Placebo-controlled randomised trials have shown that the influenza vaccine is effective in younger adults but few trials have included older people despite the majority of influenza-related deaths occurring in those aged over 70. Recent mortality studies have failed to show reductions in influenza-related mortality since 1980 even though uptake of the vaccine has risen from 15% to 65%. It is also noted that observational studies that do report a benefit often contain a substantial and unadjusted selection bias.
The authors conclude that the remaining evidence is insufficient to indicate the magnitude of the mortality benefit but they also state that the current vaccination programme should continue because "even a partly effective vaccine would be better than no vaccine at all".
Action: Clinicians should be aware of this review and the conclusion that vaccination is still recommended. Patients may need some reassurance if this paper is reported in the general media.