The ANRS 12249 Treatment as Prevention trial was a two-arm cluster randomised trial implemented in 22 communities in the Hlabisa sub-district in KwaZulu-Natal, South Africa.

The hypothesis was that HIV testing of all adult members of a community, followed by immediate ART initiation of all, or nearly all, HIV-infected participants regardless of immunological or clinical staging, would prevent onward transmission and reduce HIV incidence in this population.

HIV-positive individuals in the intervention arm were informed that they would be offered ART immediately, regardless of their CD4 count, to prevent transmission to their sexual partners. Those in the control arm were informed that ART would be provided according to national guidelines. Read more about the results here.

The trial started enrolment on 9 March 2012, and concluded on 30 June 2016. The full study protocol is available here.