Atlanta—Pharmacists likely will have one less weapon in their arsenal to battle influenza this season. That’s based on the decision of a group that advises the CDC.

The CDC’s Advisory Committee on Immunization Practices (ACIP) recently voted that live attenuated influenza vaccine (LAIV), delivered as a nasal spray, should not be used during the 2016-2017 flu season.

Annual flu vaccination for all Americans 6 months old or older—with either the inactivated influenza vaccine (IIV) or recombinant influenza vaccine (RIV)—is still recommended.

The vote by ACIP is based on data showing poor or relatively lower effectiveness of LAIV from 2013 through 2016.

Preliminary data on the effectiveness of LAIV among children 2 years through 17 years during the 2015-2016 season, which became available in late May from the U.S. Influenza Vaccine Effectiveness Network, indicated the estimate for LAIV vaccine effectiveness (VE) among study participants in that age group against any flu virus was 3%. That essentially meant no protective benefit could be measured, according to the panel. On the other hand, IIV, given as shots, had a VE estimate of 63% against any flu virus among children 2 years through 17 years.

LAIV, which contains live, weakened influenza viruses, also had poor and/or lower than expected VE for the two seasons prior to the most recent, according to the CDC. Why that occurred is not known, since LAIV VE data before and soon after licensure in 2003 suggested it was either comparable to, or better than, IIV. Vaccines containing live viruses usually spur a stronger immune response than vaccines with inactivated virus.

As many as 171 million to 176 million doses of flu vaccine, in all forms, were expected to be available in the United States during the 2016-2017 season. About 8% of that is in the form of LAIV/nasal spray flu vaccine, which is sold as FluMist Quadrivalent and it is produced by MedImmune, a subsidiary of AstraZeneca, according to the CDC.

Public health officials pointed out that the change could affect vaccine providers who have already placed orders for immunization products, with the greatest effect expected for pediatricians and other vaccine providers for children. Data from recent seasons suggests nasal spray flu vaccine accounts for about one-third of all flu vaccines given to children. 

The ACIP recommendation must be reviewed and approved by CDC’s director before it becomes CDC policy. Final annual recommendations on the prevention and control of influenza with vaccines will be published in an issue of the Morbidity and Mortality Weekly Report (MMWR) in late summer or early fall, the CDC said.

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