Zulvac SBV (Inactivated Schmallenberg virus, strain BH80/11-4) is a vaccine used to protect cattle and sheep from Schmallenberg virus (SBV). It works by reducing viraemia, the presence of the virus in the blood, after infection. This helps to prevent the severe consequences of SBV infection, such as stillbirths and birth defects in offspring, which are caused by the virus's transmission through midges during pregnancy.