Which Vaccines Do Horses Need?
Vaccines protect your horse from potentially serious diseases and prevent the spread of disease. Understanding which vaccines your horse needs can help you safeguard your horse's health.
Core Vaccines
Equine veterinarians recommend core vaccines for all horses. The vaccines protect horses from:
Eastern and Western Equine Encephalomyelitis (EEE/WEE). These diseases are spread through mosquito bites and can kill horses, although EEE is more likely to be fatal than WEE. Both diseases affect the central nervous system and may cause fever, listlessness, muscle twitching, sensitivity to touch, head pressing, trouble swallowing, loss of appetite, seizures and paralysis.
Vaccination Schedule. The American Association of Equine Practitioners (AAEP) recommends annual EEE/WEE vaccinations for horses 1 year and older. If an adult horse hasn't been vaccinated, it will receive one dose of the vaccine, followed by a second dose four to six weeks later. Thereafter, the horse should receive annual EEE/WEE vaccinations.
Rabies. Rabies is highly fatal and can kill horses in just a few days. Fortunately, the rabies vaccine prevents the disease from developing if your horse is bitten or comes in contact with a rabid animal. Symptoms of rabies include fatigue, aggression, agitation, anxiety, coordination difficulties, circling, head pressing, weakness, and fever.
Vaccination Schedule. The AAEP recommends vaccinating unvaccinated and previously vaccinated horses annually.
West Nile Virus. West Nile, a mosquito-borne virus, causes coordination issues, weakness, muscle twitching, lip smacking, sensitivity to touch and sound, and brain inflammation in severe cases.
Vaccination Schedule. Previously vaccinated adult horses receive annual West Nile vaccinations, while unvaccinated adult horses need an initial vaccine dose with another dose four to six weeks after the first dose.
Tetanus. Tetanus kills about 80% of affected animals, according to the Merck Veterinary Manual. Symptoms include stiffness, abnormal gait, trembling, lameness, colic, rigid muscles, and difficulty opening the mouth.
Vaccination Schedule. The AAEP recommend vaccinating previously vaccinated horses every year. After receiving the first dose of the tetanus vaccine, unvaccinated horses need an additional dose four to six weeks later.
The recommended vaccination schedule for foals varies depending on the mare's vaccination status.
Risk-Based Vaccines
Some horses also require risk-based vaccinations. These vaccines may be needed if a horse lives or travels to areas where certain diseases are common, spends time with horses from other areas of the country, or if your mare is pregnant. Your veterinarian can tell you which risk-based vaccines are recommended for your horse. Risk-based vaccines include:
- Anthrax. Horses develop this fatal disease by inhaling or swallowing anthrax spores found in soil. Symptoms include fever, breathing difficulty, colic, and tissue swelling.
- Botulism. Eating hay, grain, or grass contaminated by the botulinum toxin can cause botulism, a fatal disease that causes paralysis, weakness, and difficulty chewing and swallowing.
- Equine Herpesvirus. Equine herpesvirus is highly contagious. Depending on the type, it can cause fever, cough, nasal discharge, coordination issues, lack of appetite, inability to stand up, loss of bladder function, or miscarriage.
- Equine Influenza. This highly contagious disease can spread quickly at competitions, boarding facilities, and stables. Symptoms include cough, fever, nasal discharge, fatigue, and lack of appetite.
- Leptospirosis. Spread through the blood and urine of infected horses, leptospirosis causes fever, loss of appetite, blood in the urine, and miscarriage. The disease can also cause uveitis, a condition that inflames the inside of the eye and may lead to blindness.
- Potomac Horse Fever. Horses develop Potomac horse fever by swallowing caddisflies, mayflies, and other aquatic insects. High fever, diarrhea, swollen limbs, loss of appetite, fatigue, laminitis, and colic are symptoms of the illness.
- Rotavirus. This life-threatening illness affects young foals, causing watery diarrhea, dehydration, colic, lethargy, lack of appetite, and weight loss.
- Snake Bite. If you live in an area with venomous snakes, your veterinarian may recommend the snake bite vaccine.
- Equine Viral Arteritis. Equine viral arteritis is a viral illness that may cause flu-like symptoms, although some infected horses show no symptoms. This illness can also trigger miscarriages in pregnant mares.
The vaccination schedule varies for risk-based vaccines and may be different for foals and pregnant mares.
Not sure which vaccinations your horse really needs? Your veterinarian can recommend key vaccines and discuss the ideal vaccination timeline. Contact our office if you have vaccination questions or would like to schedule a visit.
Sources:
American Association of Equine Practitioners: Vaccinations for Adult Horses, 2023
https://aaep.org/wp-content/uploads/2024/02/Adult_Horse_Vaccine_Chart_2023_SUB.pdf
PetMD: Horse Vaccines: Which Vaccines Does My Horse Need?, 1/29/2025
https://www.petmd.com/horse/horse-vaccines
Merck Veterinary Manual: Vaccination Program for Horses, 9/2024
Penn State Extension: Vaccines for Your Horse
https://extension.psu.edu/vaccines-for-your-horse
Equus: The Core Vaccines: EEE/WEE, Rabies, West Nile Virus, Tetanus, 10/13/2023
https://equusmagazine.com/horse-care/core-vaccines-25417
Merck Animal Health: Foal Vaccinations
