Unique HIV Risk Factors and Prevention Needs for Transgender Women and Cisgender Men Who Have Sex with Men in Bangkok, Thailand.

Background: Transgender women (TGW) and cisgender men who have sex with men (cis-MSM) are often grouped together as key populations. We evaluated behavioral and other characteristics that may distinguish TGW from cis-MSM in Bangkok, Thailand. Methods: We enrolled into an 18-month cohort cis-MSM and TGW 18-35 years of age without HIV, who reported anal intercourse plus condomless anal intercourse, multiple partners, transactional sex, and/or sexually transmitted infection. Robust multivariable Poisson regression was used to estimate adjusted prevalence ratios (aPRs) and confidence intervals (95% CIs) for associations with being a TGW. Among TGW, logistic regression with generalized estimating equations was used to estimate adjusted odds ratios (aORs) and 95% CIs for associations with taking hormones and having undergone gender affirmation surgery (GAS). Results: From 2017 to 2019, 660 cis-MSM and 348 TGW were enrolled. Compared to cis-MSM, TGW were more likely to be attracted to mostly/only men (aPR: 3.79, 95% CI: 1.57-9.13), have a higher monthly income (aPR: 1.25, 95% CI: 1.04-1.50), have lived in their current residence for <1 year (aPR: 1.21, 95% CI: 1.01-1.46), have engaged in sex work (aPR: 1.48, 95% CI: 1.23-1.77), and be less likely to have ever undergone HIV testing (aPR: 0.83, 95% CI: 0.70-0.98). Among TGW, 149 (42.8%) were taking hormones and 33 (9.5%) had undergone GAS. GAS was more common among TGW who ever used methamphetamines (aOR: 1.55, 95% CI: 1.00-2.41) and those >23 years (18-20-year olds aOR: 0.17, 95% CI: 0.05-0.55; 21-23-year olds aOR: 0.36, 95% CI: 0.20-0.65). Conclusions: TGW and cis-MSM are unique populations; tailored, gender-affirming, differentiated models of HIV prevention and care are necessary to address vulnerabilities specific to each key population.

Additional boosting to the RV144 vaccine regimen increased Fc-mediated effector function magnitude but not durability.

OBJECTIVES: The RV144 vaccine trial resulted in a decreased risk of HIV acquisition that was associated with a nonneutralizing antibody response. The objective of this study was to determine the impact of an additional boost to the RV144 vaccine regimen on antibody effector function and durability. DESIGN: RV306 was a randomized, double-blind late boosting of the RV144 prime-boost regimen in HIV-uninfected Thai adults (NCT01931358). This analysis included study participants who received the RV144 vaccine regimen and received no additional boost (group 1) or were boosted with ALVAC-HIV and AIDSVAX (group 2) or only AIDSVAX alone (group 3) 24 weeks after completing the RV144 series. METHODS: Plasma samples from RV306 study participants were used to measure antibody-dependent cellular phagocytosis (ADCP), antibody-dependent neutrophil phagocytosis (ADNP), antibody-dependent complement deposition (ADCD), antibody-dependent cellular cytotoxicity (ADCC), trogocystosis, and gp120-specifc IgG subclasses. RESULTS: Additional boosting increased the magnitude of all Fc-mediated effector functions 2 weeks following the additional boost compared with 2 weeks after completing the RV144 regimen. However, only trogocytosis remained higher 24-26 weeks after the last vaccination for the study participants receiving an additional boost compared with those that did not receive an additional boost. The additional boost increased IgG1 and IgG4 but decreased IgG3 gp-120 specific antibodies compared with 2 weeks after completing the RV144 regimen. CONCLUSION: Additional boosting of RV144 improved the magnitude but not the durability of some Fc-mediated effector functions that were associated with vaccine efficacy, with trogocytosis being the most durable.

ALVAC-HIV and AIDSVAX B/E vaccination induce improved immune responses compared with AIDSVAX B/E vaccination alone.

The RV144 phase III vaccine trial demonstrated that ALVAC-HIV and AIDSVAX B/E administration over 6 months resulted in 31% efficacy in preventing HIV acquisition, while administration of AIDSVAX B/E alone in both VAX003 and VAX004 studies failed to show efficacy. In this study, we aimed to understand the impact of ALVAC-HIV on the development of cellular, humoral, and functional immune responses compared to the administration of AIDSVAX B/E alone. ALVAC-HIV in combination with 3 doses of AIDSVAX B/E significantly increased CD4+ HIV-specific T cell responses, polyfunctionality, and proliferation compared with 3 doses of AIDSVAX B/E alone. Additionally, Env-specific plasmablasts and A244-specific memory B cells were identified with a significantly higher magnitude in the group that received ALVAC-HIV. Subsequently, data revealed increased magnitude of plasma IgG binding to and avidity for HIV Env in participants who received ALVAC-HIV compared with 3 doses of AIDSVAX B/E alone. Lastly, levels of the Fc-mediated effector functions antibody-dependent cellular cytotoxicity, NK cell activation, and trogocytosis were significantly increased in participants who received ALVAC-HIV compared with those receiving AIDSVAX B/E alone. Taken together, these results suggest that ALVAC-HIV plays an essential role in developing cellular and humoral immune responses to protein-boosted regimens relative to protein alone.