HIV incidence and its associated factors among young adults with multiple sexual partners in Maputo, Mozambique: a vaccine preparedness study

Abstract

Introduction: Sub-Saharan Africa has a high burden of HIV, particularly among female sex workers (FSW) and men who have sex with men (MSM). Future clinical trials to evaluate vaccines and other interventions to prevent HIV will need to enroll populations with high HIV incidence. We conducted an observational study of HIV incidence among men and women with multiple sexual partners-including MSM and FSW-in Maputo, Mozambique, in order to prepare the country to conduct future efficacy trials of candidate HIV vaccines and other HIV prevention products.

Methods: We conducted a prospective observational HIV incidence study in Maputo, Mozambique, that enrolled adults aged 18-35 years, without HIV, who had two or more sexual partners in the preceding three months. Recruitment strategies prioritized participation of MSM and FSW. Participants were followed for 24 months with HIV-1 testing every 3 months and staff-administered behavioral questionnaires every 6 months. Cox proportional hazard modeling was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for factors potentially associated with HIV acquisition.

Results: From January 2014 to October 2017, 505 adults without HIV were enrolled with median age of 21 years (interquartile range:19-24); 41% were female and 82% were single. There were 19 HIV seroconversions (10 female and 9 male) during 943 person-years (PY) of observation (overall HIV incidence 2.02/100PY; 95%CI 1.21-3.15). The highest HIV incidence was observed among sex workers (2.08/100PY; 95%CI 0.25-7.52) and MSM (19.18/100PY; 95%CI 3.96-56.06). Increased hazard of incident HIV was observed among participants who were MSM (HR = 27.95, 95%CI 4.39-117.94), p = 0.0004), reported three or more sexual partners at enrollment (HR = 7.39, 95%CI 1.64-33.25, p = 0.009), and indicated ever having a sexual partner living with HIV (HR = 9.64, 95%CI 2.23-41.71, p = 0.002).

Conclusion: Our findings may inform inclusion criteria for upcoming clinical trials of HIV prevention interventions, including vaccine candidates, which may prioritize enrollment of MSM, people with more than three sexual partners, and people with sexual partners who are living with HIV. These same populations are in need of further intervention to reduce HIV incidence.

Keywords: Sexual behavior key populations; Acquired immunodeficiency syndrome; Africa South of the Sahara; Risk factors; Sexual and gender minorities.

Fig. 1

RV363 screening, enrollment, and follow-up flowchart. “Participant Decision” refers to those who terminated from the study by their own discretion due to pregnancy, inability to keep visits, perceived social harms, not interested to continue after acquiring HIV, and moving from the area

Fig. 2

HIV incidence rate by quartiled enrollment number and sex. Figure lines represent the trend in incidence across enrollment quartiles. Shaded regions depict the confidence intervals for incidence given cumulated incidence and person-time

Fig. 3

HIV incidence by quartiled enrollment number and age. Figure lines represent the trend in incidence across enrollment quartiles. Shaded regions depict the confidence intervals for incidence given cumulated incidence and person-time

Fig. 4

Kaplan-Meier survival curves for incident HIV. Figure A-D represent the univariable Kaplan Meier curve for proportional hazard of HIV for a given covariate across the observation time. A depicts the participant reporting having had a PLWH in the prior 3 months; (B) depicts hazard associated with having a secondary sexual partner; (C) depicts hazard associated with partner diad; (D) depicts associated hazard with number of sexual partners in the prior 3 months