High-dose flu vaccine better protects HIV-infected adults

Noah McKittrick, M.D., from University of Pennsylvania in Philadelphia, and colleagues randomly assigned 190 HIV-infected persons (older than 18 years) to receive either a standard dose (15 mcg of antigen per strain; 93 participants) or a high dose (60 mcg/strain; 97 participants) of the influenza trivalent vaccine. The rate of seroprotection was assessed, defined as antibody titers of 1:40 or greater on the hemagglutination inhibition assay 21 to 28 days after vaccination. Seroconversion, defined as a greater than four-fold increase in antibody titers, and the geometric mean antibody titer were also assessed.

The researchers found that, in the high-dose group, seroprotection rates were higher for H1N1 (96 versus 87 percent; P = 0.029), H3N2 (96 versus 92 percent; P = 0.32), and influenza B (91 versus 80 percent; P = 0.030) strains. Both standard- and high-dose vaccines were well tolerated, with the most frequent adverse events being myalgia (19 percent), malaise (14 percent), and local pain (10 percent).

"The implications of this research are important for future vaccination efforts in the HIV-positive population," the authors write. "This study suggests that a substantial number of HIV-infected patients may not be obtaining sufficient protection with the standard influenza vaccine."

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Journal reference: Annals of Internal Medicine

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