CDC: 2012-2013 flu vaccine not as effective in elderly

(HealthDay)—Vaccination against influenza for the 2012/2013 flu season appears to be moderately effective in reducing the need for outpatient medical attention, but the effect is lower in the elderly, according to research published in the Feb. 22 issue of the U.S. Centers for Disease Control and Prevention's Morbidity & Mortality Weekly Report.

Lisa Jackson, M.D., of the CDC in Atlanta, and colleagues analyzed data from the U.S. Influenza Vaccine Effectiveness Network to estimate vaccine effectiveness (VE) for the 2012/2013 influenza season.

The researchers estimated the overall VE against influenza A and B to be 47 and 67 percent, respectively, or 56 percent overall, which was close to the interim estimate of 62 percent. When stratified by age group, the estimates for VE against influenza A (H3N2) and B infections were mostly consistent across age groups, with the exception that lower VE against influenza A (H3N2) was seen among adults aged 65 and older. These findings suggest vaccination against influenza reduces the risk of illness requiring outpatient medical visits by one-half to two-thirds for most people, although VE was lower and not statistically significant among people aged 65 and older.

"Antiviral medications should be used as recommended for treatment of suspected influenza in certain patients, including those aged ≥65 years, regardless of their influenza vaccination status," the authors write.