March 18, 2025 – As vaccination rates among people decline, a growing number of pet parents – often influenced by misinformation – are skipping vaccines for their pets, too, leaving animals vulnerable to serious illnesses.
About 6 in 10 veterinarians say that more pet owners are turning down rabies shots or other core vaccinations for pets after the COVID-19 pandemic, according to a survey. Public skepticism about human vaccines is spilling over to attitudes about vaccinating pets, veterinarians and experts said.
"People tend to generalize their feelings about vaccinations," said Lori Kogan, PhD, a psychologist and professor of clinical sciences at Colorado State University and chair of the Human-Animal Interaction Section of the American Psychological Association.
Other research from Texas A&M University found a close link between human and pet vaccine hesitancy. About 11% of dog owners and 12% of cat owners have concerns about the safety, efficacy, or importance of vaccines for their pets, the study showed. While most cats and dogs still get their shots, many don't – ranging from 6% of dogs missing rabies vaccines to 33% of cats unprotected against feline herpesvirus-1.
We asked veterinarians, psychologists, and immunologists to debunk the most common misconceptions they hear about pet vaccines.
Myth #1: Vaccines are more dangerous than the diseases they protect against.
Experts say: When vaccines for pets (and people) are highly effective, the number of new cases of the disease becomes extremely low. "It actually could be more common to hear of a side effect of the vaccine than to actually hear of illness from the disease itself," said George Moore, DVM, PhD, a professor emeritus at Purdue University College of Veterinary Medicine.
If you hear about a pet having a bad reaction to a shot, you might question vaccination, Kogan explained, noting that as humans, we tend to create connections – whether they're true or not.
Vaccine risks are low, while the benefit is "extremely high," said Moore.
For context: Adverse reactions happen in about 0.194% of dogs within three days of vaccination and 0.52% of cats within 30 days. Most are mild, like fatigue or soreness where the needle went in.
"Every pet is unique, but adverse events are uncommon," said S. Mark Tompkins, PhD, director of the Center for Vaccines and Immunology at the University of Georgia College of Veterinary Medicine.
By contrast, rabies is almost always lethal to pets (and people) once symptoms start. That's why the rabies shot is required by law in most states, under penalty of fines, or even euthanasia if an unvaccinated pet bites someone. Highly transmissible feline viruses can affect the respiratory or GI tract, causing coughing, sneezing, vomiting, and diarrhea – and potentially death. Parvovirus can be lethal to puppies. And leptospirosis, "a bacteria found in standing water that can cause acute kidney failure," can infect older dogs – and you, said Ambika Vaid, DVM, an integrative veterinarian with Chewy and an adviser to Badlands Ranch, a premium dog food company.
Myth #2: Vaccines contain dangerous ingredients.
Experts say: Despite concerns about thimerosal, a mercury-based preservative in certain human and animal vaccines, there's no evidence that the trace amounts in shots cause harm, the CDC says.
Scientific understanding of vaccine preservatives and adjuvants – ingredients that help stimulate the immune response – has been advancing for four decades, Moore said. "We have very, very safe products."
Animal vaccines, regulated by the U.S. Department of Agriculture, must go through a rigorous process to show they're safe and effective.
Want to know more? Every licensed vaccine (human or animal) has a package insert with information about what's inside. You can ask your vet to show it to you and explain, Tompkins said.
Myth #3: Vaccines can give your pet autism.
Experts say: Some 37% of dog owners believe canine vaccinations could cause autism in their pets, according to a 2023 survey of more than 2,000 U.S. adults. The notion may stem from the widely debunked theory linking vaccines to autism in humans, a concern that research doesn't support.
Regardless: "Pets don't get autism," Kogan said. "So that's not something to worry about."
Myth #4: Veterinarians give animals too many boosters.
Experts say: Research determines how often animals (or humans) get vaccines. Many boosters are given every three years because research suggests that's how long they last and sticking to that can help avoid gaps in immunity.
Same goes for puppies and kittens: New puppy owners are "shocked when I tell them that they need multiple vaccines or multiple visits" in the first 16 weeks, said Vaid.
Animal babies – like human babies – get antibodies from their mothers' milk. But when immunity from Mom wanes, the baby becomes vulnerable to disease. "If we miss that window where they are susceptible to infection," said Tompkins, "then at that point we have a dog with the distemper or a cat with a leukemia virus."
So, do vets give too many? No. But it is true that some pets, due to individual differences, can develop antibodies that last longer than three years.
For some vaccines, an antibody blood test can tell you whether your pet is still protected or they need a boost, said Laurie Larson, DVM, director of the Companion Animal Vaccines and Immuno Diagnostic Service Laboratory (CAVIDS Lab)/Titer Testing Service at the University of Wisconsin-Madison. These include canine distemper, parvovirus, or adenovirus, or feline panleukopenia.
For puppies, some breeders and reproductive veterinarians use titer testing or nomograph testing – an assessment of maternal immunity offered by Larson's lab – to create a tailored vaccination schedule, Larson said.
Can many shots at once increase the risk of side effects? That concern "is potentially valid only with our smallest pets or patients, more so on the dog side than the cat side," Moore said. If you have a small dog, you can ask to spread vaccines over two or more appointments.
Myth #5: If you need one vaccine, you need them all.
"One of the biggest issues is that people lump together all vaccines into one big chunk, one monolith, and it's not that simple," said Larson.
Each vaccine targets a specific disease, and whether your pet needs it may depend on their risk.
"If you have a dog that is going to grooming, doggy day cares, and dog parks very frequently, I would 100% recommend bordetella and the flu vaccine," said Vaid. "If you have an elderly dog that's sitting at home all day, not really doing much anymore, you probably don't need either of those vaccines."
If you live on the East Coast or in the Midwest, your vet might recommend a Lyme disease shot for your dog. And if you have a cat, your vet might recommend chlamydia and bordetella shots for a cat that spends time around other pets.
But "core" vaccines are recommended for every pet, regardless of lifestyle, because they protect against highly contagious, life-threatening diseases, including rabies, parvovirus, adenovirus, distemper, and leptospirosis in dogs, and rabies, feline leukemia, feline panleukopenia, feline herpesvirus-1, and feline calicivirus in cats. You might think your indoor cat or yard-restricted dog will never encounter the bacteria and viruses that cause vaccine-preventable disease – and that might be true – but you could also be overestimating your pet's safety, Kogan said. For example, other animals can leave feces in your yard that could infect your pet.
Don't be afraid to ask your vet to explain the risks and benefits of each vaccine, Moore said. Many will be happy to.
Myth #6: Your pet can't get kennel cough if they've had the bordetella vaccine.
Experts say: Bordetella vaccines boost immunity to Bordetella bronchiseptica, the most common cause of kennel cough. But other germs can also leave your pet hacking.
"Kennel cough is a big umbrella term for different viruses and bacterial infections that can cause that contagious cough," said Vaid. "Bordetella is just one bacterial component of that."
Still, the shot is worth it for many pooches. "I like to vaccinate dogs against it if I know they're going to be going out to dog parks, grooming facilities, and such, because it's an extra Band-Aid in case they get exposed to it, to protect them from that, that kennel cough disease essentially getting worse," said Vaid.
Myth #7: Shots are a big moneymaker for vets.
Experts say: Veterinary offices might get a lower price per shot if they order vaccines in larger quantities, but vaccine companies aren't sending them checks, Moore said.
Treating a sick animal costs more than vaccinating a healthy one. "Vaccines are a way to actually keep animals healthy, so if a clinician actually wanted to drive business, they wouldn't be vaccinating animals – they would just let them get sick," said Tompkins. "They want the best for your cat or your dog."
