West Nile Virus (WNV) poses a significant threat to horses nationwide because it is carried throughout the country by infected birds during migration. Mosquitoes become infected after feeding on infected birds, and can then transmit the virus to horses. Vaccination remains the most effective way to help protect horses against WNV. Vetera WNV is for the vaccination of healthy horses and foals 4 months of age or older as an aid in the prevention of viremia and mortality, and an aid in the reduction of severity of clinical disease caused by WNV. This equine vaccine contains a killed virus and does not require reconstitution prior to administration. Vetera WNV provides at least 12 months of protection against WNV. In addition, this high quality vaccine may be administered to pregnant mares. Equine West Nile Virus vaccine For use in healthy horses and foals 4 months of age and older May be administered to pregnant mares Killed virus vaccine, no mixing required All vaccines are shipped Express 1-2 Days. A $29.95 flat rate fee is charged for all orders containing vaccines. Someone should be present to sign for and receive the vaccine order when it ships to you. For more shipping info click here. NOTE: This item cannot be shipped to Minnesota, Canada and P.O. Boxes. Use must be approved by your veterinarian.