Abstract
BACKGROUND: We compared antibody (Ab) responses to a quadrivalent (types 6, 11, 16, and 18) human papillomavirus (HPV) vaccine between men and women with HIV-1. METHODS: A retrospective analysis of participant-level data from published clinical trials of HPV vaccine administered at study entry and at weeks 8 and 24 was conducted separately for baseline Ab undetectable and baseline Ab detectable using Ab titers and titer changes from baseline, respectively, at week 28 and year 1.5. Generalized estimating equations accounted for multiple HPV types and were adjusted for multiple baseline factors, including existing HPV antibodies before vaccination from natural exposure. RESULTS: We evaluated 575 participants with CD4+ count >200 cells/mm3, 323 men and 252 women: median ages 46 and 38 years, respectively. Week 28 and year 1.5 Ab titers were similar between men and women regardless of the baseline Ab detection in multivariate models. HIV-1 RNA ≥400 copies/mm3 was associated with a lower week 28 Ab response; in baseline Ab detectable, the baseline HPV Ab titer level, HPV DNA detection, and lower CD4+/CD8+ ratio were also associated with a lower response. CD4+/CD8+ ratio was a stronger predictor in the year 1.5 Ab analysis than in the week 28 analysis. Ab responses among baseline Ab detectable were only somewhat higher than those among baseline Ab undetectable (eg, type 16 week 28 median 3.46 vs 3.20 log10 mMU/mL) despite the existing baseline titer (median 1.74). CONCLUSIONS: We did not find any sex differences of serologic response to HPV vaccine. Ab titer gain was lower in those with preexisting antibodies due to previous natural infection.