On message, off target

摘要

The cause of science-based policy was not helped late last month when the presumptive Republican candidate for the US presidency, John McCain, promoted the discredited notion that a preservative in vaccines causes autism. Such statements have power, as Anna Pearce and her colleagues remind us in the online edition of the British Medical Journal (A. Pearce et al. Br. Med. J. doi: 10.1136/ bmj.39489.590671.25; 2008). They find that, following the 1998 scare in Britain, when autism was baselessly linked to the triple vaccination for measles, mumps and rubella, uptake by parents, having bottomed out at 79%, has now climbed to 89% - but still falls below the 95% level required for herd immunity.