The following vaccination recommendations for equine herpesvirus-1 (EHV-1) were made by Julia Wilson, DVM, Dipl. ACVIM, associate professor of Veterinary Population Medicine at the University of Minnesota. There is some debate among researchers and veterinarians on which vaccine (modified live or killed) is best. Wilson reminds horse owners that no vaccine completely prevents disease, and vaccinated animals can still transmit the disease to others, so other disease prevention strategies (such as quarantine and good hygiene) should always be employed.

EHV vaccines currently on the U.S. market are: Calvenza EHV and CalvenzaEIV/EHV (killed virus, aka inactivated, from Boehringer Ingelheim); Pneumabort K (inactivated from Fort Dodge); Prodigy with Havlogen, Prestige, Prestige II, and Prestige V with Havlogen (all inactivated from Intervet); Fluvac Innovator EHV-4/1 and Fluvac Innovator Triple-E FT+EHV (inactivated from Ft. Dodge); and Rhinomune (modified live virus from Pfizer). No vaccines are labeled against the neurologic form of EHV-1.

Zylexis (Parapox Ovis virus vector) from Pfizer is an immunomodulator licensed to diminish clinical illness, particularly respiratory signs, from EHV-1 and -4 infections when administered prior to exposure and during disease incubation.
Following are some of the points to the debate:

1. In the case of EHV-1, data from Cornell University suggests that horses vaccinated with Rhinomune will have significantly lower nasal shedding of EHV-1 virus after being infected with EHV-1 than horses vaccinated with an inactivated vaccine. This mighty be important in limiting the spread of the virus