The Advisory Committee on Immunization Practices (ACIP) on Wednesday voted to once again recommend use of the AstraZeneca's FluMist, reversing its earlier position against the vaccine.
According to the Associated Press, ACIP issues recommendations to CDC, which generally follows the committee's advice and issues it as guidance for providers, hospitals, and insurers.
FluMist, developed by AstraZeneca's MedImmune, is the only nasal spray flu vaccine on the market and is approved for use on healthy people ages two through 49. The spray vaccine differs from the traditional shot-based flu vaccines because it is made using a live but weakened virus, as opposed to a killed virus.
Early studies found that FluMist was highly effective and outperformed traditional shots in kids. In 2014, the ACIP recommended using the nasal spray for children ages two through eight over traditional shots. However, in 2016, the panel retracted its endorsement of FluMist, citing CDC research showing that it was generally ineffective against the 2009 swine flu strain H1N1 that had sickened most flu patients during the previous year.
While the FluMist has remained on the market, ACIP for the past two flu seasons has not issued recommendations advising its use.
An improved vaccine, AstraZenca says
According to STAT News, MedImmune said it has identified the problem with the original H1N1 vaccine formulation and replaced it with a new live virus. MedImmune said it tested the reformulated vaccine by comparing children's immune responses to the reformulated FluMist with the immune responses of children who had received the original formulation. The research showed the reformulated FluMist is more effective, MedImmune said.
However, STAT News noted that it's difficult to test the vaccine's efficacy against H1N1 on a large scale since there's been comparatively little H1N1 flu activity over the past few seasons. In fact, according to STAT News, the only way to test the vaccine's efficacy would be to use it—which would require ACIP approval and a flu season involving sufficient H1N1 activity. CDC's Lisa Grohskopf told the committee, "The effectiveness of this formulation against (H1N1) is not known, and is likely to remain unknown until the next H1N1 predominant season, presuming adequate uptake of vaccine. We can't predict when this will occur."
ACIP votes to recommend—but concerns linger
ACIP on Wednesday voted 12-2 in favor of a neutral recommendation that the nasal spray be offered as an option for the next flu season, AP reports. However, the recommendation doesn't advise that providers use FluMist—only that it was one of multiple flu vaccine options providers could use if they wished.
That said, some ACIP members expressed concerns about recommending the vaccine based on MedImmune's data. Panel member Henry Bernstein—a pediatrics professor at the Zucker School of Medicine at Hofstra/Northwell, who voted against the recommendation—said, "I'm a little concerned about whether it would be interpreted that we're compromising our interpretation of the science."
Another panel member, Edward Belongia of Marshfield Clinic Research Foundation, added, "This is not an easy decision. It's always a challenge to make a decision with incomplete data."
Others expressed concern that if the FluMist vaccine was recommended once again and failed, it could hurt the already-poor reputation attached to flu vaccines. Sean O'Leary, from the Pediatric Infectious Diseases Society, said such a failure during a bad flu season would be "a potential disaster."
Gregory Keenan, AstraZeneca's VP of U.S. medical affairs, praised the decision. "We are pleased that the ACIP has voted in support of a renewed recommendation for FluMist," he said. "[We] look forward to continuing to work with public health authorities to optimize protection against influenza."
However, according to Nancy Messonnier, director of the CDC's national center for immunization and respiratory diseases, the vote might have come too late for widespread use during the next flu season. Many providers have already ordered their vaccinations for next year, she explained, and CDC's Vaccines for Children program has already issued its contracts.
AstraZeneca indicated that it would ask CDC if its selection via the Vaccines for Children program could be increased to include FluMist, a request that Messonnier said was not CDC's "typical approach" but may be considered due to "extenuating circumstances" (Branswell, STAT News, 2/21; Reuters/New York Times, 2/21; AP/New York Times, 2/21).
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