Feb. 26, 2015 -- It’s no secret this year’s flu shots didn’t work as well as doctors had hoped. But the news got worse Thursday when the CDC revised its estimates of the flu vaccine’s effectiveness downward even further, from 23% to 18%.
That means for all ages, getting vaccinated cut the risk of needing medical treatment for flu symptoms by just 18%.
“That’s crummy, at best. This year was a bum year,” says William Schaffner, MD, an infectious disease expert and a professor at the Vanderbilt University School of Medicine in Nashville, TN.
And there’s more bad news: Early numbers show that for the second flu season in a row, the FluMist nasal spray, aimed mainly at children, didn’t work at all for kids ages 2 through 8.
That was a bit awkward for the CDC, which had just advised doctors that they choose the nasal spray over the shot for younger kids. Previous studies had suggested that FluMist was more protective than injections for kids in this age group.
Today the agency's advisory committee changed its position, telling doctors to use either kind of vaccine in children, with no particular preference for the nasal spray.
The vaccine-effectiveness percentage is just an average. The real effectiveness probably sits in a range between 6% and 29%, says Brendan Flannery, PhD, of the Center for Immunization and Respiratory Diseases at the CDC.
When the vaccine is a good match to the strains of flu making people sick, vaccine effectiveness has been as high as 60%.
This season’s dominant flu strain, H3N2, is different from the strains included in the flu vaccine, though.
So far this season, 86 children have died of the flu, and more than 13,000 people have been hospitalized with it, according to the CDC. The highest rate of hospitalizations is in adults older than 65. Most adults who've had to go to the hospital have had at least one underlying medical condition.
Experts say even though this flu season’s vaccine wasn’t up to par, people shouldn’t give up on getting their annual flu shots.
source : Flu Vaccine Just 18% Effective This Year