Allergy/Immunology

The AAEP designates tetanus, eastern and western equine encephalomyelitis (EEE/WEE), West Nile virus, and rabies as core vaccines. Booster timing depends on exposure risk, geography, and individual health status.

Annual boosters are common, though semiannual revaccination may be considered for high‑risk or traveling horses. Veterinarians tailor intervals to disease prevalence, show schedules, and farm management.

Core vaccines protect against widespread, often fatal diseases, while risk‑based options—such as EHV/EIV, strangles, or botulism—are administered according to region, travel, and management factors.

Most reactions are mild and transient, including soreness or low‑grade fever. Severe events are rare; affected horses should be monitored and the reaction reported to the manufacturer and veterinarian.

Immunosuppressive therapies can blunt antibody production and cellular responses. Vaccination timing and product selection should be planned with veterinary oversight when horses receive corticosteroids or other immunomodulators.

Advances in adjuvant technology, mucosal delivery, and titer‑based revaccination are enabling more precise protection with fewer adverse effects. Research is also clarifying duration of immunity for common antigens.

Communicate local risk, efficacy data, and safety profiles clearly, and pair vaccine visits with wellness checks. Written plans and reminders increase adherence and strengthen herd immunity.