Simbar Consultancy, Amsterdam, The Netherlands.
Abstracts of the papers presented at the International Conference of Indian Virological Society on “Emerging and Re-emerging viral Diseases of the Tropics and Subtropics” at Indian Agricultural Research Institute, New Delhi, India, December 11–14, 2007.
The historical background of foot and mouth disease (FMD) vaccine production is briefly described. Improvements achieved through the use of monolayer and suspension cultures are outlined. Elements that are crucial in the production of modern vaccines are discussed, such as inactivation of viral antigen, successive concentration and purification of the antigen and the final formulation of the vaccine. Storage of concentrated antigen at ultra-low temperatures creates greater flexibility for the producer and has also enabled national and international organisations to establish vaccine banks.
The very fast and safe (augmented) inactivation of FMD by a combination of formaldehyde and binary ethylene-imine will be discussed as well as the consequences for stability of the vaccine and its possible impact on “cold-chain” necessity. The purification of FMD viral antigens, including the removal of non-structural proteins (NSP), enables the immune responses of vaccinated animals to be distinguished from the responses of animals infected with live FMD virus. Consequently, the combined use of purified vaccine and tests for the detection of antibodies against NSP essentially provides a marker system to distinguish between vaccinated animals that subsequently become infected and those that have not. On the basis of the ‘performance’ of modern vaccines in outbreak situations and the possibility to screen vaccinated herds for carriers, the author discusses whether the OIE should reconsider the difference in the consequences for export between stamping-out and vaccination if used to control outbreaks.
