Veterinarians agreed that vaccination is a critical component of an equine health maintenance program. A Table Topic on Vaccinations was part of the 2009 American Association of Equine Practitioners (AAEP) Convention in Las Vegas, Nev., in early December.

The attendees noted that veterinarians play a crucial role in client education, risk assessment, and herd evaluation to determine which vaccination program is best suited for an individual horse or herd. The vaccine technologies were briefly reviewed and included inactivated, modified live, chimera, recombinant, and DNA vaccine technologies.

A brief overview of immunization was presented by W. David Wilson, MS, BVMS, MRCVS, of the Department of Medicine and Epidemiology in the School of Veterinary Medicine at the University of California, Davis. Factors that affect vaccine decisions were discussed and included the onset of immunity following vaccination, the duration of immunity, safety, convenience, cost of the product, and challenges with our ability to assess equine immunity.

The AAEP has identified tetanus, Eastern and Western equine encephalomyelitis (EEE, WEE), West Nile virus (WNV), and rabies as core vaccinations for every horse. As a general rule, all adult horses need to be boosted at least annually. Horses living in the southeast need to be boostered more frequently for the encephalomyelitis viruses. The need to vaccinate against EEE twice annually or more frequently was discussed