After making a significant dent into vaccination numbers among the human population, the anti-vaccination movement now has a four-legged target.
The Guardian reports that owners of cats and dogs are being advised against vaccinating their pets for fear of causing cancer, autoimmune hemolytic anemia and even autism.
Yes, you read right - one letter to magazine Psychology Today asked if vaccinating a dog could lead to canine autism.
Psychology expert Professor Stanley Coren was quick to pour cold water on the theory, saying vaccines do not cause autism and the benefits of immunity far outweigh any risks.
"This seems to me to be a pretty severe risk to take with your pet dog on the basis of a scientifically disproved association between vaccination and autism," he said.
The figurehead of the US pet anti-vaccination movement, Dr John Robb, was placed on probation by the Connecticut State Board of Veterinary Medicine for reducing the dosage of rabies vaccines he was giving to some dogs.
Dr Robb has long been vocal about his stance that smaller dogs should not receive the vaccination dosage larger dogs receive, but other members of the veterinary community disagree.
"Immunologists say vaccines are not dose-dependent, that you need enough antigens to stimulate the immune system", California vet Dr Lisa Boyer told the Guardian.
"It's not a weight-versus-dose question. My seven-year-old and I get the same vaccine."
In New Zealand, the SPCA recommends dogs, cats and rabbits are all vaccinated against a range of preventable diseases.