Vaccines

Until 1991, the whole of continental Europe (except Denmark) routinely vaccinated against FMDV. Britain and Eire did not do this and, as a consequence, British / Irish / Danish national herds/flocks did not contain any anti-FMDV antibodies. Mainland european animals did, however, contain such antibodies. At that time, one could not differentiate between animals being sero-positive due to vaccination, or, due to having previously been infected with virus. Having no sero-positive animals, Britain / Eire / Denmark were able to categorically state that none of their animals had been infected, which conferred certain trading advantages over other European nations.

To ‘harmonize’ trading positions throughout the EU, one could either introduce routine vaccination throughout all members of the EU, or, cease routine vaccination throughout the EU. Based upon cost-benefit analyses, the latter strategy was adopted. Future disease control would be mass-slaughter combined with ‘ring-vaccination’ in extremis. Maintaining completely naive national herds/flocks naturally ran the risk, however, of large-scale outbreaks should FMDV get into the UK.

Why, then, stop routine vaccination? Naturally, there is the direct cost of vaccine administration, surveillance of the immune status of herds, the problem of vaccinating animals dispersed over the countryside and the restrictions placed upon trade. Routine vaccination has, however, other consequences. Unlike poliovirus, it has not been possible – to date – to produce live, attenuated, vaccine strains of FMDV – like the Sabin vaccine strains of poliovirus. The same strategy that was adopted by Jonas Salk for the killed poliovirus vaccine has been adopted for the production of FMDV vaccines: large-scale growth of pathogenic virus followed by chemical inactivation. This, naturally, has attendant risks: in the case of poliovirus for example, incomplete inactivation of the virus preparation lead to the ‘Cutter Incident’ (1955) in which 94 cases of poliomyelitis occured amongst Cutter vaccinees. 126 cases were reported amongst family contacts and 40 cases amongst community contacts of vaccines. These days, however, inactivation and testing is a very much more well-understood and controlled process. The second major source of risk, however, is still present – the escape of pathogenic virus from research / vaccine production facilities.

The purpose of our research is to bring to bear modern molecular techniques to (i) produce a new generation of FMDV vaccines – live, attenuated, genetically-stable, vaccine strains and/or (ii) to use an improved understanding of how the virus grows in cells to modify both the genomes of cells and viruses to greatly enhance biosecurity during the production process.