The researchers knew anecdotal evidence suggested many pet parents may be wary of canine vaccines, believing that it may result, at least in part, from negative sentiments toward the safety and efficacy of human vaccines.
“What shocked us, however, is just how prevalent these opinions are,” said Matt Motta, lead author and assistant professor at Boston University’s School of Public Health.
Although some vaccine hesitancy among dog owners isn’t new, veterinarians say people’s reluctance to vaccinate their pets has increased significantly since the pandemic, when many people expressed fear about coronavirus vaccines for humans.
For dog owners, vaccine hesitancy can stem from information people have read online about potential problems with vaccines, as well as personal experiences with negative reactions. The sheer number of shots required, concerns about overvaccination and the cost can also play a role.
Rena Carlson, president of the American Veterinary Medical Association (AVMA), said she understands some people may have concerns about vaccines based on past experiences, and veterinarians should work to address them.
“I think it’s important for us as a veterinary profession to educate people to help them understand the minimal risk versus the tremendous benefit,” she said. “The vaccines we use are indispensable tools to prevent life-threatening disease.”
Carlson and other veterinarians do recommend, however, that people speak with their veterinarians to tailor a vaccine plan based on the pet’s age, lifestyle, environment and medical history.
Many pet parents have posted on social media about their reluctance to vaccinate their dogs, which appears to stem from what they say are adverse and allergic reactions, worries from reading about poor outcomes and an anti-science bias.
Sarah Wooten, a veterinarian who works in veterinary education, recalled a case in which she recommended a pet parent vaccinate a young Rottweiler against common canine diseases, including parvovirus. Shortly after, the dog died of parvovirus, she said.
The parvovirus vaccine does not cause parvovirus, according to the AVMA. Still, “as a result of the death, the client mistrusted vaccines, which, if that happened to me, I would feel the same way,” Wooten wrote in an email.
For pet parents such as Regina Filippone, it’s more about avoiding overvaccination.
Filippone, a 59-year-old attorney from Torrance, Calif., met her “gorgeous beast”— a young Australian cattle dog mix — when the pooch hurled herself in front of Filippone’s car and started rolling around in the rain during a 2019 vacation in the Mexican state of Baja California.
After taking the muddy pup to nearby ranches to make sure she did not belong to them, Filippone cleaned her up, got her vaccinated — a requirement for crossing the border — and took her home to the Los Angeles suburbs.
It was three years before Filippone had to think about revaccinating her dog, now named Luna. By that time, she had been reading about overvaccination in pets and was concerned. She instead opted for titer testing, which measures the amount of antibodies in the blood.
Luna’s antibody levels “were as though she was just vaccinated,” Filippone said, so she decided to forgo the boosters — a decision that has barred Luna from facilities such as doggy day cares that require proof of rabies vaccination.
“I’m not an anti-vaxxer,” she said, “but I don’t understand why you would put more stuff in your dog when it’s not needed.”
The high prevalence of canine vaccine hesitancy could have public health consequences, the new study suggested.
Respondents who expressed more reluctance were more likely to oppose policies encouraging widespread rabies vaccination, for instance, and were less likely to be on board with vaccinating their own pets, Motta said.
Canine vaccinations protect both canines and humans, who can contract certain diseases from dogs, such as rabies, veterinarians say. Most states require rabies vaccinations for dogs, cats and even ferrets as the disease is almost always fatal for symptomatic animals — as well as humans.
Rabies is rare in the United States, but each year, up to 70 dogs and more than 250 cats are reported rabid — almost all of whom are unvaccinated — and there are 1 to 3 human cases, according to the Centers for Disease Control and Prevention.
The disease is responsible for about 59,000 human deaths worldwide each year, and in 99 percent of cases in which humans contracted the disease, domestic dogs infected with the virus had transmitted it to them, according to the World Health Organization.
“We’re not just protecting our pets. We’re also protecting ourselves,” said Lori Teller, clinical professor at the Texas A&M School of Veterinary Medicine and Biomedical Sciences.
Veterinarians agree canine vaccines save both animal and human lives, but say recommendations should be made on a case-by-case basis. Aside from the rabies shot, most veterinarians recommend that dogs get the other core vaccines, including distemper, parvovirus and canine hepatitis — some of which are “highly contagious and also frequently have a high morbidity and mortality rate associated with them,” Teller said.
There is more leeway with noncore vaccines such as the Bordetella vaccine, which protects dogs from kennel cough, or the shot against canine influenza or dog flu, an influenza A virus that has adapted to dogs. Based on circumstances, veterinarians may suggest skipping some vaccines, particularly for dogs that are older or have certain health conditions.
“We want to vaccinate appropriately,” Teller said. “We don’t want to overvaccinate, but we also don’t want to undervaccinate and leave a pet at risk.”
Some pet parents believe vaccines have a place, but do not want to overdo it.
For now, Filippone plans to monitor her dog’s antibody levels and, once they drop, she will probably revaccinate.
“But if it gets to the point where she’s an old dog,” Filippone said, “that might be a different decision.”