Research shows FluMist failed to protect children from the flu virus.

A June 2016 study by the Advisory Committee on Immunization Practices with the Centers for Disease Control and Prevention rescinded its prior endorsement of a popular nasal spray version of the flu vaccine.

FluMist, developed by AstraZeneca, makes up less than 10 percent of all vaccine doses produced each year. Nasal sprays comprised around one-third of the vaccinations given to children.

Epic downturn

FluMist is the only nasal spray flu vaccine available and approved for use on healthy people ages 2 through 49. It’s made using a live but weakened virus — compared to a killed virus found in traditional flu shots.

FluMist initially outperformed traditional shots for kids. The CDC committee recommended using the nasal spray for children ages 2 through 8 in 2014.

However, new findings show over the past three flu seasons that FluMist was ineffective against the majority of flu strains.

The nasal spray was just 3 percent effective during last flu season, which means “no protective benefit could be measured,” according to the CDC. In contrast, flu shots were more than 60 percent effective for kids ages 2 through 17.

Search for answers

The latest CDC study unfortunately could not pinpoint how or why nasal sprays have become ineffective.

A CDC flu expert says the drugmaker’s move to use four strains of flu — rather than three — may have lowered the body’s response to one of the strains.

In a June 2016 statement, AstraZeneca maintained that the CDC’s findings “contrast with studies by AstraZeneca as well as independent findings by public health authorities in other countries.”

The company says FluMist was 46 to 58 percent effective against the circulating flu strains during the 2015 to 2016 flu season. “AstraZeneca is working with the CDC to better understand its data to help ensure eligible patients continue to receive the vaccine in future seasons in the U.S.,” the company said.

Possible vaccine shortages

Industry experts say the CDC recommendation could hinder efforts to vaccinate kids in the next flu season. Many health care providers order flu vaccines one year beforehand.

The experts believe the U.S. will not see major shortages, but scattered local shortages could appear.

The American Academy of Pediatrics says it “will be working with the CDC and vaccine manufacturers to make sure pediatricians and families have access to appropriate vaccines, and to help pediatricians who have already ordered intranasal vaccines.”

“It’s unfortunate that we may not have a non-injectable form of flu vaccine available for people who prefer nasal sprays,” said Julie Koch, infection prevention manager with Salem Health. “However, the flu shot is still available and recommended for everyone six months of age and older. We will continue to monitor the situation and adjust accordingly if the CDC informs us of any changes.”