A study released last fall indicates more than 37 percent of dog owners believe that canine vaccinations could cause their pets to develop autism — a belief that animal health experts say is wrong on several levels.
Published in the online journal Vaccine, the study “Sick as a dog? The prevalence, politicization and health policy consequences of canine vaccine hesitancy,” found that more than half of the country’s dog owners have some level of anti-vax feelings when it comes to their pets.
It’s leaving veterinarians in Maine frustrated by clients who refuse the important medical care for their pets.
The link between human vaccines and the onset of autism has been disproven by peer-reviewed scientific studies, and there is no scientific evidence that domestic pets can have autism, vets said.
“I have never heard of autism in dogs,” said Dr. Kate Domenico, president of the Maine Veterinary Medical Association. “How would you assess your dog? I would love to know exactly how you would classify your dog as autistic.”
Vaccine opposition is nothing new, although it’s better known when it comes to humans. But it’s picking up steam, according to a 2023 study on human attitudes toward vaccines published in The Lancet, and it’s bringing pets along for the ride.
The study was presented to The Lancet Commission on Vaccine Refusal, Acceptance, and Demand in the USA, co-hosted by the Yale Institute for Global Health and the Baylor College of Medicine. The authors, who are all members of the commission, said that over the last 20 years, the human anti-vaccine movement has evolved from what it termed a “fringe subculture” into an increasingly organized network.
The study’s authors said the anti-vax movement has grown to the point it is having negative impacts on public health, such as the return of whooping cough and measles — both illnesses that were essentially eradicated by vaccines until recent years.
The same anti-vaccination attitudes that brought back measles are spilling over into domestic pet care, according to animal health experts.
The dog study pointed to the explosion of human vaccine mistrust during the pandemic. That mistrust created what researchers call a “spillover effect” to domestic pet vaccinations, according to the study.
Hesitancy or outright refusal to have pets vaccinated is nothing new, but the growing number of people opposing dog and cat vaccines nationwide is cause for concern, according to animal health experts in Maine. Besides animal owners’ concerns about autism, other factors that play into their decisions to not vaccinate pets include access to veterinary care and financial constraints, Domenico said.
In the “Vaccine” study, researchers found that 45 percent of U.S. households own dogs. Of those, close to 40 percent believe that canine vaccines are unsafe, more than 20 percent believe these vaccines are ineffective and 30 percent consider them to be medically unnecessary.
It’s a trend veterinarians in Maine would like to see reversed.
“Vaccines do indeed strengthen immunity against potentially serious or even fatal diseases, especially when exposure to other animals occurs, such as in boarding kennels, pet shops, animal shelters or shows,” said Robert Causey, DVM, associate professor of animal and veterinary sciences at the University of Maine. “Vaccines also provide protection against wildlife-borne diseases, such as rabies, and environmental disease such as tetanus.”
It’s not unheard of, but it is extremely rare for a vaccinated dog or cat to contract rabies, according to a published study by the American Veterinary Medical Association.
The research showed that out of 1,100 reported cases of canine and feline rabies in 21 states, the majority of the animals — 97 percent — had not been vaccinated. The remaining 3 percent had a history of rabies vaccinations.
In its most recent numbers, the Maine Centers for Disease Control reported 30 cases of rabies in the state in the first half of 2023. All cases were found in small, wild mammals.
Because domestic animals can serve as a bridge between wildlife rabies reservoirs and humans, vaccination of pets is one of the most effective public health tools available to protect human health, according to the World Health Organization.
Getting pets vaccinated against rabies is a tough sell when owners come in armed with erroneous information they heard from well-meaning people who regularly work with pets like groomers, breeders and pet shop employees, Domenico said.
She has had clients come in repeating wrong information gleaned from the pet industry, such as their particular breed of animal does not require any vaccines or does not need them until they are 6 months old.
Neither is ever the case, she said.
Veterinarians agree some pets may react to vaccines, much like humans react to their annual flu shots. In both cases, there’s no reason not to be vaccinated.
“All vaccines can pose some degree of risk, but this is where a conversation with one’s local veterinarian can be very helpful,” Causey said. “One can have a discussion, based on the pet’s age [and] lifestyle, which vaccines are necessary to protect against severe disease, and which may be considered elective.”
Those electives, also called non-core vaccines, include bordetella, leptospirosis, Lyme disease and influenza for dogs and feline leukemia for cats.
“I have seen dogs who have died of kidney disease because their owners refused to get them vaccinated for leptospirosis,” Domenico said. “It did not have to happen.”
Leptospirosis is a deadly bacterial disease most commonly spread through the urine of wild animals. So if a pet drinks puddle water out in the Maine woods, it could easily be exposed to it.
Non-elective or core vaccines are rabies and distemper, and are required by law in Maine.
To further reduce risk of a reaction, Domenico said pet owners can opt to spread individual vaccines out over a period of time.
“Every veterinarian should evaluate every patient to determine whether or not that pet needs those non-core vaccines,” Domenico said. “It should be based on risk of exposure.”
