Horse Vaccines: What You Need To Know

Jennifer Rice, DVM, CVSMT
By Jennifer Rice, DVM, CVSMT on Apr. 26, 2022
Horse vaccine

Vaccines are an essential part of maintaining a healthy, happy horse. Vaccines are meant to create immunity against specific diseases. By vaccinating your horse for these diseases, you reduce the risk of the horse getting sick, or if they happen to get sick, it will lessen the severity of the disease and likely will be less contagious. Vaccines are created with a weaker version of the specific disease and, when given to the horse, cause the body to form antibodies to help protect the horse from the disease.

Which Vaccines Are Available for My Horse?

Horse vaccines are categorized by the American Association of Equine Practitioners (AAEP) as either core vaccines or risk-based vaccines. Core vaccines are considered essential vaccines that every horse, no matter their lifestyle or risk, should be vaccinated against because they pose a risk to every horse and are potentially fatal. Risk-based vaccines are vaccines that should be considered and discussed with your veterinarian based on your horse's unique risk, geological location, and lifestyle.  

Core Vaccines:

Risk-based Vaccines:

Horse Vaccination Schedule 

The following charts contain the recommended immunization schedules for adult horses after initial vaccination.

Core Vaccines

Eastern/Western Equine Encephalitis

  • Frequency: Annual/spring, prior to onset of vector season

  • Consider 6-month revaccination interval for high-risk situations and regions of increased occurrence


  • Frequency: Annual


  • Frequency: Annual

  • Booster at time of penetrating injury or prior to surgery if vaccine was given over 6 months previously

West Nile Virus

  • Frequency: Annual/spring, prior to onset of mosquito season

Risk-based Vaccines 


  • Frequency: Annual


  • Frequency: Annual

Equine Herpesvirus (EHV)

  • Frequency: Annual

Equine Viral Arteritis (EVA)

  • Frequency: Annual

  • Prior to initial vaccination: stallions and any horses potentially intended for export should undergo serologic testing to confirm negative for antibodies to EVA

Equine Influenza 

  • Frequency: Annual

    • Semi-annual for horses that will be in high risk for more than 6 months of the year 

  • Horses in high-risk lifestyles include hoses competing more than 6 months of the year or in boarding/training facilities. These horses should be vaccinated every 6 months


  • Frequency: Annual

Potomac Horse Fever (PHF)

  • Frequency: Semi-annual to annual

  • Revaccination interval of every 3-4 months may be recommended for horses in endemic areas with high risk


  • Given to broodmares ONLY: 3 dose series during pregnancy

Snake Bite

  • Frequency: Semi-annual

  • Recommend for geologic areas of high risk, with venomous snakes


  • Frequency: Semi-annual to annual due to lifestyle risk

  • Horses in high-risk lifestyles include hoses competing more than 6 months of the year or in boarding/training facilities. These horses should be vaccinated every 6 months

Horse Vaccination FAQs

Is there a better time of year to give vaccines?

Generally, vaccines are recommended to be given in the spring before riding season begins in order to give the horse the most protection. Some vaccines may require a booster in the fall, depending on the horse's lifestyle and risk level.  

Do show horses need additional vaccines?

Yes, horses that are being shown need to be given additional vaccines because they are at risk for other diseases, such as influenza and strangles, due to traveling and being exposed to new horses and facilities. 



 AAEP. Vaccination guidelines. 2020.

Featured Image: Neville


Jennifer Rice, DVM, CVSMT


Jennifer Rice, DVM, CVSMT


Dr. Jennifer Rice is a 2017 graduate from Purdue College of Veterinary Medicine where she specialized in Equine medicine. Since graduating...

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