Adults in Kenya had similar responses to hepatitis B virus vaccination as those from high-income countries, recent data indicate.
Although vaccine nonresponse was higher among participants with HIV, revaccination of the nonresponders increased the response to 95%, researchers reported in the Journal of Infectious Diseases.
“These results were very reassuring, as standard HBV vaccine demonstrated high response rates in African adults with and without HIV,” Jared Baeten, MD, PhD, associate professor of global health at the University of Washington School of Public Health, told Infectious Disease News. “People with HIV infection are known to have lower HBV vaccine response rates, but these data show that repeat vaccination with a standard vaccine series can achieve very high response rates in people with HIV, comparable to those without HIV.”
The prospective interventional study included 603 participants, of whom 310 had HIV. All of the participants were concurrently enrolled in the Partners PrEP study and were screened for HBV. Those who were susceptible to the disease were given the HBV vaccine regimen.
Six months after vaccination, 111 of the patients (35.8%) with HIV did not have protective HBV surface antibody titers vs. 42 of the 293 patients (14.3%) without HIV. In a multivariate analysis of the participants with HIV, sex and CD4 counts were associated with nonresponse. Men were more likely to be nonresponders as were participants who had CD4 counts of less than 500 cells/mcL.
Among the nonresponders with HIV, 102 completed the revaccination, of whom 72 developed a positive antibody response after the first dose and another 16 developed an antibody response after the third dose. Among those with HIV, the cumulative response was 64.2% after the initial series, 89% after the first revaccination dose and 94.9% after the complete revaccination series. Factors associated with nonresponse after revaccination included low BMI, a HIV-1 RNA of more than 50,000 copies/mL at baseline and a longer time to revaccination.
“These data emphasize that HBV vaccination generates high response rates in Africa and repeat vaccination in people with HIV appears to be a successful strategy,” Baeten said. “New questions to consider include the best initial vaccine schedule for people with HIV and the biologic mechanisms of non-response to vaccine.”