Background:  HIV-infected persons have a reduced response to hepatitis B virus (HBV) vaccine, especially those with low CD4 counts. Intradermal administration of HBV vaccine, which results in antigen processing by Langerhans cells in the dermis, has been successful in health care workers and dialysis patients who failed to respond to administration of the vaccine by the intramuscular route.

Methods:  We administered recombinant HBV vaccine (Merck) 0.25 mL intradermally every 2 weeks x 4 and repeated this series for those with anti-HBs <30 mIU/mL (“low titer” anti-HBs) in HIV-infected patients who failed to develop anti-HBs in response to 2 series of 3 doses of HBV vaccine administered intramuscularly. We followed responding subjects (anti-HBs >10 mIU/mL) for 12 months to assess the durability of the anti-HBs response. All subjects were negative for both HBsAg and anti-HBc.

Results:  We enrolled 11 subjects (8 male) with a median CD4 count of 410. After 4 intradermal doses, 5 (45%) developed anti-HBs. Of the 8 who received a second series of 4 intradermal doses, 6 failed to respond to the first series and 2 who had low-titer anti-HBs (11.9 and 27.6 mIU/mL). None of the 6 patients who failed to respond to 4 intradermal doses developed anti-HBs after 8 intradermal doses. Of the 2 subjects with low-titer anti-HBs after 1 series of 4 intradermal doses, 1 was anti-HBs-negative after the second intradermal series and the other subject’s anti-HBs titer dropped from 27.6 to 15.7 mIU/mL and then was negative at 6 and 12 months later. Of the 3 subjects with high-titer anti-HBs after 4 intradermal doses, 1 with an initial anti-HBs titer of 61.8 mIU/mL moved to another province before 6 months of follow-up, 1 with anti-HBs of 79.9 mIU/mL dropped to 12.5 mIU/mL at 6 months and became anti-HBs negative at 12 months, and the 1 with an initial anti-HBs of 110 mIU/mL dropped to 22.3 mIU/mL at 6 months and has not yet reached 12 months of follow-up.

Conclusions:  In HIV-infected subjects who fail to respond to 2 series of recombinant HBV vaccine administered intramuscularly, the administration of HBV vaccine intradermally results in an initial anti-HBs response in about half, but this response wanes within 1 year.