Female veterinarian gives horse a vaccine.

Understanding the Risks to Equine Health

Equine | March 2025

Written by:

Bio not available.

How veterinarians can determine the right vaccination program for individual horses depends on several key factors.

Vaccinations for horses fall into two categories – core and risk-based.

Core vaccinations protect against diseases that are endemic to a region, are virulent/highly contagious, pose a risk of severe disease, those having potential public health significance, and/or are required by law, the American Association of Equine Practitioners (AAEP) states. There are five core vaccines that all horses should receive: Eastern EEE and Western Equine Encephalomyelitis WEE, West Nile Virus, tetanus, and rabies.

Risk-based vaccines, meanwhile, are selected for use based on risk assessment performed by, or in consultation with, a licensed veterinarian, the AAEP noted. Use of these vaccines may vary between individuals, populations, and/or geographic regions. The vaccines include anthrax, botulism, equine herpes virus, leptospirosis, equine influenza, Potomac horse fever, snake bites and strangles.

Black and White image of mare and foal.

A risk-benefit analysis looks at known risk factors and the benefits of vaccination to determine if giving the vaccination is the best option for that horse. Many factors are considered during this analysis, and the veterinarian plays a critical by performing the analysis. According to Penn State, common questions during a risk-benefit analysis include:

  • Is the horse located in an area where a particular disease is common?

  • Does the farm have new horses coming on the farm regularly that may be carrying diseases?

  • Do some of the horses on the farm travel regularly?

  • Will the horse be traveling to other locations/states? Will the horse be in an area where a disease is prominent?

  • Is the horse competing at shows?

  • Will the horse be interacting with other horses? (Particularly with those from different farms)

  • How old is the horse? Is the under 2? Is the horse geriatric (over 20)? (Note: If the horse is a foal or weanling, there are specific guidelines for both core and risk-based vaccines that can be found on the AAEP website.)

  • Is the horse in good health? Is it immunocompromised?

  • Will this horse be used for breeding or is it currently in foal (pregnant)?

Learn more about AAEP’s vaccination guidelines.

 

Photo credits:

istockphoto.com/lemono

istockphoto.com/Somogyvari

>