AbstractBACKGROUND Young women aged 15–24 bear a disproportionate burden of new HIV infections in sub-Saharan Africa. Age-disparate relationships with older men have been proposed as a major contributor to this pattern. METHODS We conducted whole-genome sequencing of HIV in large cohort of individuals in KwaZulu-Natal, South Africa, (the Vukuzazi cohort). Samples with viral loads >50 copies/ml were sequenced. Genomes passing quality control were grouped into clusters using maximum-likelihood phylogenetic analysis. Potential transmission pairs were analysed alongside participant age and sex data. A Bayesian random-effects model estimated transmission rates between demographic groups while accounting for population age–sex structure. FINDINGS Among 18,025 participants enrolled 2018–2020, 6,096 were HIV-positive. Sequencing yielded 1,097 genomes, identifying 89 clusters containing 205 individuals and 73 likely male–female linked phylogenetic pairs. Across pairs, men were a median of 5 years older than women (IQR −1, 12). Women CONCLUSIONS Relative transmission rates were greatest with moderate age differences. Large intergenerational age gaps were not dominant.
Hartley et al. (Fri,) studied this question.