Vaccination Time: Spring Check-Ups for Horses

By Leslie Barlow, EDCC Communications Manager 

When the clock springs forward to signal a change in the seasons, your horse’s vaccinations records need an update to help protect against potentially fatal equine diseases. 

For adult horses, “spring shots” should be performed mid-March to mid-April to make sure immunity is boosted before likely exposure to insect and animal vectors. 

A standard vaccination program for all horses does not exist. Each individual situation requires evaluation based on the following criteria: risk of infection, consequences of the disease, anticipated effectiveness, potential for severe adverse reactions to vaccines, and cost of immunization versus potential cost of disease. The timing of the vaccination is critical to ensure the horse’s immune system peaks during the highest risk period for the disease exposure. 

According to the American Association of Equine Practitioners (AAEP) vaccination guidelines, the five core vaccinations that all horses need include: West Nile Virus, Eastern and Western Equine Encephalomyelitis (EEE and WEE), tetanus and rabies. All horses are exposed to these potentially fatal diseases and need to be vaccinated annually. In some cases, multiple vaccinations during the year may be advisable depending on the environment and horse activity. 

Core vaccinations protect against diseases that are endemic to a region, are virulent or highly contagious, pose a risk of severe disease, pose a public health risk, and/or are required by law. These vaccines are recommended for all equids because they demonstrate efficacy and safety, with a high level of patient benefit and low level of risk. 

West Nile Virus, EEE, & WEE are three mosquito-borne viruses that can cause severe and often deadly neurologic diseases. Tetanus is caused by the neurotoxin of bacteria Clostridium tetani, which often enters the body through puncture wounds or lacerations (like people).  Tetanus can be deadly or at least require long-term intensive care in a hospital setting. The Tetanus vaccine is highly effective and because it is commonly used, it’s relatively uncommon to see an equine case of tetanus. Rabies is rare, but there is a risk of exposure from wildlife.  Rabies is essentially fatal. Rabies legally must be administered by a veterinarian. 

 Although no vaccine prevents all diseases, all these diseases have highly effective vaccines which can prevent death or decreases the number of sick horses. EEE, WEE, West Nile, and Tetanus are often combined in one vaccine to make a “four-way”, aka a “3-way and West Nile”.  Having your veterinarian administer the vaccine helps guarantee the efficacy of the vaccine.  

“All horses, no matter where they live or how they are managed are susceptible to these core diseases, which can cause extreme illness and even death,” said Dr. Katie Flynn, Equine Health and Biosecurity Veterinarian for the United States Equestrian Federation. 

Horses who travel or comingle with new horses at horse shows or on the farm are often at higher risk to be infected with additional viruses or bacteria and will benefit from vaccination. Veterinarians recommending risk-based vaccinations for horses in these situations will often suggest additional protection against equine influenza and equine herpesvirus (EHV). The AAEP list of risk-based vaccines also includes Anthrax, Botulism, Equine Viral Arteritis (EVA), Leptospirosis, Potomac Horse Fever, Rotavirus, Snake Bites, Strangles, and Venezuelan Equine Encephalitis (VEE). Owners and trainers should ask their veterinarian about whether their horses need risk-based vaccines in addition to the core vaccines. 

“Vaccinations don’t guarantee 100% protection, so pairing them with a good biosecurity program is crucial,” said Dr. Flynn. 

The AAEP vaccination guidelines include foal and adult horse vaccination charts for core and risk-based vaccines with guidance on when foals should receive their first round of shots and boosters as well as when adult horses need booster shots.

Veterinarians can guide you on the best timing of the vaccines that are right for your horse and situation. 

The EDCC is an industry-driven information center which works to protect horses and the horse industry from the threat of infectious diseases in North America. The center is designed to seek and report real-time information about diseases similar to how the Centers for Disease Control and Prevention Center (CDC) alerts the human population about diseases in people. The EDCC is based in Lexington, Ky. At the American Association of Equine Practitioners headquarters, with a website and call center hosted by US Equestrian. The EDCC is funded entirely through the generosity of organizations, industry stakeholders, and horse owners. To learn more visit www.equinediseasecc.org.