With the rollout of Covid-19 vaccinations in full swing, vaccines are a hot topic. Quite rightly we are all taking more interest in how they work, if they’re safe and if we should be getting them.

But how about our furry friends?

Welcoming a new puppy into your family is undoubtedly one of the most exciting experiences life has to offer. Understandably your main priority is looking after them and keeping them safe. It’s worrying to know that they could get poorly. 

The good news is that vaccines to protect your new puppy have been in use for many years. The general consensus from the veterinary profession is that disease prevalence has fallen since their routine use in the UK dog population.

This article aims to delve a bit deeper into the science behind these vaccines, and how effective they actually are. This should allow you to make an informed decision when you bring your new family member home. We hope you will feel reassured that they are a proven way to help keep your pet healthy. But any specific concerns should always be discussed with your veterinary practice. 

What diseases do we vaccinate against?

The course of puppy vaccinations recommended by most vets contains protection from four key diseases: 

  1. Canine Distemper Virus
  2. Canine Hepatitis Virus (also known as canine adenovirus)
  3. Parvovirus 
  4. Leptospirosis 

These are also known as ‘core’ vaccinations because it is recommended that all dogs in the UK receive them. Globally this can vary slightly, due to the prevalence of other diseases. For instance, in the US the DHPP vaccine is much more widely used (and DHLPP), which covers parainfluenza.

So why does my puppy need to be vaccinated against these diseases?

The main reason for this is that, unfortunately, they can all cause severe illness and are often life-threatening. Leptospirosis is also zoonotic ,which means the infection can be passed to humans. This puts owners at risk of severe illness also. As a result, it is considered that prevention via vaccination is the best method of dealing with these diseases. Treatment won’t always guarantee recovery. 

Crucially, you won’t always be aware that your puppy might be at risk. These diseases can survive in the environment or be spread by wildlife.

An additional vaccine also exists against ‘kennel cough’. This includes protection against both parainfluenza virus and the bacteria Bordetella bronchiseptica, which both cause upper respiratory tract signs such as a cough. It is often classed as a ‘non-core’ vaccination as both diseases rarely cause serious illness in young healthy animals.

However, both these diseases are highly transmissible and can spread rapidly between groups of dogs in close contact; for example, at daycare facilities or boarding kennels. The decision to use this vaccination should be made on a case-by-case basis. So it is worth discussing your individual circumstances with your vet.

How do vaccines work?

The overall aim of a vaccine is to prevent your pet from getting ill for the targeted disease. It does this by deliberately exposing the immune system to a small amount of the disease-causing agent in a harmless form. This prompts your body to react and produce antibodies to fight it off.

Although not necessary this time around, these antibodies remain in your immune system’s memory and can be quickly produced next time the disease is encountered for real. This means you remain one step ahead of the virus or bacteria. Essentially you have a head start compared to someone who is naïve (hasn’t had the vaccination) and therefore your immune response will be immediate and more effective.  

Depending on the specific disease and vaccination in question they protect us in several ways. Most vaccines aim to prevent mortality and clinical signs, so essentially you won’t get ill or die from the disease. Some vaccines, such as the kennel cough vaccine, are designed to reduce clinical signs. So while your pet may still get a cough if they’re vaccinated, they are unlikely to get seriously ill. This is similar to the human flu vaccine.

The final function of some vaccines is also to reduce the amount that an infected animal can shed the disease. This is crucial for preventing these diseases from spreading through entire populations and means outbreaks are a lot less likely and easier to contain. 

What does the vaccination process involve?

The standard ‘puppy course’ of vaccinations involves two vaccines given between 2 and 4 weeks apart. Puppies are usually aged between 6-10 weeks for the first vaccine and 10-12 weeks for the second. Your puppy is then usually fully protected within 1-2 weeks after the second vaccination. Some variation exists between different vaccine manufacturers so your vet will advise the correct protocol based on the brand of vaccine they use. 

After this initial course an annual booster is required to maintain immunity. In the first year all diseases are vaccinated against again, but after this, not every disease requires an annual booster. As the duration of immunity varies between them, while some will only need repeating every 3 years, the vaccine for leptospirosis requires annual ‘topping up’. As a result your dog will require a booster appointment every year, but your vet won’t always be giving the same vaccine. This yearly appointment is also important as a general health check. 

How do we know they’re safe?

Pharmaceutical companies who develop these vaccines have to conduct extensive research and rigorously test the products, and present all the data to the regulator before they can be certified for use. This ensures that they’re not only effective but also safe. 

These studies involve giving animals the vaccine and measuring the level of antibody production to ensure that the desired immune response is produced. In some cases they also then expose these animals to the disease to confirm that they do not get poorly. Any side effects are reported too to confirm the safety of the product. The vast majority of vaccine companies report anaphylaxis occurring in less than 0.01% of cases, which equates to at most 1 animal in 10,000 treated. 

How do we know they’re effective?

When the correct vaccination protocol is followed, and annual boosters are kept up to date, manufacturers report incredibly high levels of protection. 

One of the leading vaccine manufacturers, Nobivac, reports a protection level of 99.5-100% against clinical signs of leptospirosis, including mortality, following the puppy vaccination course. Similarly reassuring figures were reported for the distemper, hepatitis and parvovirus vaccination. Studies showed a 100% protection level was still present up to three years following second vaccination.  

Another way of assessing the efficacy of puppy vaccines is to look at the level of these infections in the UK dog population. Any vet that has worked in the UK for a long period of time will tell you how frequent both distemper and parvovirus outbreaks were. While cases are still seen, they are far less frequent than they used to be and this is largely attributed to widespread vaccination.

What about herd immunity?

A report in 2020 by the PDSA revealed that over 80% of dogs in the UK are vaccinated as puppies and continue to receive boosters as adults. This results in herd immunity, which provides indirect immunity for unprotected individuals by the very fact that the majority of the population is protected. 

The effectiveness of a vaccine also relies on the appropriate timings being adhered to and that the animal is fit and well at the time of vaccination. Concurrent illness or medications can alter the immune response. 

While none of us wants to be over-vaccinating our pets, the consequences of not vaccinating can be so severe that it is vital that any decision not to vaccinate is a fully informed one. As vets, we are not only qualified independent advisors, we also have your pet’s best interests at heart and are always happy to collaboratively discuss your individual circumstances so that we can give tailored advice to keep your pet as safe as possible. 

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