Influenza vaccination: policy versus evidence: No gap between policy and evidence

doi:10.1136/bmj.39024.451389.FA

BMJ 2006;333:1020 (11 November), doi:10.1136/bmj.39024.451389.FA

Letters

Influenza vaccination: policy versus evidence

No gap between policy and evidence

The first 150 words of the full text of this article appear below.

Jefferson believes that his systematic reviewsshow that influenza vaccines "have little or no effect on theeffects measured."¹ He wonders why there is a gap between evidenceand policy.

Jefferson identifies three reasons why his evidencecontradicts policy.

Firstly, policy relies heavily on non-randomisedstudies. Yet his preference for randomised controlled trialsis based on historical, pragmatic, and heuristic reasons andcannot be justified on epistemological grounds alone.² He arguesthat heterogeneity among studies and study years³ can be overcomeby "averaging" outcomes over several years, and finds observationalstudies yield relative risk reductions that are statisticallysignificant.

Secondly, he cites the lack of evidence of vaccinationon effects "at the centre of campaign objectives," yet he documentssuch evidence for older adults, barely fails to show it foryounger adults, and is unable to consider influenza-relatedotitis media, a frequent complication in young children.

Thirdly, he is concerned . . . [Full text of this article]

David S Fedson, retired physician¹, Kristin L Nichol, professor of medicine²

¹ 01630 Sergy Haut, France dfedson@wanadoo.fr , ² University of Minnesota