# Individual and population-level risk factors for new HIV infections among adults in Eastern and Southern Africa

## TL;DR

This study identifies individual and community-level factors that increase the risk of new HIV infections in Eastern and Southern Africa.

## Contribution

The study harmonizes data from multiple population-based cohorts to reveal shared and sex-specific risk factors for HIV acquisition.

## Key findings

- Untreated HIV prevalence in the community is a risk factor for both men and women across all ages.
- Partner acquisition rates in communities are linked to higher HIV incidence among 25-49-year-olds.
- Risk factors vary by age, sex, and study location, suggesting tailored prevention strategies could be effective.

## Abstract

Despite substantial recent declines, general population HIV incidence in sub-Saharan Africa remains above international targets. Better description of risk factors for new infections would improve prioritisation of interventions. Using data from population-based cohorts in Kenya, Malawi, Tanzania, South Africa, Uganda, Zimbabwe we described the prevalence of risk factors for men and women aged 15-24 and 25-49 and estimated the association between individual and community-level risk factors and HIV acquisition between 2005 and 2016. Among 43,434 men and 55,919 women aged 15 to 49 there were 4,612 seroconversions. Education, marital status, male circumcision, new sexual partners, types of partner, prevalence of untreated HIV infection in the community and community partner acquisition rates were associated with HIV incidence. Only the prevalence of untreated HIV was a risk for both sexes and apparent at all ages. The prevalence of risk factors varied by age, sex and study. HIV incidence was higher in people aged 25-49 living in communities where men had high partner acquisition rates. Our results show potential for improved prevention through changed timing of prevention interventions relative to behaviour and the utility of using community characteristics to target prevention.

The majority of incident HIV infections in Eastern and Southern Africa occur in the general population. Here, the authors harmonise data from eight open population-based cohort studies from six countries and describe individual and community-level risk factors for HIV acquisition.