Implementation of universal neonatal vaccination program against hepatitis B virus (HBV) has significantly reduced HBV seroprevalence in general population and people living with HIV (PLWH). Optimal strategy of revaccination remains unknown among people whose immunity has waned after neonatal vaccination. This randomized controlled trial investigated the serological responses to three standard- (20-?g) or double-dose (40-?g) HBV revaccination among HIV-positive and HIV-negative men who have sex with men (MSM).
MSM who were born after 1 July, 1986 and tested negative for HBsAg and anti-HBc with anti-HBs titer <10 mIU/ml were eligible for enrollment. Subjects who were aged <20 years or receiving chemotherapy or immunosuppressants within 30 days prior to screening were excluded. PLWH not on stable antiretroviral therapy were also excluded. Participants were randomized in a 1:1 ratio (stratified by CD4 count for PLWH) to receive three standard or double doses of HBV vaccine that were administered at Weeks 0, 4, and 24. Adverse events were recorded for severn days after each injection and serological responses were assessed at Weeks 28 and 48. Primary end point was serological response at Week 28 (defined as having anti-HBs titer ?10 mIU/ml) and secondary end points were high-titer response (anti-HBs ?100 mIU/ml) and adverse effects.
From September 2017 to September 2021, 243 (75%) HIV-positive MSM and 81 (25%) HIV-negative MSM with a mean age of 27.6 years were enrolled with 162 in each arm. The two groups were well balanced in terms of clinical characteristics. In PLWH, 70% had CD4 counts > 500 cells/mm3 and 95% were virally suppressed (HIV RNA load <50 copies/ml). The serological response rates at Week 28 were 95% and 88% for double-dose and standard-dose and double-dose group (p=0.04), respectively; and the respective high-titer response rate was 85% and 75% (p=0.05). At Week 48, the high-titer response rate for double-dose group was higher than that for standard-dose group (88% vs 61%, p=0.025). In multivariate logistic regression analysis (Table), double-dose HBV revaccination and baseline anti-HBs titer were significantly associated with serological response and high-titer response at Week 28 and 48.
Revaccination with three double doses of HBV vaccine results in higher serological responses than with three standard-doses of HBV vaccine among MSM who were born in the era of universal neonatal HBV vaccination.