given, or not tailoring vaccines to each individual animal. 

David: Hear, hear! 

Rebecca: With the advent of triennial vaccinations and consideration of each and every pet’s personal lifestyle and associated risk factors, I do feel we are in a good place right now as regards vaccination for pets. Vaccines undergo rigorous safety and efficacy trials and by using them appropriately, we can prevent fatal diseases, which previously posed a significant health risk to our UK pets. 

David: I’d absolutely agree. Cats are prone to some really nasty infectious diseases, and vaccination is by far the safest way to prevent them and keep your cats healthy and happy.