Very little scientific research has been done in the way of comparing the effectiveness of equine vaccines. However, several researchers have been hard at work over the past few years trying to determine if any particular U.S.-registered equine vaccines had advantages over others. It turns out that the serologic responses to–and protection given by–these vaccines varies significantly. Hugh G. G. Townsend, DVM, MSc, of the Department of Large Animal Clinical Sciences at the Western College of Veterinary Medicine in Saskatoon, Saskatchewan, presented results of the comparative study at the 2003 AAEP Convention.

The scientists looked at seven killed and one modified-live vaccine produced by the major U.S. vaccine manufacturers. Fifty naïve nine-month-old horses were used in the study. Blood samples were taken every four weeks to measure serologic response to influenza, tetanus, and equine herpesvirus, or EHV until they were challenged with equine influenza virus (EIV)