Volume 7: Medicines and Cosmetics
3. Initial response on veterinary medicines
Use of animal materials prior to the emergence of BSE

3.2 Prior to the emergence of BSE, the use of substances of animal origin in the manufacture of veterinary vaccines had been the subject of general guidance contained in a Medicines Act Leaflet (MAL 67), published in June 1983. ¹ We were told this was the most recent of a series of guidance notes influenced by an earlier incident in which scrapie had been disseminated via a louping-ill vaccine, in which brain and spleen tissue from scrapie-infected sheep had been directly incorporated. ²

3.3 In the section headed 'a guide to current practice' MAL 67 said:

Restrictions are placed upon the use of substances of animal origin in order to minimise the risk associated with pathogens which may be present in these materials. Unless there is a risk from a heat-resistant pathogen such as the scrapie agent, no restrictions are placed on substances sterilised by autoclaving provided that the complete mass is held at a minimum of 115°C for at least 15 minutes. Restrictions on the use of substances that cannot be sterilised by autoclaving vary according to the target species, the species of origin, the country of origin and whether the substance undergoes at any stage treatment which will inactivate contaminating agents. ³

In practice this meant that cattle tissues were used instead of sheep material. ⁴