Why Vaccine Hesitancy May Lead to More Infections in Pets

In my last article, we discussed the deadly viral disease Parvovirus. We looked at what the disease does to dogs, how it is diagnosed and treated, and how it can be prevented. We also asked whether cases of Parvovirus were increasing in the UK, and found that although Parvovirus cases may be lower than the public think thanks to a lack of understanding and media bias, lower vaccine rates have been shown to cause increased Parvovirus cases. So today we continue to discuss vaccinations in dogs, why some people are hesitant to vaccinate their dogs, and some of the myths surrounding this.

Vaccination Overview

In case you need a reminder, here’s a basic summary of what vaccines are.

To fight disease, the immune system needs to create an immune response made up of white blood cells and antibodies. If the body encounters a virus, bacterium, fungus or other organism it has no prior knowledge on, it takes time to process and develop an appropriate immune response. This delay allows the organisms to cause disease. If the disease is defeated, future immune responses to the same disease tend to be more effective as the body can ‘remember’ fighting it before. This is why the first incidence of a disease, like COVID-19 or chickenpox, is often more severe than subsequent infections.

A vaccine is a drug designed to create an immune response against a specific organism without causing disease

This means that the body is prepared and can rapidly fight the organism if it is encountered in the real world. This means the organism doesn’t have as much time to cause disease, so the symptoms of disease after vaccination are reduced or even eliminated entirely. An analogy would be a completely untrained person (not vaccinated) going to do a job (they will struggle, but perhaps learn on the job and eventually be successful) versus someone having lots of training first (vaccinated) then going to work (they will be much better prepared and more likely to succeed with less difficulty).

All vaccines contain part of an organism that the body can detect and create an immune response from. The way the vaccine utilises the organism determines the type of vaccine, and include: inactivated (dead organism), live-attenuated (weakened organism), m-RNA (code for proteins of the organism), or subunit/recombinant/conjugate (pieces of the organism).

The immune response created by a vaccine may last a lifetime, or require frequent renewals via booster vaccines, depending on the type. In the UK, it is recommended that all dogs receive vaccines protecting them against Distemper virus, Infectious hepatitis virus, Parvovirus and Leptospirosis bacteria – these are the Core Vaccines. Other vaccines may be recommended depending on lifestyle, or if they visit other countries.

Crucially, vaccinations do not just protect the individual, but the population at large

The more individuals that are vaccinated, the less able a disease is to spread. This means that individuals who are not vaccinated will be better protected the more people around them are vaccinated. This is called herd immunity. The World Health Organisation (WHO) recommends a 95% vaccination rate in a population for effective herd immunity against most (although not all) diseases.

There is overwhelming scientific evidence that vaccines are, on average, effective, safe, cost-effective, and good for humanity (as well as animals). In fact, thanks to vaccinations, we have been able to completely eliminate two diseases entirely – Smallpox in humans, and Rinderpest in cattle – and reduce mortality from some diseases dramatically (a 95% reduction in childhood deaths from measles, for example). Nevertheless, in recent years there has been a lot of misinformation and scaremongering surrounding vaccinations, both in humans and pets. We want to spend the rest of the article discussing this.

Vaccine Hesitancy

Vaccine hesitancy is the “reluctance or refusal to have oneself or one’s children [or pets] vaccinated against an infectious disease”. As far back as the 18^th century when the precursor to modern vaccination, variolation, was introduced in the West (a form had been practiced in China and India long before), there was opposition, primarily from religious figures. Throughout the history of modern vaccination there have been opponents arguing against compulsory vaccination, certain types of vaccines or even vaccines entirely. Despite this, opposition to vaccination was largely fringe scientific and medical opposition, with high rates of public vaccinations contributing to the enormous benefits listed above.

However, in recent decades, and especially since the 2010s, vaccine hesitancy has become more mainstream, more talked about and more popular. The ‘anti-vax’ movement has begun to put forward more political, social and economic reasons against vaccination, which medical professionals and politicians are finding harder to combat than medical arguments. Social media personalities, fringe doctors and even certain politicians have all been seen to question vaccinations. These social and political changes have been shown to increase the rates of infectious diseases worldwide, such as in the USA where the first cases of measles since 2000 have been seen, or in Samoa where a 2019 measles outbreak killed 83 people. The WHO has named vaccine hesitancy as one of the top 10 threats to global health.

Canine Vaccine Hesitancy

Recent studies have shown canine vaccine hesitancy, where owners are reluctant to vaccinate their dogs, is on the rise too (note that this doesn‘t mean all of these people will not get their dog vaccinated; some may be unsure or need convincing). An American study showed around 53% of dog owners have some degree of hesitancy, while 37% consider vaccines ‘unsafe’, 22% ‘ineffective’ and 30% ‘unnecessary’. Most concerning, 37% of owners believe vaccines could give their dogs autism – aside from the fact that we aren’t even sure if dogs can have autism, the myth that any vaccine causes autism has been proven wrong many times, with the doctor who first proposed this belief having his medical licence revoked after it emerged his research was fraudulent. Some more UK-centric data from the PSDA showed that pet vaccination has dropped from 84% in 2016 to 66% in 2019, and around a third of pets do not receive regular booster vaccinations. It has also been noted that those with reluctance for human vaccinations are more likely to be reluctant to vaccinate their pets as well.

It is difficult to prove a concrete link between increased cases of Parvovirus and other diseases, and vaccine hesitancy, but as figures showed in our previous article a lack of vaccination is seen alongside increased case numbers. It is therefore likely that increasing canine vaccine hesitancy has or will lead to increased cases of Parvovirus and other diseases, particularly if herd immunity has dropped below 95% of the population (which the PSDA data would indicate is the case).

We believe that although vaccine hesitancy should be addressed, people’s beliefs generally come from a place of concern and care for their dogs

Denigrating people will not increase trust. Some beliefs have some truth at their root, but the arguments are taken to the extreme. Instead, we believe education is the way forward, and hopefully this article will convince some of you to vaccinate your dogs if you were reluctant, or even to just have the discussion with your vet.

What Concerns People Who Are Vaccine Hesitant?

Let’s look into the most common arguments made by those who are concerned about vaccination.

Vaccines are dangerous or have significant side effects

It is commonly argued that vaccines are dangerous or have side effects. Hearsay and social media reporting can easily exaggerate this belief (such as the unnecessary controversy surrounding the L4 vaccine in the UK) and can quickly make vaccinating your dog seem like an unnecessary risk.

Vaccines are medications and like all medications do carry potential side effects

However, for the majority of dogs these are mild and short-term. These include pain on the site of injection, swelling, a mild fever, and inappetence. More serious side effects do occur, but are much rarer. Depending on the vaccine, these include vomiting, diarrhoea, lethargy, anaphylaxis and seizuring. In extremely rare cases, these have resulted in deaths due to complications. However, it is important to remember that the overall numbers of complications are very low, and there is evidence to prove this. A study in Japan of over 57,000 dogs found only 359 showed any adverse reaction (62.7/10,000), of which the majority were skin or gastrointestinal problems. One death occurred due to anaphylaxis, a rate of 1 dog in every 50,000 vaccines (and may well have been an outlier in this one study). This is tragic, but incredibly low and comparable to other vaccines used in humans. A myriad of other studies confirm similar rates. Compare this with the death rates for Parvovirus, for example, 70-90% if left untreated, and the risk-benefit should be clearer.

It should be noted that not all vaccine reactions are reported so the numbers may be underreported

It may also be the case that even those animals unwell enough to need a vet are still not reported as a vaccine reaction if the link is missed (though also consider that some dogs may have reported vaccine reactions when their illnesses are actually unrelated). Serious side effects are most likely to be picked up, however, and thus reported.

No medication is 100% safe or benign, but for the majority of the population of dogs, vaccines are much safer than the risk of being unvaccinated

This is particularly the case because the majority of vaccines are given to healthy animals, versus other drugs usually given to unwell patients. Please ask your vet about the specific risks to your dog, to ensure vaccination is right for them.

Vaccines are untested

It is not uncommon to hear that vaccines are untested, or not tested properly. This became particularly prevalent with the rapid development and release of various vaccines for COVID-19, which to many people seemed too quick to be safe. Although slightly outside the scope of this article, according to the British Society for Immunology, the reason why these vaccines were developed so fast was thanks to large scale collaboration and prioritisation during the pandemic, the fact that the science behind the vaccines was not new, large sources of funding from governments, rapid scaling up of manufacturing to meet demand, and a large number of volunteers – all these factors are not normally as prevalent as with normal vaccine development. The BSI emphasised that all COVID-19 vaccines followed normal safety procedures.

Okay, but what about normal vaccine development?

Even if it takes longer, what makes it safe? The University of Oxford outlines the various steps that a vaccine manufacturer must take to release a new vaccine. These steps can take years or even decades.

Firstly, research takes place, building on known science to explore if a vaccine can even be created. Scientists then perform tests with the possible drug ‘in vitro’, meaning on isolated cells. After this step, ‘in vivo’ testing in whole animals can begin, often mice. These steps are performed to demonstrate the product has the desired effect (creating an immune response) and is safe.

Testing on small groups under controlled conditions

In humans, testing begins once the above steps have been approved. Phase 1 involves a small group of voluntary humans, often around 100, to ensure the drug is safe to give to people and what doses are needed. Phase 2 involves several hundred people, checking the vaccine works routinely and to identify less common side effects. Finally, phase 3 requires several thousand volunteers to assess the level of protection in large groups, and rarer side effects.

In dogs, cats, and other animals, different approaches may be used, but the same principles apply: testing on healthy animals to check that the product is safe, and then measuring the immune response, and then trialling more widely, and carefully monitoring all the animals for both immunity and side effects. In some cases, it may require challenge trials, where dogs or cats that are believed to be immune are exposed to the infectious agent, to demonstrate that the vaccine does indeed protect them – this is especially important for diseases where antibody levels don’t give a reliable measure of protection.

During all stages scientists review the data from tests, check manufacturing standards and quality control, to ensure all stages of testing are performed correctly. Once all standards have been met, the relevant body approves the drug for use. For animals in the UK, this body is the Veterinary Medicines Directorate (VMD).

Licensing and release

After licensing, regular testing is continued (sometimes called Phase 4) and recording by doctors (or vets) is checked. This ongoing assessment can lead to improvements in the drug, changes to alter side effects, or even in some cases withdrawal of its use if it is considered not appropriate anymore.

Vaccine manufacture is as stringent as can be, and while errors and mistakes do occur, these are seen no more frequently as in any other important industry, such as food, construction and waste management (which thankfully are low).

Vaccines are ineffective, unnecessary or do not work

Some people claim that vaccines do not work properly, or are not even needed. It is harder to spot the absence of something, i.e: disease, than to spot its presence – what we mean is that when an animal is healthy, it receives a vaccine and continues to be healthy, how can we know the vaccine did anything? We know through both empirical evidence and actual testing that vaccines do work.

The effects vaccines have on immunity can be measured

When an animal encounters a disease, either the real thing or a weakened/dead vaccine, in most cases their antibody levels increase. These antibodies can be detected in the body – by measuring the antibody level before and after vaccination, a rise can be detected indicating the body is responding to the immune challenge of the vaccine, exactly what a vaccine is designed to do. Testing can be as accurate as measuring the specific antibodies for a specific disease. Vets can even use these tests to determine if a dog has been vaccinated, if it has been exposed to the real disease, and if their immunity is strong enough to give them protection from the disease.

We can also measure the overall incidences of disease to show vaccines work

We’ve listed many figures in this and the previous article that show disease rates increasing or decreasing alongside vaccination rates. And while correlation does not always equal causation, and other factors such as general health, hygiene and climate affect disease rates too, evidence is conclusive that the more people/animals are vaccinated, the less a disease is present in a population. The best examples of this are, again, the eradication of smallpox and rinderpest, something likely impossible without vaccinations.

Most of us in the developed world live our lives without ever encountering polio, measles, mumps, and of course smallpox, and sometimes this is taken for granted. But go to a less developed part of the world, or even ask elderly people or look through historical documents, and you will see how these diseases ravaged communities and ended lives. We should be grateful that the majority of us do not need to experience these diseases, and vaccinations are the main reason why.

Vaccines are there to make vets money

Something unique to the veterinary industry (at least in the UK where most human vaccines are free via the NHS) is the costs involved with vaccinating your dog. With inflation and the cost of living crisis showing no signs of abating, and more people struggling financially, many people question whether vaccines are just another way for vets to make money.

By now, we hope that the above arguments show why vets recommend vaccinations on the grounds of health

We want to protect your animal and the wider population. But let’s consider the financial costs. Vets have to charge for vaccinations, as well as all other procedures and drugs they provide because running a veterinary practice costs money. We’ve explained this many times before, but in short the bills must be paid, staff need money to live, equipment and consumables must be bought. Very little of what a practice makes is pure profit, and a lot of this will be reinvested into the business to improve it. The costs of vaccines help this.

Consider also that a vaccine appointment isn’t just a jab – it includes a healthcheck, time to ask your vet any questions about your dog’s care, sometimes extras like nail clips or anal gland expression. Vets are able to check your pets for disease that may be spotted early, or correct husbandry issues like weight gain before they cause problems.

Finally, although the cost of a vaccine may be a lot for some owners, the costs of treating a dog with Parvovirus will be considerably more, when hospitalisation, antibiotics, fluids, other drugs and ongoing care are considered. For some, this may be unaffordable, meaning euthanasia may be the only option left. Prevention is always better than cure, and this extends to finances too.

However, if you are really struggling to afford vaccinations for your animal, we would encourage you to seek help from the PDSA, the RSPCA or other local charities. Your vet may also offer health schemes that reduce the costs of vaccines. The costs of not doing so will be much higher, and could result in heartbreak.

Compulsory vaccination means too much government/legal control

In a world of increasing distrust in government and scientists, many people are concerned that mandatory vaccination is an infringement on individual freedoms or liberties. Again, these concerns were exacerbated by the COVID-19 pandemic where although vaccination was not mandatory, at some points those who chose not to become vaccinated had greater restrictions than those that did.

In the UK, there is no law mandating vaccination of children or of pets

A person can choose not to vaccinate themselves, their children or pets. In some countries, such as Italy, Slovakia and certain parts of the USA, children must legally be vaccinated or the parents could face legal repercussions, and the children excluded from schools. Most vaccine policies for pets only apply to those travelling, such as dogs requiring a rabies vaccination before entering the UK, which we would not consider mandatory, as it doesn’t influence your ability to keep a pet.

This debate is tricky to navigate

On the one hand we have the statist or socialist argument considering the needs of the population at large, implementing policies to ensure the majority are protected regardless of individual freedoms; on the other we have the libertarian argument favouring the individual, parental/owner rights, and the belief one should not be told what to do.

From a purely objective view, considering the population at large, this author argues in favour of mandatory vaccination schedules for children (and arguably for pets) as a means to prevent harm to those who cannot or will not become vaccinated. We know that widespread vaccination creates strong herd immunity, which reduces incidence of disease dramatically – for the slight infringement on the individual, this author believes the benefits to society at large are far greater.

Final Thoughts

Given that the UK currently has no plans to implement a mandatory vaccine policy for children, we see no sign of this being considered for dogs any time soon. Thus, the decision to vaccinate your dog remains yours to make – we hope that this article has helped convince you to do so, or even to have the conversation with your vet if you are still unsure. Remember, we are not trying to push unnecessary or dangerous medication onto your dog, and we aren’t doing it to make money – we offer vaccinations to protect your dog from the most dangerous diseases, like Parvovirus, and ensure they and other dogs remain healthy for life.