Why dogs and cats need booster shots

Derri Dunn
25 February 2022 - 8 min read
A cat being vaccinated

The pandemic has had a worrying effect on pet vaccinations in the UK. The 2021 PDSA Paw Report showed that primary vaccinations were lower in May 2021 than in February 2020. The percentage of pets regularly vaccinated had also declined.

With 23% of dogs and 39% of cats not receiving regular boosters, that’s 6.4 million pets in the UK that are currently unprotected by vaccinations.

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Dog and cat
Dog and cat

Vaccine hesitancy among pet owners

There are four main reasons for a lower booster uptake among pet owners:

  1. Vets having to ‘catch up’ missed vaccinations during the lockdowns and prioritising certain vulnerable groups of pets – mainly initial courses for puppies and kittens.
  2. The increase in pet ownership during the pandemic causing a rise in demand and subsequent shortages.
  3. This supply and demand pushing up prices to levels that some owners will be reluctant to pay.
  4. Owners reluctant to vaccinate due to safety concerns.

Supply issues are expected to even out through 2022.

Justine Shotton, president of the British Veterinary Association says: “Vets are working with vaccine suppliers and may need to prioritise allocations. Your vet may be in contact if delays are likely, but we’d like to emphasise that a short-term delay shouldn’t be cause for concern for either pet or public health.”

So if you’ve had to delay your pet’s booster, now’s the time to contact your vet and get them booked in.

If price is a concern, you can find out the average cost of vaccinations for cats and dogs near you. Delaying boosters to save money is unwise. It could mean having to pay more for your pet to have the initial course of injections again, which will cost more in the long run.

But what about owners who just don’t believe pet vaccines are safe, or that boosters aren’t necessary because their pet will still have immunity from previous vaccinations?

What vets and experts say about boosters

All expert UK veterinary organisations, including the British Veterinary Association, PDSA, Veterinary Products Committee, Veterinary Medicines Directorate (VMD) and British Small Animal Veterinary Association (BSAVA), believe vaccinations are safe and help save millions of pets' lives every year, both directly and through herd immunity.

But a previous PDSA PAW Report in 2019 expressed concern about the growth of an anti-pet-vax movement and said that increasing concerns about over-vaccination are resulting in fewer people vaccinating their pets regularly, which could weaken pets' herd immunity in the UK.

In 2020 The VMD echoed these concerns. “In dogs and cats, diseases that were once chronic scourges have now become relatively rare in the UK. As the public memory of the consequences of these diseases fades so the rationale for routine vaccine programmes is increasingly questioned,” it says.

“A healthy debate of the pros and cons of vaccination is valuable as it is entirely possible that a disease can become so rare that risks associated with vaccination can outweigh the risk of contracting the illness. However, such events are rare and likely to remain so as world-wide travel of people and their pets increases.” 

 And it’s not just animals that are at risk from low pet vaccine uptake. "Some diseases that our pets carry can be transmissible to humans, so vaccination can be an important factor in protecting your family," adds Vet Sophie Bell.

Dog and cat vaccines are safe

"You may have found reports online of some worrisome reactions that have been observed by vets following a vaccination,” says Dr Bell.

For example, in 2016 reports circulated on social media about dogs suffering serious side effects after receiving the new L4 leptospirosis vaccine.

The Government’s Veterinary Medicine Directorate (VMD) responded by pointing out that there were fewer than seven adverse reactions per 10,000 doses of L2 and that even this tiny figure includes every suspected adverse event reported, even cases that were considered unclassifiable or were later found to be unrelated to the vaccine.

“The overall incidence of suspected adverse reactions for both L2 and L4 vaccine products is therefore considered to be rare,” Concluded the VMD.

Even where adverse reactions do take place, most aren’t serious.

“Like with any veterinary medicines, there will always be side effects observed,  and they’re graded from mild to severe, says Vet Sophie. “Vaccinations, thankfully, carry only a very small adverse reaction risk. Most reactions observed have no long-lasting side effects."

Pet vaccination side effects are rare and usually mild

Puppy and dog vaccination side effects in the UK are unusual.

In its 2020 Position Paper on Authorised Vaccination Schedules for Dogs, the VMD says that between 2000 and 2020 over 166.8 million doses of dog vaccines were sold with adverse events reported in just 0.0213% of these.

Some of these adverse reactions are likely to be ‘coincidental’ and may not even be related to vaccination.

An adverse even could be anything from redness or swelling, right up to death, but the majority will be mild reactions.

Spot the signs of vaccine side effects

Serious vaccine side effects in cats and dogs are very rare. Mild reactions can include loss of appetite, decreased activity, mild fever, sneezing, coughing or a runny nose.

A small, firm swelling may develop where the shot was given but should disappear a few days later. If it doesn’t and gets bigger, contact your vet.

"Once your pet receives their first vaccine, be sure to monitor them for the rest of the day,” advises vet Sophie Bell. “Make sure you know what to look out for if they're having a reaction such as increases in vital signs – temperature, pulse and respiration rates – and also monitor their food and water consumption, note any behavioural changes and report anything abnormal to your vet.”

  • More serious vaccine side effects include:
  • Vomiting and diarrhoea
  • Collapse
  • Difficulty breathing
  • Severe cough
  • Hives

If your pet experiences any of these, seek immediate veterinary help.

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Video vet

Are we over-vaccinating our pets?

Because vaccines have a long duration of immunity (DOI), some pet owners question whether yearly dog and cat vaccination is really necessary in the UK. Some have concerns that we are over-vaccinating our pets.

 Over-vaccination is when:

  •  Pets that are already immune to something are vaccinated against it again while they still have immunity
  •  Pets are vaccinated against diseases they aren’t at risk from

Back in 2003, Ronald Schultz, professor and chair of pathobiological sciences at University of Wisconsin School of Veterinary Medicine, said that although he believed core vaccines are essential for dogs, the type of vaccines needed and their frequency depends on environmental factors and way of life. 

His research relates to dogs in the US which are  routinely vaccinated for rabies and Lyme disease. He suggested that dogs should receive a rabies vaccine every three years and other core vaccinations no more often than every three years.

For non-core vaccines like Lyme disease, he recognised that annual boosters were necessary, but not all dogs would need them as their chances of exposure to the disease are very low. He warns that over-vaccination for Lyme disease can cause mild arthritis, allergy or other immune disease.

In its most recent vaccination guidelines The World Small Animals Veterinary Organisation (WSAVA) acknowledges that newer vaccines have a longer duration of immunity and says that “we should aim to reduce the ‘vaccine load’ on individual animals in order to minimise the potential for adverse reactions to vaccine products and reduce the time and financial burden on clients and veterinarians of unjustified veterinary medical procedures.”

It says vaccination guidelines are now based on a “rational analysis of the vaccine requirements for each pet”

Here in the UK, vets follow guidelines to tailor a vaccination program to an animals individual risks and vulnerability. For example, dogs aren’t routinely vaccinated for Lyme disease because they’re not considered to be at general risk of exposure. A kennel cough annual booster might be offered, but only of your dog goes to daycare or boarding kennels.

So although you might be taking your dog or cat for a booster appointment every year, vets follow constantly evolving guidelines which should mean your pet’s only receiving the vaccinations they need. For most this is every three years for core vaccinations and annual boosters for things like leptospirosis or rabies if needed.

Titre testing: an alternative to boosters?

Some pet owners and vets reduce the number of booster vaccinations their pets have using a type of blood test called titre testing.

A titre test can indicate whether your pet has has antibodies for a particular illness, indicating existing immunity to a disease.

Although it might reduce the number of boosters needed, it’s not a replacement for your pet’s initial vaccination course.

But, says vet Sophie Bell, "Some individuals choose to titre test following these primary core vaccines. This involves a simple blood test to look for the antibody levels. If they are moderate to high, vaccination may not take place that year but if they are low a booster will be needed.”

There are some significant disadvantages and limitations of titre testing: 

  • It’s likely to be more expensive than a booster, so it’s not an alternative for owners simply looking to save money on boosters they don’t need. An annual titre test cost around £100. You might need to pay your vet’s consultation fee on top of that. In December 2021 we found that the average cost of a dog booster including kennel cough was £64 in the UK.
  • You might also need an up to date vaccination card when you go on holiday. "Some boarding kennels, won’t board your dogs based on a titre test alone. They often require full vaccination history,”  warns Sophie. If you bring your dog on holiday abroad with you, you’ll also need an Animal Health Certificate with an in-date rabies booster.
  • There’s disagreement in the veterinary world about whether titre testing is a good measure of immunity. Some say that a high antibody immunity doesn’t necessarily mean adequate cell immunity.

Because of that, most vets use titre testing instead to offer reassurance that a vaccine has worked, for example in an immunocompromised animal. It can also be used to avoid over-vaccination for animals with an uncertain vaccination history, for example a rescue dog.

Vaccines and pet insurance

Your pet insurance won’t pay for your pets to be vaccinated or to have their boosters – it’s a routine pet healthcare cost that you have to pay for yourself, like neutering or teeth cleaning.

Although it helps protect vulnerable pets through herd immunity, there are currently no pet laws in the UK saying you must legally have your pet vaccinated.

But what about if your pet catches a disease that could have been prevented by vaccination? Will your insurance pay for their treatment?

Pet insurers have slightly different vaccination requirements but all of the companies in our list of the best dog insurance providers say they will refuse to pay a claim that's the result of a pet getting ill or dying from an illness that it could have been vaccinated against if you haven’t kept up with its schedule of boosters.

So not vaccinating your pet might invalidate your pet insurance policy, as well as putting your pet at risk of contracting diseases.

ManyPets' view on vaccinations

As an insurance provider, we also believe your own vet knows best, so we will still cover your pet if your vet has recommended that they don't get vaccinated.

Most pet insurers require pets to be vaccinated against distemper, hepatitis, leptospirosis and parvovirus for dogs and feline infectious enteritis, feline leukaemia and cat flu for cats.

We understand that you might have concerns about vaccines but based on scientific data and research, we feel vaccinations are key to keeping pets healthy and preventing the spread of illnesses that can cause pain and suffering.

That's why we encourage pet owners to vaccinate their pets and follow the guidelines set out by their vets and relevant authorities.