Do flu vaccines save the lives of older people?

Vaccinating older people against flu should reduce hospital admissions and deaths, but earlier studies struggled to show this: although vaccination of older people rose from 15% in 1980 to 65% in the mid-1990s, no clear fall in deaths was seen. Most Western countries still recommend vaccinating all older people, partly because it would be unethical to give some people the vaccine and others a placebo, so scientists have to analyse data from whole populations.

A new study, published in the New England Journal of Medicine on 4 October 2007, used medical records from the United States for ten consecutive flu seasons, starting in 1990, for people aged 65 and over. It recorded who was vaccinated, who was admitted to hospital and who died.

During flu seasons, vaccinated people were 27% less likely to be admitted to hospital with pneumonia or flu, and about half as likely to die, compared with unvaccinated people. The researchers checked whether vaccinated people were simply healthier to begin with, and say this didn't explain the results, although this question remains debated.

The flu vaccine is still recommended every year for people aged 65 and over and for others at higher risk.