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Sorry. Nasal spray flu vaccine doesn’t work, says CDC panel

REUTERS/Carlos Barria
The evidence shows that FluMist is ineffective at protecting people against the flu, particularly children aged 2 to 17.

The “nasal spray” influenza vaccine, used by millions of Americans in recent years, should not be administered during the coming flu season, an advisory panel to the Centers for Disease Control and Prevention (CDC) has announced.

The panel’s members — the Advisory Committee on Immunization Practices (ACIP) — came to that conclusion after reviewing all the latest scientific data regarding this popular form of the flu vaccine, which is sold under the brand name FluMist.

The evidence clearly shows, they said, that FluMist is ineffective at protecting people against the flu, particularly children aged 2 to 17.

Government officials say they intend to work with vaccine manufacturers throughout the summer to make sure that enough of the injectable form of the vaccine (the traditional “flu shot”) is available to meet the demand when the 2016-2017 flu season gets underway this fall. 

Meeting that demand may be a bit of a scramble. In recent years, FluMist has accounted for about a third of all flu vaccines given to children.

More than a decade

FluMist consists of an attenuated (weakened) form of influenza virus, unlike flu shots, which are made from a dead virus.

The FDA first approved FluMist in 2003, and some 90 million doses have been distributed in the United States since then, according to the CDC. The maker of the vaccine, MedImmune, a subsidiary of AstraZeneca, had projected it would be supplying as many as 14 million doses for the 2016-2017 flu season. That would have been about 8 percent of the 171 to 176 total doses of influenza vaccine that the CDC estimates will be distributed this coming flu season.

The FDA’s approval of FluMist was based on early studies that showed it to be effective. But more recent data — specifically from the past three flu seasons — found that FluMist had a vaccine effectiveness rate so low as to be inconsequential. During the 2015-2016 flu season, for example, the rate among children aged 2 to 17 was an estimated 3 percent.

In other words, it provided essentially no protection against the flu.

By comparison, traditional flu shots were about 63 percent effective in children during last year’s flu season.

The ACIP’s decision about FluMist is only an advisory one, although it’s highly likely, the CDC will adopt it later this summer.

The American Association of Pediatrics has already announced its support of the decision. 

A disappointment

The ACIP’s decision is “disappointing, but not completely surprising,” said Kris Ehresmann, director of infectious disease epidemiology at the Minnesota Department of Health, in a phone interview with MinnPost. “Influenza virus poses a lot of challenges. It’s a wily virus.”

Flu viruses are constantly changing, she explained. It’s the reason why we need to get a new flu vaccine each year.

“While we’re disappointed that this particular tool won’t be available, there are other vaccines that will be available,” Ehresmann said.

Adults who dislike being jabbed with a needle may want to talk with their doctor about receiving a subcutaneous version of the flu shot, she added. It uses a smaller needle, and injects the vaccine into the fatty tissue just under the skin rather than into muscle.  

Ehresmann, who served as an ACIP expert from 2008 to 2012, also stressed that the committee’s decision regarding FluMist is based on the nasal vaccine’s less-than-optimal effectiveness. “It had nothing to do with the safety of the vaccine,” she said.

Scientists and health officials work hard to make sure that each year’s influenza vaccine is as effective as possible, Ehresmann added. 

“We are continuously looking at the science of influenza vaccines,” she said. “When we make a recommendation for a flu shot, it’s not based on data from 70 years ago. We’re looking at it every single season. So while it’s disappointing for the last few seasons that we didn’t see the effectiveness that we wanted, people need to be reassured that this is constantly being evaluated.”

“It’s a continuous evaluation process,” she added. “That’s what this [ACIP decision] reflects. And that’s actually a good thing.”

For more information: You’ll find more about the influenza vaccine at both the CDC and MDH websites.

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