Background: HPTN 071 (PopART) was a community randomized trial to measure the impact of offering a combined HIV-prevention package on the incidence of HIV. The HIV-prevention package included HIV-testing and was offered door-to-door (universal testing or UT) from January 2014 to December 2017.
Index testing (IT) aims to test sexual partners of patients registered at the HIV-clinic. We used data collected during the UT approach to estimate the potential impact of IT on knowledge of HV-positive status.
Methods: UT was offered in 8 intervention communities in Zambia in 3 consecutive annual rounds. During one annual round, all households in the community were visited at least once, all household members were enumerated and HIV-testing was offered to everyone. Re-visits were used to offer the intervention to household members that were absent at earlier visits. To estimate IT we defined an index case as a participant who self-reported being HIV-positive before testing was offered. We estimated IT by restricting data to household members of an index case. We compared acceptance and results of HIV-testing between this simulated IT approach and UT.
Results: In annual round 1, the HIV-positivity rate was higher under IT (1,304/10,679, 12.2%) than under UT (9,196/126,208, 7.3%) and decreased for both IT and UT with higher testing coverage in annual round 2 and 3.
Compared to UT, IT would reduce the number of tests required by approximately 90%. However, over 80% of the HIV-positives diagnosed under UT would remain undiagnosed under IT. IT only identifies 14.2% (1,304/9,196) of HIV-positives found under UT in annual round 1, increasing to 17%-18% over subsequent rounds.
Among participants of the intervention, IT would have resulted in 61.6% of the HIV-positives knowing their status (UNAIDS “first 90”) increasing to 83.6% if IT would have been done following 2 rounds of UT. UT identified 88.6% of HIV-positives in the first round, increasing to 96.7% after 3 rounds of UT.
Conclusions: Our data suggests index testing alone would be insufficient to reach UNAIDS “first 90” target and that a combination of strategies need to be deployed to increase coverage of the knowledge of HIV-positive status.