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MSM with, without HIV similarly affected during 2009 H1N1 pandemic
During the 2009 influenza A(H1N1) pandemic in Bangkok, Thailand, rates of seroconversion to the virus were similar among men who have sex with men with HIV and those without HIV, according to recent findings.
Overall, seroconversion occurred in roughly one third of the study population, the researchers wrote.
In the study, researchers evaluated 368 MSM who were enrolled in the Bangkok Men’s Cohort study, an ongoing analysis of HIV prevalence. Of these, 157 were HIV-positive and 211 were HIV-negative. Participants were enrolled in the study since 2006. Blood samples were taken from these participants at baseline and every 4 months for those with HIV infection, and yearly for those without HIV.
For each participant, paired samples, both from before and after the 2009 H1N1 influenza pandemic, were taken and analyzed. Hemagglutination inhibition or microneutralization tests were used to test the samples for antibody response to specific influenza strains. Seroconversion to A(H1N1)pdm09 was defined as a 4-fold or higher increase in hemagglutination inhibition or microneutralization antibody titers and a minimum titer of 40 on the second sample. The researchers calculated the percentage of seroconversions among HIV-infected and HIV-uninfected individuals after the first two waves or after the third wave of the influenza pandemic. Those with available specimens from all three time periods were identified for both analyses. At the time of the serum sample collection, the median age of both HIV-infected and uninfected men was 28 years.
The researchers found that 28% of the participants seroconverted after the first year, and 35% seroconverted after year 2 of A(H1N1)pdm09 activity. Moreover, there was no difference in A (H1N1)pdm09 seroconversion between MSM with HIV (35%) and MSM without HIV (34%; P=.78).
According to the researchers, the relative youth and health of the MSM with HIV in this sample may have rendered them less vulnerable to A(H1N1)pdm09 .
“While infection did not appear to increase the probability of A(H1N1)pdm09 seroconversion, the majority of HIV-infected MSM in this study were young and had relatively preserved immune function,” the researchers wrote. “It remains unclear whether severely immunocompromised HIV-infected persons are more susceptible to A(H1N1)pdm09 influenza virus and to seasonal influenza viruses in general.”
Disclosure: The researchers report no relevant disclosures.