Glycoprotein gE is absent in virus particles of Rispoval IBR-Marker Live. Therefore the vaccine virus, and the antibodies against it, can be clearly differentiated from field strains, or antibodies against the latter by serological methods, unless the cattle were previously vaccinated with a conventional vaccine or infected with field virus.
The vaccine induces immunity in cattle against clinical respiratory symptoms caused by the Infectious Bovine Rhinotracheitis (IBR) virus. After a single dose vaccination, a significant reduction of virus shedding duration has been demonstrated upon challenge. After two doses of vaccine, the intensity and duration of clinical symptoms as well as the titre and duration of virus shedding are significantly reduced following infection. As with other vaccines, vaccination may not completely prevent but does reduce the risk of infection.
The veterinary medicinal product induces antibodies in vaccinated cattle, which are detectable in serum neutralisation tests and in conventional ELISA tests. With specific test kits these antibodies can be differentiated - due to the lack of antibodies against gE - from those of field virus infected animals or animals vaccinated with conventional vaccines.
Vaccination of all cattle in a herd, both infected and uninfected, is recommended. Following use of Rispoval IBR-Marker Live the risk of infection, titre and duration of virus shedding are all reduced. The duration of a programme to achieve the status of a BoHV-1 free herd is dependent on the initial level of BoHV-1 infection in the herd and the culling of remaining BoHV-1 positive animals.