This product has been shown effective for the vaccination of healthy horses 6 months of age or older against Eastern and Western encephalomyelitis (EEE and WEE) viruses, equine influenza virus (EIV), equine herpesvirus type 1 (EHV-1), equine herpesvirus type 4 (EHV-4), and tetanus. Duration of immunity has been shown at 6 months for EIV. Duration of immunity for Eastern and Western encephalomyelitis viruses, EHV-1, EHV-4 and tetanus has not been established. For more information regarding safety and efficacy data, go to productdata.aphis.usda.gov. This product has been shown to be effective against virus shedding of EIV and EHV-1.