Improving HIV Case Finding Through Index Testing: Findings from Health Facilities in 12 Districts of South Africa, October 2019–September 2021

To assess the importance of index testing in HIV case finding, we analyzed quarterly data from October 2019 to September 2021 from 371 facilities in 12 districts in South Africa. Index testing accounted for 2.6% of all HIV tests (index and non-index) (n = 163,633), but 17.8% of all HIV-positive results, with an HIV-positivity 4-times higher than non-index testing modalities (4.1%). Despite twice as many adult females ≥ 15 years accepting index testing (n = 206,715) compared to adult males ≥ 15 years (n = 102,180), females identified fewer contacts (n = 91,123) than males (n = 113,939). Slightly more than half (51.2%) of all contacts elicited were tested (n = 163,633/319,680), while 19.7% (n = 62,978) of elicited contacts were previously diagnosed as HIV-positive and not eligible for further testing. These findings indicate index testing can be effective in increasing HIV diagnoses in South Africa. Further operational research is needed to address gaps identified in the index testing cascade, including elicitation and testing of contacts.