The key role of the youth in ongoing HIV-transmission: a community-based survey in KwaZulu-Natal, South Africa

New HIV infections among adults have decreased in the last ten years in high HIV prevalent countries. However, some groups of the population remain at high risk of HIV infection. We assessed the relation between sexual behavior, HIV awareness, antiretroviral therapy (ART) intake and viral suppression, and the age-gender groups the most at risk of maintaining HIV transmission in KwaZulu-Natal, South Africa. We performed an analysis, using data from participants aged 15–59 years of a population-based survey conducted in 2018. In total, 862 HIV-positive individuals were included, 10.1% were unaware of their HIV status, 15.8% not on ART and 16.3% virally unsuppressed. Overall, 10.6% had a high or very high risk of sexually transmitting HIV. Of them, 42.0% were women aged 20–34 years and 39.8% men aged 20–59 years, 50.0% were unaware of their status and 76.1% not on ART. Of the 2.3% individuals at very high risk of transmission, 68.4% were men aged 20–59 years. Efforts to increase HIV diagnosis, to detect early ART treatment failure, to provide enhanced adherence support and second- or third-line ART, as well as to promote behavioral-risk reduction interventions, are needed to reduce the pool of individuals at high risk of transmitting HIV.