Over half of US dog owners expressed concerns about vaccinating their pets, according to a new study. Researchers from Boston University questioned over 2,200 people and 53% questioned the safety, efficacy, and necessity of vaccinating their dogs. Also, 37% feared vaccines could trigger autism, despite there being literally zero risk for that.

Vaccines help teach dog’s immune system how to recognize and fight off certain disease-causing agents. They work by stimulating the immune system’s production of antibodies that identify and destroy these agents. Widespread use of vaccinations within the last century has prevented death and disease in millions of animals.

We are used to hearing about vaccine skepticism in people, especially after Covid-19. But it seems this rhetoric has now been passed on to dogs, despite the lack of scientific evidence to support such views — in both humans and canines.

In their new study, the researchers looked at “canine vaccine hesitancy,” or CVH, a phenomenon they found to be expanding fast across the United States.

“CVH is problematic not only because it may inspire vaccine refusal — which may, in turn, facilitate infectious disease spread in both canine and human populations — but because it may contribute to veterinary care provider mental/physical health risks,” the researchers wrote in their study, published recently in the journal Vaccine.

Dogs and vaccines

There are about 65 million households in the US that have a pet dog, according to the National Pet Ownership Survey. Most states legally require dogs to be vaccinated against rabies within their first year of life. This protects the animals and their owners. Other common diseases include parvovirus and distemper, all of which can be fatal.

The study involved a nationally representative group of 2,200 adults, of which 42% (924) had dogs. The researchers found canine vaccine hesitancy is expanding fast in the US, a problem that goes beyond dogs. Those not vaccinating their pets are also more likely to embrace misinformation and falsehoods linked to human vaccines, the study showed.

Responses by the study participants showed that 56% rejected mandatory vaccination against rabies, a fatal disease. Also, 37% of dog owners said believed that vaccines could cause their pets to develop cognitive problems, such as autism. Studies have shown there’s no link between vaccines and autism. Plus, canine autism isn’t even a thing.

The lead author of the study, Matthew Motta, told Ars Technica he was very surprised by the results.

“We were shocked to uncover just how prevalent canine vaccine hesitancy is and to observe just how powerful CVH can be in explaining why some people might choose to not vaccinate their pets,” Motta said in an interview.

Motta said he and his team had seen for years anecdotal evidence that Americans were becoming hesitant to vaccinate their pets. However, no study so far has attempted to quantify this phenomenon. If these attitudes persist and result in fewer pets being vaccinated, it could represent a major public health problem, they argued.