August 19, 2015
CDC Urges Widespread Flu Vaccination Before Season’s Onset

Atlanta—Pharmacists have less than 2 months to gear up for the next influenza season.

The CDC urges pharmacists and other healthcare providers to offer influenza vaccine by October so that as many Americans as possible can be immunized before the onset of influenza season. Vaccines should continue to be offered as long as influenza viruses are circulating, according to the article published in a recent Morbidity and Mortality Weekly Report.

Routine annual influenza vaccination is recommended for all people 6 months of age and older who do not have contraindications. Children aged 6 months through 8 years who require two doses should receive their first dose as soon as possible after vaccine becomes available, and the second dose after 4 weeks or later. The algorithm for determining the appropriate number of doses for those children has been updated.

The vaccine should not be given too early, the CDC cautions, pointing to research indicating that antibody levels can decline after 6 months, especially in adults 65 and older. On the other hand, purposely holding off on immunization also is not recommended.

“While delaying vaccination might permit greater immunity later in the season, deferral might result in missed opportunities to vaccinate, as well as difficulties in vaccinating a population within a more constrained time period,” public health officials suggest. “Vaccination programs should balance maximizing the likelihood of persistence of vaccine-induced protection through the season with avoiding missed opportunities to vaccinate or vaccinating after influenza virus circulation begins.”

For 2015-2016, U.S.-licensed trivalent influenza vaccines will contain hemagglutinin (HA) derived from an A/California/7/2009 (H1N1)-like virus, an A/Switzerland/9715293/2013 (H3N2)-like virus, and a B/Phuket/3073/2013-like (Yamagata lineage) virus; the influenza A (H3N2) and the influenza B virus strains differ from those used during the 2014-2015 season. Quadrivalent influenza vaccines will contain these vaccine viruses plus a B/Brisbane/60/2008-like (Victoria lineage) virus, which is unchanged from the 2013-2014 and 2014-2015 seasons.

Not only have components of the vaccine changed, but so have some of the mechanisms to deliver it. New FDA approvals for influenza vaccine products include the following:

• Afluria, an inactivated influenza vaccine from bioCSL, Inc. of King of Prussia, Pennsylvania, for intramuscular administration via the Stratis needle-free jet injector, produced by PharmaJet, Inc. of Golden, Colorado, for persons aged 18 through 64 years. It was approved by the FDA last August.
• An expanded age indication for the use of Flublok, a recombinant influenza vaccine, trivalent [RIV3] from Protein Sciences in Meriden, Connecticut, which was previously approved for persons aged 18 through 49 years. Flublok is now also indicated for adults 50 and older.
• Fluzone Intradermal Quadrivalent from Sanofi Pasteur, Inc., in Swiftwater, Pennsylvania, for persons aged 18 through 64 years. The new formulation is expected to replace the previously available trivalent Fluzone Intradermal for the 2015-2016 influenza season.

The CDC says that both live attenuated influenza vaccine (LAIV) and inactivated influenza vaccine (IIV) are demonstrated to be effective in children and adults, and, in a change from last year, currently does not expresses a preference for the live vaccine in children.

“In the absence of data demonstrating consistent greater relative effectiveness of the current quadrivalent formulation of LAIV, preference for LAIV over IIV is no longer recommended,” according to the guidance. “ACIP will continue to review the effectiveness of influenza vaccines in future seasons and update these recommendations if warranted.”

A list of contraindications for LAIV in adults and children has not changed, however.

ACIP also clarified advice on administering flu vaccines to people with allergies to eggs. With the exceptions of recombinant influenza vaccine (RIV3, Flublok) and cell-culture based inactivated influenza vaccine (ccIIV3, Flucelvax), currently available influenza vaccines are prepared by propagation of virus in embryonated eggs, according to the CDC advisory.
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