From: bigvince on
1: Lancet Infect Dis. 2007 Oct;7(10):658-66....

Mortality benefits of influenza vaccination in elderly people: an
ongoing controversy.
Simonsen L, Taylor RJ, Viboud C, Miller MA, Jackson LA.

National Institute of Allergy and Infectious Diseases, National
Institutes of Health, Bethesda, MD, USA. iph...(a)

Influenza vaccination policy in most high-income countries attempts to
reduce the mortality burden of influenza by targeting people aged at
least 65 years for vaccination. However, the effectiveness of this
strategy is under debate........

........Recent excess mortality studies were unable to confirm a
decline in influenza-related mortality since 1980, even as vaccination
coverage increased from 15% to 65%. Paradoxically, whereas those
studies attribute about 5% of all winter deaths to influenza, many
cohort studies report a 50% reduction in the total risk of death in
winter--a benefit ten times greater than the estimated influenza
mortality burden. New studies, however, have shown substantial
unadjusted selection bias in previous cohort studies........
.....We conclude that frailty selection bias and use of non-specific
endpoints such as all-cause mortality have led cohort studies to
greatly exaggerate vaccine benefits. The remaining evidence base is
currently insufficient to indicate the magnitude of the mortality
benefit, if any, that elderly people derive from the vaccination

PMID: 17897608 [PubMed - indexed for MEDLINE]