Vaccine Hesitancy

Vaccine Hesitancy

 

Recently, human medicine has faced a growing number of people rejecting mainstream science on vaccines and choosing not to vaccinate.  This attitude is creeping into veterinary medicine.  In 2016 over 84% of pet owners vaccinated their pets when they were young; in 2019, that number dropped to 66% (Mattson, 2020).  Pritchard (2025) cites a study where 53% of respondents in the U.S.A. felt vaccines for dogs were unsafe or unnecessary.

 

At the core of the issue is the development of vaccines using mRNA (messenger RNA, which uses DNA as its template) rather than using organisms that activate an immune response.  mRNA vaccines have the advantage of rapid development and processing (Le et al., 2022), but this speedy process is highly controversial, particularly given the history of meticulous development and approval by the FDA (Lipsky, M.S. & Sharp, L.K., 2001).  In the field of veterinary medicine, mRNA research is focused on zoonotic diseases (those that can be transferred to people) and not readily available for other veterinary diseases (Le et al., 2022).  Fox Run Animal Hospital does not use any mRNA vaccines.

 

Websites that identify as “natural” or “holistic” add to the fray when they warn people of the dangers of over-vaccination (Mattson, 2020).  However, these self-proclaimed experts do not define “over-vaccination”.  Veterinary professionals all agree that vaccines should be administered appropriately, so this is a non-issue.

 

In stark contrast, all professional veterinary groups worldwide, including the American Veterinary Medical Association (AVMA), Federation of Veterinarians of Europe (FVE), and Canadian Veterinary Medical Association (CVMA) (AVMA, 2025), as well as the World Small Animal Veterinary Association (Squires et al., 2024) and the American Animal Hospital Association (Ellis et al., 2022), stress the importance of vaccinating your pet.  There are many reasons they advocate for vaccination, but a few of the most important are:

1. The World Health Organization reports that tens of thousands worldwide die of rabies every year (Squires et al., 2025). Most of these deaths are caused by bites from rabid dogs.  This is rare in the U.S. because rabies vaccines are mandated in most states, including Michigan (Michigan Legislature, 2026).
2. When most of the population is vaccinated, herd immunity occurs. This means that those pets that cannot withstand vaccination (pregnant, immunocompromised, or pets that previously experienced an adverse reaction) are relatively safe from the disease.
3. In many parts of the world, Leptospirosis (a zoonotic disease that can spread from an animal to a human), Lyme and feline leukemia are endemic (Ellis et al., 2022, Squires et al., 2024).
4. The DAPP vaccine (also known as DHPP or DA2PP), protects against highly contagious and potentially lethal viruses: distemper, hepatitis, upper respiratory, and parvovirus (MetLife, 2024).

 

It is common for a pet to experience mild and short-lived side effects from vaccines such as tenderness and swelling at the vaccination site, tiredness, mild fever and/or decreased appetite.  These symptoms usually go away within 24 hours (AVMA, 2025).  Some animals can experience an allergic reaction to a vaccine, but this generally occurs within minutes and can be treated immediately by the veterinarian (Hartmann et al., 2023).  Hypersensitivity reactions can happen 1-3 days post vaccination when multiple injections are given at the same time, but this is uncommon and rarely severe (Moore et al., 2023).

 

Feline injection-site sarcoma (tumor) is an area that has received a lot of attention from researchers.  Ultimately, the researchers concluded that there is no evidence that a vaccine causes this (Hartmann et al., 2023; Lappin, 2015).  Rather, some cats are genetically pre-disposed toward an inflammatory response to anything injected that, over time, may develop into a tumor.  In an abundance of caution however, vaccines were refined.

 

Stone et al. (2020), categories vaccines as inactivated, attenuated live, and recumbinant.

• Inactivated vaccines cannot replicate the virus because they are not “live”. Thus, they often contain excipient proteins (known as adjuvants) to promote an immune response.  Inactivated vaccines produce weaker immune responses and require more frequent boosters.
• Attenuated live replicates the virus to stimulate an immune reaction; no adjuvant is required. The immune response is faster and the vaccine “sheds” to protect other animals.  However, there is also a risk of developing a vaccine organism-induced disease.
• Recumbinant vaccines are vectored by incorporating the pathogen (the specific portion of the germ that incites the immune response) into a canarypox genome; no adjuvant is required. Recumbinant vaccines offer a faster immune response with better effectiveness than inactivated and reduce the risk of injection-site sarcomas in cats.  The Department of Health and Human Services (2022) recognizes recombinant vaccines as having a very strong immune response that can be safely used on patients with long-term health issues.

 

Overall, the AVMA, FVE, and CVMA (2025) state:

“Vaccines have been used for centuries to effectively decrease morbidity and mortality associated with many infectious diseases, and in the vast majority of cases, the benefits of scientifically sound vaccination programs outweigh any potential risks.”

 

At Fox Run Animal Hospital YOUR PETS’ HEALTH IS OUR TOP PRIORITY.  We provide our clients with the best medical information using the latest scientific research so they can make informed decisions about the health and wellbeing of their pet.

 

References:

American Veterinary Medical Association (AVMA). (2025). Vaccinating Your Pet. https://www.avma.org/resources-tools/pet-owners/petcare/vaccinations, 3/1/2026.

Ellis, J., Marziani, E., Aziz, C., Brown, C.M., Cohn, L.A., Lea, C., Moore, G.E., Taneja, N. (2022). 2022 AAHA Canine Vaccination Guidelines. Journal of the American Animal Hospital Association, 58:213-230. DOI:10.5326/JAAHA-MS-Canine-Vaccination-Guidelines.

Hartmann, K., Egberink, H., Möstl, K., Addie, D. D., Belák, S., Boucraut-Baralon, C., Frymus, T., Lloret, A., Hofmann-Lehmann, R., Marsilio, F., Pennisi, M. G., Tasker, S., Thiry, E., Truyen, U., & Hosie, M. J. (2023). Feline Injection-Site Sarcoma and Other Adverse Reactions to Vaccination in Cats. Viruses, 15(8), 1708. https://doi.org/10.3390/v15081708.

Lappin, M. (2015). Infectious Diseases: Small Animal Seminar Series. Michigan Veterinary Medical Association. October 15, 2014.

Le, T., Sun, C., Chang, J., Zhang, G., & Yin, X. (2022). mRNA Vaccine Development for Emerging Animal and Zoonotic Diseases. Viruses, 14(2), 401. https://doi.org/10.3390/v14020401

Lipsky, M.S., Sharp, L.K. (2001). From Idea to Market: The Drug Approval Process. The Journal of the American Board of Family Practice, 14(5), 362-367. https://www.jabfm.org/content/14/5/362

Mattson, K. (2020). Vaccine Hesitancy: Veterinary Professionals Face Challenges Surrounding Vaccinations. JAVMAnews, March 1, 2020. https://www.avma.org/javma-news/2020-03-01/vaccine-hesitancy, 3/2/2026.

MetLife Pet Insurance. (2024). DAPP Vaccine for Dogs: What It Is & Its Cost. https://www.metlifepetinsurance.com/blog/pet-health/dapp-vaccine/, 3/9/26.

Moore, G.E., Morrison, J., Saito, E.K., Spofford, N., Yang, M. (2023). Breed, Smaller Weight, and Multiple Injections are Associated with Increased Adverse Event Reports within Three Days Following Canine Vaccine Administration. Journal of the American Veterinary Medical Association, 261(11), 1653-1659. https://doi.org/10.2460/javma.23.03.0181, 3/2/2026.

Michigan State Legislature. (2026). Dog Law of 1919, MCL – Section 287.266. https://www.legislature.mi.gov/Laws/MCL?objectName=MCL-287-266, 3/1/2026.

Pritchard, J. (2025). Understanding and Navigating Vaccine Hesitancy Among Veterinary Clients. Today’s Veterinary Practice. https://todaysveterinarypractice.com/public-health/vaccine-hesitancy-among-veterinary-clients/, 3/1/2026.

Squires, R.A., Crawford, I.C., Marcondes, M., Whitley, N. (2024). 2024 Guidelines for the Vaccination of Dogs and Cats: Compiled by the Vaccination Guidelines Group (VGG) of the World Small Animal Veterinary Association (WSAVA). Journal of Small Animal Practice. https://wsava.org/wp-content/uploads/2024/04/WSAVA-Vaccination-guidelines-2024.pdf, 2/28/2026.

Stone, A.E.S., Brummet, G.O., Carozza, E.M., Kass, P.H., Petersen, E.P., Sykes, J., Westman, M.E., Stud, E. (2020). 2020 AAHA/AAFP Feline Vaccination Guidelines. Journal of Feline Medicine and Surgery, 22:9, 813-830.  DOI:10.1177/1098612X20941784.

U.S. Department of Health and Human Services. (2022). Vaccine Basics: Vaccine Types. Immunization for You and Your Loved Ones. https://www.hhs.gov/immunization/basics/types/index.html, 3/10/26.