Results of integrating recency testing into routine index testing services in Lusaka, Zambia: A mixed effects regression analysis

As countries move toward epidemic control, reaching PLHIV unaware of their status becomes increasingly difficult, necessitating targeted strategies like index testing. We evaluated a strategy incorporating identification of recent HIV acquisition into routine index testing in Zambia.

Consecutive adults newly diagnosed with HIV at two Lusaka health facilities were enrolled into a pilot interventional cohort to undergo rapid test for recent infection (RTRI) and viral load testing per the national recent infection testing algorithm (RITA). Consenting participants received RITA results; those with recent infection were offered additional partner elicitation, assisted partner notification, and contact tracing after routine index testing services. We compared test positivity between contacts of index participants with long-term versus recent HIV acquisition and used regression and latent class analyses to identify factors associated with recent acquisition.

Between May 2021-March 2022, we enrolled 321 of 393 (81.7%) newly diagnosed PLHIV and analyzed 317, with median age 31 years (IQR: 25-37) and most (63.1%) female. HIV positivity did not differ between contacts of RITA-recent (28.6%) versus long-term (27.9%) index participants (p = 0.942). Recency was strongly associated with condomless sex at last sex (PR: 7.25, 95% CI: 3.06-17.19), which latent class analysis confirmed was consistently associated with other high-risk behaviors. Of 305 participants completing a social harms survey, 27 (8.9%) reported ≥1 harm attributed to recency testing.

While integrating recency testing into routine index testing was feasible, our findings do not support its use to improve efficiency. Risk behavior assessment may help prioritize PLHIV for recency and index testing.