Current Flu Vaccine Half as Effective as Previous Years
Friday, January 30, 2015 10:43 PM

People receiving this year's seasonal influenza vaccine are twenty-three percent less likely to seek medical treatment for flu-type symptoms relative to unvaccinated individuals, according to an interim CDC estimate based on reports submitted so far for the current season.  That's less than half the "vaccine effectiveness" calculated for the vaccines deployed in recent seasons.  But the new estimate, published online in Morbidity and Mortality Weekly Report, is the first time the agency has put a number to the reduced effectiveness.

Authors of the report noted that their interim estimate came earlier than in previous years, because of the early onset of significant flu cases last fall.  Last week, the CDC called for immediate treatment with influenza antiviral drugs in all high-risk patients presenting with possible flu, without waiting for confirmatory testing.