Vaccination program in the response to the 2007 equine influenza outbreak in Australia.

At the time of the initial notification of the occurrence of equine influenza (EI) in Australia in August 2007, vaccination was restricted to horses for which it was an import requirement and only with the approval of the state or territory Chief Veterinary Officer. This paper describes the complexities involved in the selection of a vaccine and its distribution. A combination of ring, predictive and blanket vaccination was implemented during the response. The specific vaccination programs, including its use in buffer zones and for movement of horses, the performance of the vaccine, any adverse reactions and the effect on exposure of vaccinated horses to circulating virus, are also described. Vaccination is considered to have made a valuable contribution to the containment and subsequent eradication of EI from Australia and to risk management in the resumption of horse activities in affected areas from December 2007. Movement restrictions and other biosecurity measures were critically important in controlling the spread of EI and contributing to its eventual eradication, and vaccination was an aid to these measures.