FluMist, the vaccine approved in 2003 by the U.S. Food and Drug Administration, is administered by a single spritz in each nostril. Last year (2016), a committee of experts on immunization advised the U.S. Centers for Disease Control and Prevention (CDC) that FluMist isn’t effective against the H1N1 flu virus that has been circulating for the past few years. As a result, the CDC advises that kids are better off getting a regular flu shot, which is 63 percent effective, compared to only three percent for FluMist.
FluMist was popular not only because it provided protection without the need for an injection, but also because in years past it was viewed as more effective than the shot. FluMist is the only nasal spray flu vaccine on the market. It is a live, attenuated (weakened) virus as opposed to the inactivated virus given in flu shots.
According to the CDC, the effectiveness of the flu vaccine, which varies widely from season to season, can be affected by such factors as the characteristics of the person being vaccinated, the similarity between vaccine viruses and circulating viruses, and even which vaccine is used. But the agency reported that the reason for the poor performance of FluMist during the last flu season (2015-2016) isn’t entirely known.
The problem with flu vaccines in general is that they have to be reworked every year to keep up with mutations in the flu virus in circulation. These mutations can occur faster than vaccines can be developed and produced.
One school of thought about why FluMist didn’t work during the 2015-2016 flu season holds that the immune system of kids who received it three years in a row may not make enough antibodies in response to it.
The result of this is that kids – and injection-averse adults – who still need protection against the flu in 2017 will need to have shots. Possibly, FluMist will work better in the future against new strains of the flu virus or even against mutations of H1N1.
The CDC currently recommends flu shots for everyone six months of age or older. I recommend them for those over 65, as well as for anyone with a weakened immune or respiratory system, nursing home residents, and health care workers who have regular contact with patients. Pregnant women whose last two trimesters fall during flu season (generally November to April) might also consider getting the shot.
Andrew Weil, M.D.
“ACIP votes down use of LAIV for 2016-2017 flu season.” U.S. Centers for Disease Control and Prevention, June 22, 2016. www.cdc.gov/media/releases/2016/s0622-laiv-flu.html