The Centers for Disease Control and Prevention (CDC) has published updates of last year’s recommendations of the Advisory Committee on Immunization Practices (ACIP) for the use of seasonal influenza vaccines. The following is a selection of some of the most pertinent ones.
- Antigenic composition of U.S. seasonal influenza vaccines for 2015-16.
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. These are changes in the influenza A (H3N2) virus and the influenza B virus as compared with the 2014–15 season. Quadrivalent influenza vaccines will contain these vaccine viruses, and a B/Brisbane/60/2008-like (Victoria lineage) virus, which is the same Victoria lineage virus recommended for quadrivalent formulations in 2013–14 and 2014–15.
- New vaccine products.
Among the new products expected to be available for the 2015-16 season, one is of interest because of its novel method of vaccine delivery. Afluria (inactivated influenza vaccine, bioCSL, Inc., King of Prussia, Pennsylvania) uses a needle-free jet injector rather than a needle for intramuscular vaccine delivery. It is approved for adults aged 18 through 64 years for whom it may be delivered either by the Stratis injector or with a sterile needle and syringe — all other inactivated influenza vaccines are approved for administration by sterile needle and syringe only. The Stratis injector is a reusable spring-powered device which injects the vaccine through a single-use sterile needle-free syringe into the deltoid muscle. While local reactions are more frequent with administration by the Stratis injector than in those vaccinated with a sterile needle and syringe, most such reactions resolve within 3 days. Antibody levels after administration by either technique are similar.
- An update of the recommendations for determination of the appropriate number of vaccine doses for children 6 months through 8 years of age (see Figure 1).
The change in vaccine composition for 2015–16 means that for 2015–16, ACIP recommends that children aged 6 months through 8 years who have previously received ≥ 2 total doses of trivalent or quadrivalent influenza vaccine before July 1, 2015, require only 1 dose for 2015–16. The two previous doses need not have been given during the same season or consecutive seasons. Children in this age group who have not previously received a total of ≥ 2 doses of trivalent or quadrivalent influenza vaccine before July 1, 2015, require 2 doses for 2015–16. The interval between the 2 doses should be at least 4 weeks.
- New recommendations for the use of live attenuated influenza vaccine (LAIV) and inactivated influenza vaccine (IIV) when either is available.
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. ACIP will continue to review the effectiveness of influenza vaccines in future seasons and update these recommendations if warranted.
- Influenza vaccination of persons with a history of egg allergy.
With the exceptions of recombinant influenza vaccine (RIV3, Flublok) and cell-culture based inactivated influenza vaccine (ccIIV3, Flucelvax, Novartis, Cambridge, Massachusetts), currently available influenza vaccines are prepared by propagation of virus in embryonated eggs. Nonetheless, severe allergic and anaphylactic reactions are rare. The 2015-16 recommendations are contained in Figure 2.
Source: Centers for Disease Control and Prevention
Abbreviations: IIV = inactivated influenza vaccine, trivalent or quadrivalent; RIV3 = recombinant influenza vaccine, trivalent.
* Persons with egg allergy may tolerate egg in baked products (e.g., bread or cake). Tolerance to egg-containing foods does not exclude the possibility of egg allergy (Erlewyn-Lajeunesse et al., Recommendations for the administration of influenza vaccine in children allergic to egg. BMJ 2009;339:b3680).
† For persons who have no known history of exposure to egg, but who are suspected of being egg-allergic on the basis of previously performed allergy testing, consultation with a physician with expertise in the management of allergic conditions should be obtained prior to vaccination. Alternatively, RIV3 may be administered if the recipient is aged ≥18 years.
Source: Centers for Disease Control and Prevention
The CDC has published updates of last year’s recommendations of the Advisory Committee on Immunization Practices for the use of seasonal influenza vaccines. The following is a selection of some of the most pertinent ones.
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