Polytopic fractional delivery of an HIV vaccine alters cellular responses and results in increased epitope breadth in a phase 1 randomized trial.

BACKGROUND: Elicitation of broad immune responses is understood to be required for an efficacious preventative HIV vaccine. This Phase 1 randomized controlled trial evaluated whether administration of vaccine antigens separated at multiple injection sites vs combined, fractional delivery at multiple sites affected T-cell breadth compared to standard, single site vaccination. METHODS: We randomized 90 participants to receive recombinant adenovirus 5 (rAd5) vector with HIV inserts gag, pol and env via three different strategies. The Standard group received vaccine at a single anatomic site (n = 30) compared to two polytopic (multisite) vaccination groups: Separated (n = 30), where antigens were separately administered to four anatomical sites, and Fractioned (n = 30), where fractions of each vaccine component were combined and administered at four sites. All groups received the same total dose of vaccine. FINDINGS: CD8 T-cell response rates and magnitudes were significantly higher in the Fractioned group than Standard for several antigen pools tested. CD4 T-cell response magnitudes to Pol were higher in the Separated than Standard group. T-cell epitope mapping demonstrated greatest breadth in the Fractioned group (median 8.0 vs 2.5 for Standard, Wilcoxon p = 0.03; not significant after multiplicity adjustment for co-primary endpoints). IgG binding antibody response rates to Env were higher in the Standard and Fractioned groups vs Separated group. INTERPRETATION: This study shows that the number of anatomic sites for which a vaccine is delivered and distribution of its antigenic components influences immune responses in humans. FUNDING: National Institute of Allergy and Infectious Diseases, NIH.

Brief Report: A Panel Management and Patient Navigation Intervention Is Associated With Earlier PrEP Initiation in a Safety-Net Primary Care Health System.

BACKGROUND: Timely pre-exposure prophylaxis (PrEP) initiation is critical in at-risk populations, given that HIV acquisition risk persists during delays. Time to treatment initiation, a key metric in HIV care, has not been explored among PrEP users. Interventions that reduce time to PrEP initiation could prevent HIV infections. SETTING: Individuals initiating PrEP in a large primary care health network of 15 clinics, the San Francisco Primary Care Clinics (SFPCC), from July 2012 to July 2017 (N = 411). METHODS: We examined factors associated with time from first PrEP discussion with a provider to PrEP initiation date using an adjusted Cox proportional-hazards model, with hazard ratios (HRs) >1 indicating earlier initiation. We also examined the relationship between delayed PrEP initiation and PrEP persistence (staying on PrEP) in an adjusted Cox proportional-hazards model. RESULTS: PrEP users initiated PrEP after a median of only 7 days. However, there were notable outliers, with 29% waiting >30 days and 12% waiting >90 days. In an adjusted proportional-hazards model, a panel management and patient navigation intervention was associated with earlier PrEP initiation [HR: 1.5; 95% confidence interval (CI): 1.1 to 2.0], whereas only other race/ethnicity compared with white race was associated with delayed PrEP initiation (HR: 0.7; 95% CI: 0.5 to 1.0). Delayed PrEP initiation >30 days was associated with shorter PrEP persistence in an adjusted proportional-hazards model (HR: 1.3; 95% CI: 1.0 to 1.7). CONCLUSIONS: PrEP initiation within a week is feasible in a primary care safety-net health system. Setting a goal of rapid PrEP initiation, with the support of panel management and patient navigation, could address delays in at-risk groups.

Analysis of HIV Diversity in HIV-Infected Black Men Who Have Sex with Men (HPTN 061).

BACKGROUND: HIV populations often diversify in response to selective pressures, such as the immune response and antiretroviral drug use. We analyzed HIV diversity in Black men who have sex with men who were enrolled in the HIV Prevention Trials Network 061 study. METHODS: A high resolution melting (HRM) diversity assay was used to measure diversity in six regions of the HIV genome: two in gag, one in pol, and three in env. HIV diversity was analyzed for 146 men who were HIV infected at study enrollment, including three with acute infection and 13 with recent infection (identified using a multi-assay algorithm), and for 21 men who seroconverted during the study. HIV diversification was analyzed in a paired analysis for 62 HIV-infected men using plasma samples from the enrollment and 12-month (end of study) visits. RESULTS: Men with acute or recent infection at enrollment and seroconverters had lower median HRM scores (lower HIV diversity) than men with non-recent infection in all six regions analyzed. In univariate analyses, younger age, higher CD4 cell count, and HIV drug resistance were associated with lower median HRM scores in multiple regions; ARV drug detection was marginally associated with lower diversity in the pol region. In multivariate analysis, acute or recent infection (all six regions) and HIV drug resistance (both gag regions) were associated with lower median HRM scores. Diversification in the pol region over 12 months was greater for men with acute or recent infection, higher CD4 cell count, and lower HIV viral load at study enrollment. CONCLUSIONS: HIV diversity was significantly associated with duration of HIV infection, and lower gag diversity was observed in men who had HIV drug resistance. HIV pol diversification was more pronounced in men with acute or recent infection, higher CD4 cell count, and lower HIV viral load.

Sexually transmitted infections and pre-exposure prophylaxis: challenges and opportunities among men who have sex with men in the US.

Pre-Exposure Prophylaxis (PrEP) has shown high efficacy in preventing human immunodeficiency virus (HIV) infection among men who have sex with men (MSM) in several large clinical trials, and more recently in "real world" reports of clinical implementation and a PrEP demonstration project. Those studies also demonstrated high bacterial sexually transmitted infection (STI) incidence and raised the discussion of how PrEP may impact STI control efforts, especially in the setting of increasing Neisseria gonorrhoeae antimicrobial resistance and the increase in syphilis cases among MSM. Here, we discuss STIs as a driver of HIV transmission risk among MSM, and the potential opportunities and challenges for STI control afforded by expanded PrEP implementation among high-risk MSM.

Peer social support is associated with recent HIV testing among young black men who have sex with men.

Resiliency factors such as social support have been associated with more frequent HIV testing among MSM. We examined the association between social support and delayed HIV testing in the context of structural discrimination and individual factors among young Black MSM. We combined two independent cross-sectional samples recruited 1 year apart from a venue-based, modified time-location sampling study of young Black MSM aged 18-29 years in the US South. Our subsample (N = 813) was men who self-reported not being HIV positive and who indicated they had one or more male sex partners in the past 2 months. Using a social epidemiology framework we estimated associations of structural (racism and homophobia), social (social support from other Black MSM friends) and individual factors with delayed HIV testing (>6 months ago) using logistic regression. Bivariate analyses demonstrated that individual level variables as well as experiences of racism (OR 1.20, 95% CI 1.02-1.41) and homophobia (OR 1.49, 95 % CI 1.02-2.17) were associated with higher risk of delayed HIV testing. Receiving social support from other Black MSM friends was associated with lower risk of delayed HIV testing (OR 0.80, 95 % CI 0.67-0.95). In multivariable models, social support remained significantly associated with lower risk of delayed HIV testing after inclusion of structural and individual level variables. Social support has a positive and robust association with HIV testing among young Black MSM. Whether community building and development of resiliency factors can overcome structural, social, and individual-level barriers to HIV prevention and care for young Black MSM warrants further study.