Antigen and vaccine banks: technical requirements and the role of the european antigen bank in emergency foot and mouth disease vaccination

Abstract

Antigen and vaccine banks are stocks of immunogenic materials ready to be formulated into vaccines (bulk antigens) or ready to use (vaccines) in case of need by one or more of the parties of the bank. These stocks were primarily developed by foot and mouth disease [FMD] free European countries to control unexpected severe FMD episodes after the cessation of routine vaccination in the 1990s. For various reasons, including the lack of suitable antigens or of discriminatory tests to be used following emergency vaccination, such banks have so far not been developed to control other transboundary diseases, although over the last few years stocks of vaccines have been collected by the European Community to support control measures for bluetongue or classical swine fever. The FMD virus antigens in the banks are stored at ultra-low temperatures (usually -130 degrees C) to guarantee a shelf life of at least five years compared to a shelf-life of one to two years for vaccines stored at +4 degrees C. When concentrated, a 50 I volume of antigens can contain up to 15 million cattle doses as per the standard potency specifications in the OIE Manual of Diagnostic Tests and Vaccines for Terrestrial Animals. Selecting antigen/vaccine strains for storage in a bank and selecting the appropriate strain(s) to be used in the case of emergency vaccination is the responsibility of FMD disease experts. The paper discusses the role of serological testing for the detection of infected animals in a vaccinated population, which is necessary for the recognition of FMD status. Technical advantages and disadvantages of antigen and vaccine banks in general are also outlined in this article. Finally, the experience of the European Community in organising, renewing, and controlling a sizeable FMD antigen bank since 1993 is discussed, and the use of the European Union (EU) antigen bank for international actions outside the EU is presented.