The influential Advisory Committee on Immunization Practices (ACIP) voted 12-2 on Wednesday to put the nasal spray back on its list of available vaccines.
The vote comes during a lengthy and punishing flu season in the U.S., where the effectiveness of available flu vaccines was low for most age groups. Only young children have seen substantial protection against the most common strain of the flu this year.
It was a guarded “yes," given that doctors won’t know for sure if it works better than before -- or better than other vaccine options -- until it's widely used again during an actual flu season.
The committee first voted to remove the word “recommended” from its statement, which is formally known as a recommendation. Instead, members voted simply to say FluMist was an option.
The ACIP has been burned by FluMist before.
In 2014, the committee advised doctors to choose FluMist over injectable vaccines for healthy children after data seemed to suggest that it was more effective for them.
The committee backed off that statement in 2015 after studies showed that the inhaled vaccine was less effective that the shot. In 2016, the ACIP took the added step of saying FluMist wasn’t recommended at all because it hardly worked. That effectively ended insurance reimbursement for this option.
FluMist has been in the doghouse for two flu seasons: 2016-2017 and 2017-2018.
The committee voted after hearing new data from the MedImmune, the manufacturer of FluMist, and seeing the CDC’s comprehensive meta-analysis -- a study of studies -- on the effectiveness of FluMist and flu shots in the U.S. and Europe.
MedImmune said it had fixed a problem with one of the “A” strains included in the vaccine. The new version includes a different H1N1 strain -- A /Slovenia -- which appeared to boost the numbers of antibodies kids made to fight the flu in a small clinical trial that compared the new FluMist formula with the old one. It also appeared to increase viral “shedding” in kids who got the new version.
Just like a dog or cat sheds hair, the human body gives off, or “sheds,” flu virus when infected. FluMist contains weakened, but live flu strains that infect the body enough to provoke a response from the immune system, but aren’t meant to make a person sick.
The manufacturer argued that more viral shedding suggested that the virus was activating the immune system more strongly than previous versions. They also noted that FluMist continues to work well for children in the U.K. and Europe.
“We always have to make decisions based on the best available science that we have,” said committee member Edward Belongia, MD, director of the Center for Clinical Epidemiology and Population Health at the Marshfield Clinic Research Institute. “It looks like they’ve found the source of the problem,” he said. He voted to restore FluMist to the list of available options.
Committee member Henry Bernstein, DO, a pediatrician at Cohen Children’s Medical Center in New Hyde Park, NY, was one of the “no” votes. He said he wasn’t convinced that viral shedding was a good test of flu protection.
“I’m worried that we had two strikes, and [the 2018-2019 flu season] would be the third strike,” he said.
Other members were swayed by CDC data that showed that vaccine coverage dipped 2% in children after FluMist was cast aside.
For some kids, they reasoned, FluMist might be the only way they’d be immunized at all.
“This is not an easy decision,” Cynthia Pellegrini, senior vice president of public policy and government affairs for the March of Dimes, said during the discussion before the vote.
“Let’s put it out there and let clinicians and parents decide what to give their kids,” she said. She voted yes.