ABSTRACT
The historical background of FMD vaccine production, the Valléé-Schmidt-Waldmann concept, the production of antigen in bovine tongue epithelium (Frenkel culture) and improvements achieved through the use of monolayer and suspension cultures of cell lines are described. Key elements of modern vaccine production are discussed such as the production environment, bio-safety concepts, rules for good manufacturing practice, requirements for culture medium, cells, virus strains, inactivation of viral antigen, and successive concentration and purification of the antigen. Storage of the concentrated antigen at ultra-low temperatures creates greater flexibility for the producer. In addition, it allows national and international organisations, the opportunity to establish vaccine banks for emergency vaccination. For the latter purpose it is even more important that antigens are purified. The purification of FMD viral antigens – including the removal of nonstructural proteins (NSP) – provides a system that can distinguish between the immune responses of vaccinated animals from those of animals infected with live FMD virus. Consequently, the combined use of purified vaccine and anti-NSP tests essentially provides a “marker” system.
Possibilities for the world-wide control and eradication of FMD by vaccination, including the institution of regional vaccine banks, are discussed. Modern (qualified) FMD vaccines perform very well both for regular vaccination programs and for the control of outbreaks, and over the past 15 years there are no well-documented cases where cattle vaccinated with an approved vaccine have caused new outbreaks. Therefore, whether there continues to be justification for sanctions on trade, when controlling single (limited) outbreaks by (ring-) vaccination.
