In July 2011, the FDA announced its approval of the vaccine formulation for the 2011-2012 season (
Figure).
12 The 3 viral strains selected for the vaccine are the following: A/California/7/09 (H1N1)-like virus; A/Perth/16/2009 (H3N2)-like virus; and B/Brisbane/60/2008-like virus.
12 These are the same strains that were used in the 2010-2011 season.
10 As always, it is possible that the selected strains may not match the actual influenza viruses that circulate during the influenza season. However, even if the vaccine strains are not an exact match to the circulating virus, the vaccine may reduce the severity of illness.
Between last season and this season, 2 new types of influenza vaccines became available—Fluzone High-Dose and Fluzone Intradermal.
3 Fluzone High-Dose (Sanofi Pasteur Inc; Swiftwater, Pennsylvania) was introduced in the 2010-2011 influenza season. This vaccine, which contains 4 times the amount of antigen against the 3 selected strains as does regular-dose Fluzone, is indicated for use in adults aged 65 years or older.
10,12,13 The high dose is designed to benefit elderly patients, who do not respond to influenza vaccines as well as young, healthy individuals. Fluzone High-Dose induced higher antibody titers than the regular-dose formulation when measured by HA inhibition and neutralizing antibodies.
13-15 Local adverse events (eg, redness, swelling, pain) were more common in patients given the high-dose Fluzone formulation than in patients given regular-dose Fluzone.
13-15 The ACIP currently does not recommend using Fluzone High-Dose over regular-dose influenza vaccine because no randomized, controlled studies are available to demonstrate greater clinical efficacy of the high-dose formulation.
Fluzone Intradermal (Sanofi Pasteur Inc) is being introduced in the 2011-2012 influenza season.
16 This vaccine contains 27 μg of antigen in 0.1 mL of vaccine, compared to 45 μg of antigen in 0.5 mL of regular influenza vaccine. It is available in a special syringe to allow it to be administered intradermally. Fluzone Intradermal is indicated for use in adults aged 18 to 64 years.
16 In safety and antibody titer studies comparing Fluzone Intradermal to regular Fluzone, antibody titers were not inferior with intradermal administration, though sero-conversion rates against influenza type B virus were slightly lower with the intradermal vaccine.
16 Injection site adverse reactions, though not serious, were also more common with intradermal administration.
16