First Quadrivalent Influenza Vaccine Gains FDA Approval

The FDA's late February approval of the first quadrivalent influenza vaccine adds to the weapons family physicians can use to prevent seasonal influenza.

MedImmune LLC's FluMist Quadrivalent is a live, attenuated influenza vaccine that, like the manufacturer's trivalent product, is administered as a nasal spray and is approved for use in people ages 2 through 49 years. The vaccine is the first to contain four strains of the influenza virus -- two influenza A and two influenza B lineage strains.

According to an FDA news release, the additional B lineage virus strain was included to increase the likelihood of adequate protection against circulating influenza B strains.

Karen Midthun, M.D., director of the FDA's Center for Biologics Evaluation and Research, noted in the release that illness caused by influenza B virus affects young and school-aged children more than any other population.

"A vaccine containing the four virus strains most likely to spread and cause illness during the influenza season offers an additional option to aid in influenza prevention efforts," she said.

Specifically, the quadrivalent vaccine will contain an influenza B strain from the B/Yamagata/16/88 lineage and a strain from the B/Victoria/2/87 lineage. The current 2011-12 trivalent vaccine contains a strain from the B/Victoria lineage, and the newly selected 2012-13 trivalent vaccine will contain a strain from the B/Yamagata lineage.

According to a Feb. 29 MedImmune press release, during five of the past 10 flu seasons, the predominant circulating influenza B lineage virus was different from the B lineage strain selected for inclusion in the trivalent vaccine.

Like the trivalent FluMist, the prescribing information for FluMist Quadrivalent (25-page PDF; About PDFs) states that the vaccine is contraindicated in the following individuals:

In addition, children and adolescents should not be given aspirin for four weeks after receiving FluMist Quadrivalent unless clearly needed.

The CDC's Advisory Committee on Immunization Practices could take up the question of whether to recommend the quadrivalent vaccine for routine use as early as its June 20-21 meeting.