Fig. 4

Mean and 90% credible interval of annual proportion of new infections transmitted and acquired by people living with HIV (PLHIV) stratified by age group (A) and sexual partnering level (B). Most new infections were transmitted and acquired by PLHIV aged 25–34 years between 1990 and 2017, and men aged 35–44 thereafter. With respect to sexual partnering level, through the epidemic, the majority of infections were transmitted by those with more than 10 partners per year