Nearly half of dog owners are hesitant to vaccinate their pets, finds study

A new study has found that US dog owners who harbor mistrust in the safety and efficacy of childhood and adult vaccines are also more likely to hold negative views about vaccinating their four-legged friends.

Public confidence in adult and child vaccines has declined during the pandemic, largely spurred by misperceptions and mistrust in the safety and efficacy of the COVID-19 vaccine. Now a new study led by a Boston University School of Public Health (BUSPH) researcher suggests that this hesitancy towards COVID vaccines extends to pet vaccinations, as well—and at worrying levels.

Published in the journal Vaccine, the study analyzed a nationally representative sample of adults in the United States and found that more than half of people who own dogs expressed some level of canine vaccine hesitancy—i.e. skepticism about vaccinating their pets against rabies and other diseases.

An estimated 45% of US households own a dog; according to the survey results, nearly 40% of dog owners believe that canine vaccines are unsafe, more than 20% believe these vaccines are ineffective, and 30% consider them to be medically unnecessary.

About 37% of dog owners also believe that canine vaccination could cause their dogs to develop autism, even though there is no scientific data that validates this risk for animals or humans.

The study is the first to formally quantify the prevalence, origins, and health policy consequences of concerns about canine vaccination. The survey was conducted between March 30 and April 10, 2023 among 2,200 dog owners who answered questions through the research sampling firm YouGov.

Notably, the findings show indication of a COVID vaccine "spillover" effect in the US—that people who hold negative attitudes toward human vaccines are more likely to hold negative views toward vaccinating their pets. These dog owners are also more likely to oppose policies that encourage widespread rabies vaccination, and less likely to make the effort to vaccinate their pets.

These attitudes are in contrast to most state-level polices in the US, where almost all states require domestic dogs to be vaccinated against rabies. The disease still poses a potential health threat, as it carries a near-100% fatality rate, and the canine rabies vaccine is much less accessible in developing countries than in the US and other high-income countries. More than 59,000 people die from canine-mediated rabies across the globe each year.

Thus, if fears towards pet vaccinations persist or increase, this skepticism could pose serious public health implications for both animals and humans, the researchers say.

"The vaccine spillover effects that we document in our research underscore the importance of restoring trust in human vaccine safety and efficacy," says study lead and corresponding author Dr. Matt Motta, assistant professor of health law, policy & management at BUSPH, who studies how anti-science beliefs and attitudes affect health and health policies. "If non-vaccination were to become more common, our pets, vets, and even our friends and family risk coming into contact with vaccine-preventable diseases."

The American Animal Hospital Association calls vaccinations "a cornerstone of canine preventive health care" and recommends that all dogs (barring specific medical reasons), receive a core set of vaccines for rabies, distemper, adenovirus, parvovirus, and parainfluenza, and advises that many dogs receive additional "non-core" inoculations for Lyme disease, Bordetella, and other diseases.

Working with animals that are not current on their rabies vaccine poses increased risks for veterinarians and all animal care attendants at a hospital, says study co-author Dr. Gabriella Motta, a veterinarian at Glenolden Veterinary Hospital in Glenolden, Pa. (and sister of Dr. Matt Motta). She says she encounters an unvaccinated animal or a vaccine-hesitant pet owner every day in her job.

"When a staff member is bitten by an animal, there is always concern for infection or trauma, but the seriousness of the situation escalates if the animal is unvaccinated or overdue for its rabies vaccine," Dr. Gabriella Motta says.

Per Pennsylvania Department of Agriculture guidelines, once a veterinary staff member is bitten by an undervaccinated or unvaccinated animal, the animal must undergo a period of observation and the staff member is encouraged to receive immediate medical attention. These situations place a mental health burden on the person bitten, as well as the rest of the veterinary staff, in an industry that already struggles with widespread burnout, understaffing, and job turnover, she says.

But she reiterates that the rabies vaccine is overwhelmingly safe and effective.

"With any drug, treatment, or vaccine, there is always a risk of adverse effects, but the risk with the rabies vaccine is quite low—especially when compared to the risk of rabies infection, which is almost 100 percent lethal," Dr. Gabriella Motta says. Pet owners who are concerned about the cost of pet vaccines may be able to seek low-cost options at local veterinary vaccination clinics, she adds.

The researchers don't believe canine vaccine hesitancy is widespread enough to pose a current threat to public health in the US, but that could change if vaccine misinformation and mistrust about animal and human vaccines are not quelled with sound, scientific data.

"It's important to remember that it once seemed unthinkable that MMR [Measles, Mumps, and Rubella] vaccine mandates in public schools might come under attack in state legislatures across the country," Dr. Matt Motta says. "And, yet, previous and ongoing research suggests that this is, indeed, the case."

The study's senior author is Dominik Stecula, assistant professor of political science in the College of Liberal Arts at Colorado State University.