Flu Vaccine Doesn't Reduce Pneumonia Risk in Elderly
Benefits of influenza vaccination may have been overstated in the past
FRIDAY, Aug. 1 (HealthDay News) -- Elderly people are at a similar risk of developing pneumonia during the flu season whether or not they have been vaccinated against influenza, researchers report in the Aug. 2 issue of The Lancet.
Michael L. Jackson, Ph.D., of the Group Health Center for Health Studies in Seattle, and colleagues conducted a study of 1,173 people aged 65 to 94 years who had either outpatient or inpatient community-acquired pneumonia, as well as two randomly selected controls for each case, matched for age and sex.
After adjusting for the presence of comorbidities, as well as their severity, there was no difference in the risk of developing community-acquired pneumonia among those who had been vaccinated against influenza versus those who had not been vaccinated. The investigators attribute this to two possible causes: that only a small proportion of pneumonia cases in this population are caused by influenza, or that the vaccine is not effective in reducing the risk of influenza infection among the elderly.
"These two possibilities have quite different implications for vaccine development and vaccination recommendations," the authors write. "Differentiation between them will need studies with laboratory-confirmed endpoints, such as pneumonia or serious respiratory outcomes after a confirmed influenza infection."
One of the study authors is a consultant to Sanofi Pasteur and Novartis, both of which manufacture the flu vaccine.