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HIV+ Less Likely to Respond to Hepatitis B Vaccine, but More Shots Increase Protection

Adults in Kenya responded as well overall to hepatitis B vaccination as people in high-income countries. People with HIV had poorer response, but this could be mostly overcome with repeated doses, according to a study described in the February 1, 2013, Journal of Infectious Diseases.

Research in industrialized countries such as the U.S. has found that HIV positive people as a group do not respond as well to hepatitis B virus (HBV) vaccines as HIV negative people. But this has not been well studied in resource-limited settings.

Elizabeth Irungu, Jared Baeten and colleagues from the University of Washington in Seattle, Kenyatta National Hospital, and Jomo Kenyatta University  compared immune responses to HBV vaccination among Kenyan adults with and without HIV-1 infection. They also looked at response to re-vaccination among HIV positive participants.

The study included 603 participants in the groundbreaking Partners PrEP HIV prevention trial who were tested and found to be susceptible to HBV (that is, not previously vaccinated or infected). Just over half were HIV positive, and within this group the median CD4 T-cell count was 557 cells/mm³, indicating well-preserved immune function. None were receiving antiretroviral therapy (ART), in accordance with country treatment guidelines in effect at the time.

Results

• HIV positive participants were significantly less likely to develop protective hepatitis B surface antibody titers after the first HBV vaccine series compared with HIV negative people
• Initial non-response rates for HIV positive and HIV negative people were 35.8% vs 14.3%, respectively.
• However, 86.3% of the HIV positive initial non-responders who received further vaccine doses (88 of 102) responded to re-vaccination.
• 72 people developed adequate antibody titers after 1 additional dose and 16 did so after 3 additional doses.
• Altogether, the overall response rate for HIV positive participants reached 94.9%.
• Among the HIV positive participants, lower CD4 cell count (< 500 cells/mm³) and male sex were independent predictors of non-response to initial vaccination in a multivariate analysis.
• Lower body mass index, higher HIV viral load (> 50,000 copies/mL), and longer time between initial and follow-up vaccination predicted non-response to re-vaccination.

Based on these findings, the researchers concluded, "Kenyan adults had similar HBV vaccination responses as persons from high-income countries. Timely revaccination of HIV-1-infected non-responders increased response to the vaccine to 95%."

2/15/13

Reference

E Irungu, N Mugo, K Ngure, JM Baeten, et al. Immune Response to Hepatitis B Vaccination Among HIV-1 Infected and Uninfected Adults in Kenya. Journal of Infectious Diseases 207(3):402-410. February 1, 2013.