Vaccine resistance in the United States isn’t limited to people. Alongside skepticism toward routine childhood and some adult vaccines, veterinarians are seeing the same hesitation spread to pets. What was once a routine part of preventive care has become a fraught interaction — and the implications extend well beyond animal health.

The American Animal Hospital Association and the Feline Veterinary Medical Association issue the nation’s standard vaccination guidelines. “Core” vaccines — rabies, distemper, and parvovirus for dogs; rabies and feline leukemia for cats — are recommended for nearly all animals. “Non-core” vaccines depend on a pet’s lifestyle and geography.

These recommendations evolve as data and experience accumulate. The vaccine for leptospirosis, a potentially fatal bacterial infection, was recently upgraded to “core” status after the disease proved to be more widespread than previously believed.

The reasoning is simple: Vaccinate your pet, protect it from a serious disease — and by extension, protect yourself from infections like rabies, leptospirosis and other “zoonotic” infections that can spread from pets to people.

No medical intervention is entirely without risk, but adverse reactions to pet vaccines are rare and usually mild. A significant study found side effects in about 0.2% of dogs — two per 1,000 vaccinations. The most common effects were brief soreness or swelling. Serious events, such as allergic reactions or injection-site cancers in cats, occur in 1 in 10,000 to 30,000 cases — far rarer than the deadly diseases vaccines prevent.

Even indoor pets aren’t immune to risk. Cats may encounter rodents; dogs can be exposed through backyard wildlife or owners’ shoes. Vaccination not only protects individual animals but also contributes to community-level protection across the broader pet population.

Until recently, few owners questioned their veterinarian’s recommendations. Now, some refuse core vaccines or accuse clinics of profiteering. The trend closely parallels human vaccine skepticism.

A 2023 national survey of 4,000 U.S. pet owners found that people who distrusted human vaccines were far more likely to doubt pet vaccines. Roughly 40% of skeptical owners believed dog vaccines were unsafe; 30% said they were unnecessary. A 2024 follow-up found that one-quarter of dog and cat owners could be classified as vaccine-hesitant.

Veterinarians are again treating diseases they rarely used to see — such as parvovirus in puppies and leptospirosis in unvaccinated dogs — and facing anger from clients who reject vaccination policies.

Researchers cite overlapping causes: spillover from human vaccine debates; erosion of trust in institutions; social-media misinformation; misperceived disease risk; exaggerated fear of side effects; and “natural immunity” myths that suggest pets get “too many shots.” Experts stress that the vaccine-hesitant are distinct from hardened anti-vaxxers: They’re undecided and often reachable through respectful dialogue.

This isn’t just a veterinary issue. A drop in vaccination could create new reservoirs for rabies or leptospirosis, putting pet owners and clinic staff at risk. Unvaccinated animals that bite humans can force costly, stressful rabies-prevention treatments.

There’s also a political dimension: Most states require rabies shots for pets, and if anti-vaccine sentiment expands, those laws could come under attack — with legal and health consequences for communities.

Veterinarians are adjusting how they communicate. The most effective strategies distinguish outright refusal from genuine ambivalence; build long-term relationships; present precise data on safety and benefit; and respond to fears with empathy rather than dismissal. Clinics are bundling vaccination with wellness visits and using reminders to make prevention easier.

For pet owners, the best approach is informed partnership: to ask which vaccines are core, how often boosters are needed, and what side effects to watch for. Rely on evidence-based sources, not anecdotes. And remember that vaccinating a pet safeguards the family, neighborhood and the wider community.

Veterinary epidemiologist Dr. Audrey Ruple of Virginia Tech warns that the United States lacks reliable national data on pet-vaccination rates — meaning the first clear signal of a decline may be outbreaks. Meanwhile, the same forces that have undermined human vaccination — politicization, misinformation, distrust — are infiltrating veterinary care.

Ultimately, pet-vaccine resistance reflects a deeper malaise: fraying trust in science and medicine. The logic of prevention remains unchanged. Vaccines spare suffering, extend lives, and protect pets and humans. Turning away from them invites the return of diseases that have long been kept at bay.

Our pets depend on us for everything — including protection from invisible threats. Keeping them vaccinated is among the simplest, most powerful acts of affection we can offer.

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ABOUT THE WRITER

Henry I. Miller, a physician and molecular biologist, is the Glenn Swogger Distinguished Fellow at the American Council on Science and Health. He wrote this for InsideSources.com.

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