Regulatory practices and problems with vaccine stability studies and the establishment of shelf lives

Current international regulatory documents do not provide guidance on how the data from stability studies should be used in the establishment of shelf lives. As an example, for live virus vaccines no limits have been considered for acceptable losses of potency during storage. Providing that the specifications stated on the label are maintained significant inactivation rates are compatible with regulations. This is regarded as unsatisfactory. Problems and experience with a regulative option in Germany are briefly outlined. Control authorities and manufacturers, equally committed to the improvement of vaccine quality, would benefit from internationally harmonized acceptability limits for storage-associated product modifications. Stability criteria for antigen conjugates or for the binding of antigens to adjuvants might also need consideration. It is suggested that appropriate criteria, adapted to scientific and technical progress, be developed for groups of vaccines or individual products.