Overview of Influenza Vaccinations, 2012/2013

The Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices has released its recommendations and overview for the 2012/2013 influenza season. The report appeared in the Morbidity and Mortality Weekly Report [2012;61(32):613-618].

US influenza vaccines for 2012/2013 will contain A/California/7/2009 (H1N1)-like, A/Victoria/361/2011 (H3N2)-like, and B/Wisconsin/1/2010-like (Yamagata lineage) antigens. The influenza A(H3N2) and B antigens differ from the respective 2010/2011 and 2011/2012 seasonal vaccine antigens. The influenza A(H1N1) vaccine virus strain is derived from an influenza A(H1N1)pdm09 (2009[H1N1]) virus and was included in the 2009(H1N1) monovalent pandemic vaccine as well as the 2010/2011 and 2011/2012 seasonal vaccines.

Routine annual influenza vaccination is recommended for all persons ≥6 months of age. To permit time for production of protective antibody levels, vaccination optimally should occur before onset of influenza activity in the community. Therefore, vaccination providers should offer vaccination as soon as vaccine is available. For children 6 months through 8 years of age, 2 doses of influenza vaccine (administered a minimum of 4 weeks apart) during their first season of vaccination to optimize immune response are recommended. There are 2 recommended approaches to vaccinating children in this age range:

• The first approach takes into consideration only doses of seasonal influenza vaccine received since July 1, 2010. This recommendation is harmonized with that of the American Academy of Pediatrics. This approach has the advantage of simplicity, particularly in settings in which ascertaining vaccination history before the 2010/2011 season is difficult. Using this approach, children 6 months through 8 years of age need only 1 dose of vaccine in 2012/2013 if they received a total of ≥2 doses of seasonal vaccine since July 1, 2010. Children who did not receive a total of ≥2 doses of seasonal vaccine since July 1, 2010, require 2 doses in 2012/2013.
• In settings where adequate vaccination history from prior to the 2010-2011 season is available, this approach may be used. If a child 6 months through 8 years of age is known to have received at least 2 seasonal influenza vaccines during any previous season, and at least 1 dose of a 2009(H1N1)-containing vaccine (either 2010/2011 or 2011/2012 seasonal vaccine or the monovalent 2009[H1N1] vaccine), then the child needs only 1 dose for 2012/2013.

There are different indications for the multiple vaccines that will be available for this upcoming season. TIV preparations, with the exception of Fluzone^® Intradermal (Sanofi Pasteur), should be administered intramuscularly. For adults and older children, the deltoid is the preferred site. Infants and younger children should be vaccinated in the anterolateral thigh. For intramuscular TIV preparations, children 6 through 35 months of age should receive 0.25 mL per dose; those ≥36 months of age should receive 0.5 mL per dose via a single-dose, prefilled microinjection syringe. The preferred site for administration is over the deltoid muscle. The intranasally administered live-attenuated influenza vaccine (LAIV), FluMist^® (MedImmune), is indicated for healthy, nonpregnant persons 2 through 49 years of age. No preference is indicated for LAIV versus TIV in this age group.

Because all currently available influenza vaccines are prepared by means of inoculation of virus into chicken eggs, ACIP recommends that people with a history of egg allergy who have experienced only hives after exposure to egg should receive the influenza vaccine, with the following additional safety measures:

• Because studies published to date involved use of TIV, TIV rather than LAIV should be used.
• Vaccine should be administered by a healthcare provider who is familiar with the potential manifestations of egg allergy.
• Vaccine recipients should be observed for at least 30 minutes for signs of a reaction after administration of each vaccine dose.

Patients who have experienced severe allergic reactions to egg should consult a physician before receiving any influenza vaccine.