Each year, seasonal flu kills approximately 36,000 people in the United States, most over age 70.Yet little is known about the benefit of influenza vaccine in older seniors.
Randomized, placebo-controlled clinical trials involving seniors have not been large enough to reveal how well the vaccine can prevent death in this age group.
In an article in the October issue of The Lancet Infectious Diseases, now available online, researchers from the National Institutes of Health (NIH) describe how sources of bias in other, non-randomized studies have inadvertently resulted in an exaggeration of the flu vaccine’s value in preventing flu deaths in the elderly. The authors point to the need for better flu vaccines for seniors, and other strategies to reduce severe influenza outcomes among this age group.
The authors emphasize that even a less-than-ideal influenza vaccine is better than none at all, and that this age group should continue to get a seasonal flu shot. Better vaccines are needed, however, and NIAID supports research to develop new and improved vaccines.
In the meantime, the researchers suggest intensive study of several approaches to reduce influenza-related deaths among the elderly.
Vaccinate more people in all age groups to indirectly better protect the elderly
Identify and vaccinate the frail elderly who are at greatest risk of death from flu
Use antiviral drugs more aggressively to treat and prevent flu in seniors and their contacts
The researchers also outline new epidemiological methods that may aid in establishing a more accurate picture of the impact on mortality of flu vaccination in the elderly.
The paper’s lead author is Lone Simonsen, Ph.D., formerly of the National Institute of Allergy and Infectious Diseases (NIAID), part of the NIH. Other authors include Mark A. Miller, M.D., of NIH’s Fogarty International Center, and Lisa A. Jackson, M.D., of Group Health Center for Health Studies, Seattle.
ARTICLE: “Mortality benefits of influenza vaccination in elderly people: an ongoing controversy,” by L. Simonsen et al. The Lancet Infectious Diseases 7: 658–66 (2007).