What is herd immunity, and how does it apply to dogs?

When you hear the phrase “herd immunity” for the first time, the image that almost certainly comes to mind for most people would be a field of cows; because this is what we tend to think of as a herd!

However, herd immunity is a universal concept rather than something species-specific to cows and other herd animals, and it applies to dogs as well.

If you own a dog in the UK, they benefit from the advantages of herd immunity; and if your dog is vaccinated against contagious health conditions and up to date with their boosters, they’re actually doing their part to contribute to the herd immunity of the dog population in your local area and the country as a whole too.

If you want to know what herd immunity means, how herd immunity relates to vaccinations and how herd immunity applies to dogs, this article will give you the answers.

Read on to learn the basics of herd immunity for dogs, and how your dog can play their part.

What is herd immunity?

Herd immunity means that if the vast majority of a population are immune to a specific contagious condition, the other members of the population who are not immune to it are at lower risk of catching it in their turn.

The concept of herd immunity is scientifically proven; it is a factual process rather than a theoretical concept, and the term has been in common use since the 1920s.

Herd immunity occurs because if a population has a large number of members that are immune to the contagious condition in question, this serves as a break in the chain of potential infection, which in turn serves to reduce the chances of non-immune members of the population being exposed to and catching the disease themselves.

The more members of the population in question that are immune to the condition, the lower the chances of non-immune members being exposed to and catching the condition.

Over the long term, effective herd immunity actually eliminates the contagious diseases it applies to from the population in question entirely; be that a local population or even worldwide. This happened in practice in the human population in 1977, with the eradication of smallpox!

Herd immunity only applies to contagious conditions, meaning those that are spread from individual to individual. Also, herd immunity applies to individual, specific named conditions and the level of immunity any “herd” or population has to any given condition can be variable. However, herd immunity doesn’t apply to infectious conditions that are not contagious; and so does not apply to conditions like tetanus.

Herd immunity and vaccination

Herd immunity can be either a naturally occurring phenomenon, or triggered by, enhanced and greatly expedited by vaccination.

Natural herd immunity can be achieved in populations where animals become immune to a condition after exposure and recovery from it, and herd immunity can also be brought about or sped along by vaccination.

This means that herd immunity is not necessarily related to vaccination in every possible usage of the term, but when we talk about herd immunity and the dog population of the UK, we’re referring to a type of herd immunity that is instigated by widespread vaccination protocols.

How does herd immunity apply to dogs?

The vast majority of dogs in the UK today are vaccinated as standard against several contagious canine health conditions, which are considered to be widespread enough, serious enough, and contagious enough to pose a significant threat to the dog population as a whole, and individual members of the species.

The vaccinations we use as standard in the UK for dogs are not the same as in every other country, where the main contagious threats may be different.

How does vaccinating your dog serve herd immunity?

Assuming that the majority of the dog population in any given area are vaccinated and so, immune from certain contagious diseases, this means that any other dogs in the area who are not vaccinated and so, not immune, are less likely to contract such diseases themselves.

This is because their chances of being exposed to other dogs that are affected by or carriers of one of the conditions in question is much lower.

This means that if your own dog is fully vaccinated and up to date with their boosters, this not only means that they themselves are protected against certain diseases, but are also helping to contribute to the health of the canine community as a whole by protecting others who are not vaccinated.

How do unvaccinated dogs benefit from herd immunity?

If a dog is unvaccinated against a specific contagious canine health condition and does not otherwise have any immunity to it, their chances of catching it if exposed to it are very high.

However, whilst herd immunity doesn’t lessen the chances of such dogs becoming ill if they are exposed to the relevant contagious condition, it does lessen the chances of them becoming exposed to the condition in the first place; and if they’re not exposed to it, they can’t catch it.

Why might a dog be unvaccinated?

Puppies cannot be vaccinated until they reach a certain age, and until they have had their initial courses of vaccination, they are very vulnerable to contagious diseases.

Additionally, some dogs react badly to vaccination to the point that vaccination poses a great enough risk to their health that it is not appropriate for them.

Some health conditions and other problems may also make vaccination legitimately unviable for some dogs.

There are also of course irresponsible dog owners who don’t care enough about their pets to vaccinate, or don’t want to pay for vaccination. Finally, there are of course also some irresponsible dog owners who style themselves as “anti-vaccers” or that claim that homeopathy or other completely unproven or even outright disproven pseudoscientific approaches make vaccination against their beliefs.

If you’re considering going down such a route yourself, please do your research, fact-check everything, check the veracity of your sources… and make an informed choice about the risks your taking with your dog’s health if you apply your own anti-vaccer principles to a pet that gets no say in the matter.

One final note – if you know or come across any pet anti-vaccers online or in the real world whilst researching herd immunity and vaccination, you’ll probably hear lots of claims from people stating that they’ve never vaccinated a single pet (or used a homeopathic placebo or alternative) and none of said pets ever caught a disease, as justification for their stance or “alternative” healthcare provision.

This can be very persuasive, particularly if someone is trying to use it to encourage the use of a placebo or alternative to medically proven veterinary vaccination – but in reality, what is keeping their pets safe is actually herd immunity, and the vaccination of other dogs!