BACKGROUND We compared antibody (Ab) responses to a quadrivalent (types 6,11,16,18) HPV vaccine between males and females with HIV-1. METHODS A retrospective analysis of participant-level data from published clinical trials of HPV vaccine administered at study entry, 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 adjusted for multiple baseline factors, including existing HPV antibodies prior to vaccination from natural exposure. RESULTS We evaluated 575 participants with CD4+ count >200 cells/mm3, 323 males and 252 females: median ages 46 and 38 years, respectively. Week 28 and Year 1.5 Ab titers were similar between males and females regardless of baseline Ab detection in multivariate models. HIV-1 RNA ≥400 copies/mm3 was associated with lower Week 28 Ab response; in Baseline Ab Detectable, baseline HPV Ab titer level, HPV DNA detection and lower CD4+/CD8+ ratio were also associated with lower response. CD4+/CD8+ 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 among Baseline Ab Undetectable (e.g. type 16 Week 28 median 3.46 vs. 3.20 log10 mMU/mL), despite existing baseline titer (median 1.74). CONCLUSION 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 prior natural infection.
Effects of Sex, Existing Antibodies, and HIV-1 Related and Other Baseline Factors on Antibody Responses to Quadrivalent HPV Vaccine in Persons with HIV.