Children getting the flu vaccine later this year likely won't be able to avoid a shot after a government advisory panel said the popular nasal spray version doesn't work.
Looking at three years of data on infected kids, the panel found decreasing effectiveness of the spray known by its brand name FluMist, which is manufactured by Gaithersburg-based MedImmune.
The Advisory Committee on Immunization Practices, which guides the U.S. Centers for Disease Control and Prevention, recommended that people no longer use it.
The spray makes up just eight percent of the nation's total vaccine supply but about a third of children older than 2 now get it, according to the CDC. About 100,000 students in Maryland — a quarter of those in elementary school —are vaccinated with the nasal spray in clinics every fall.
Schools don't require the vaccination, but it's considered a public safety measure because the flu virus is contagious and sickens and kills thousands of people nationwide every year, said Tiffany Tate, executive director of the Maryland Partnership for Prevention, a non-profit group that works on school immunization programs. Senior citizens, young children and people with compromised immune systems are particularly vulnerable.
The CDC recommends everyone six months and older be vaccinated, and agency officials said they are working with manufacturers to ensure there is enough injectable supply to meet demand. Manufacturers have predicted they'd produce up to 176 million doses this season, with FluMist accounting for about 14 million of them.
"We're grateful we have three months to plan," Tate said. "We're working diligently to make sure the vaccine is available to replace the gap left by FluMist."
The Partnership for Prevention already ordered its doses of spray and now will have to replace them with shots, Tate said. Parents prefer the spray, she said, given how they scrambled last year to find their children doses after a manufacturing shortage caused school clinics to be postponed or canceled. Her group now will work to to educate parents on the safety of the injectable vaccine and the schools' ability to administer it.
The effectiveness of flu vaccine typically fluctuates because it's reformulated annually to match circulating strains. Last season CDC studies showed the injectable vaccine was 63 percent protective against the flu, but the spray was only three percent effective, providing no real benefit.
AstraZeneca, the London-based parent of MedImmune, reported that its studies found the spray to be up to 58 percent effective. It also cited similar findings overseas, where the company plans to continue distributing the vaccine.
The company sold $206 million of FluMist in the United States last year, but after the CDC finding it said it would to take an inventory write-down of approximately $80 million in the second quarter.
"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.," said the company in a statement.
The panel's recommendation to stop using the spray still must be approved by the CDC director to take effect, but that's considerd likely. It's a remarkable turnaround for the vaccine first approved in 2003 and once preferred by the CDC for young children.
But the spray version may be available again in the future if researchers can determine the problem and fix it, said one advisory panel representative, Dr. Kathleen M. Neuzil, a professor of medicine and pediatrics and director of the Center for Vaccine Development at the University of Maryland School of Medicine.
CDC officials are constantly faced with vaccine complications because the flu virus is "predictably unpredictable," she said.
Sometimes it's not a perfect match or a strain mutates or pops up late in the season. The CDC will need time to investigate why this vaccine lost effectiveness, she said.
Neuzil speculated that there could be a manufacturing problem with the spray, which is made of weakened live virus that is sensitive to heat and handling. Or there could be something related to a particularly hardy virus strain called H1N1, for which the spray performed worst.
That strain caused a flu pandemic in 2009 because few people had any immunity to it, and it has been included in the vaccine formulation every year since. Normally a strain sickens people for a few years until the population builds resistance and it is overtaken by another strain.
Perhaps the body's immune system reacts differently to the FluMist as compared with the injection, which is made up of dead viruses, she said.
One thing remains constant, Neuzil said. The University of Maryland Medical Center fills with sick children every season and everyone should "grin and bear it" and get the shot.
The vaccine doesn't prevent all flu cases, she said, but it usually prevents people from getting very sick.
"Luckily we have an alternative with injections," said Neuzil, noting most vaccines come in only one form. "It may be less convenient, but children get shots for many, many other pathogens."
The call for switching solely to injectable vaccination was echoed by the American Academy of Pediatrics, which agreed with the advisory panel that the spray not be used this season.
"We do understand this change will be difficult for pediatric practices who were planning to give the intra-nasal spray to their patients, and to patients who prefer that route of administration," said Dr. Karen Remley, the association CEO and executive director, in a statement. "However the science is compelling that the inactivated vaccine is the best way to protect children from what can be an unpredictable and dangerous virus."