11.4 Vaccine safety
Horton, R. (2004) ‘The lessons of MMR’, The Lancet, 363, 6 March 2004, pp 747–749 Elsevier. Copyright © 2004 Elsevier.
In a review of the unintended effects associated with MMR, Jefferson and colleagues10 found that the reporting of safety outcomes in MMR vaccine studies was inadequate. Here is a constantly repeated scenario in health-technology assessment (another example: the row over the safety of calcium-channel blockers). A product undergoes limited testing for efficacy and safety. It is licensed. A signal of concern is thrown up.
There is no valid set of safety data to which one can turn to answer these queries. Public concern grows and confidence in the technology may be jeopardised. Appropriate studies are hastily completed to confirm or refute the original signal of potential risk. An answer eventually comes, but too late to have prevented a great deal of anxiety.
Jefferson has suggested a solution to this problem.11 He recognises that vaccines pose particular challenges to investigators given their frequently universal coverage, which precludes the possibility of any controlled long-term experimental assessment. Instead, he proposes creating a library of evidence, drawing together widely dispersed data from published papers, manufacturers’ technical reports, and researchers’ personal files. In this way, loss of crucial information would be minimised and gaps in existing evidence could be identified and filled early on. This idea is sensible and deserves further consideration.