HIV / STI
HIV Transmission in a Declining African Epidemic: A Matched Case-Control and Contact-Tracing Study Griffin Bell* Griffin Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Bell Johns Hopkins University
HIV incidence is declining throughout Africa. The dynamics of residual transmission in waning epidemics remain unclear, complicating allocation of novel prevention modalities such as long-acting pre-exposure prophylaxis.
We identified persons with incident HIV (cases) from a longitudinal population surveillance cohort in Uganda experiencing declining incidence. Cases were individually matched to persons without HIV (controls). Sexual partners were elicited, traced, and enrolled in both groups. Female sex workers (FSW) were enrolled from named venues of untraceable FSW partners. We used conditional logistic regression, transmission modeling, and phylogenetics to identify characteristics of incident case networks.
We administered 37,392 HIV tests to 27,013 people, identifying 4,653 people with HIV and 180 people with an incident HIV infection. We enrolled 164 (91%) of those with an incident HIV infection, including 79 (48%) men. Male cases reported more partners (mean=3.8) than male controls (2.2), female cases (1.9), and female controls (1.2). FSW partnerships were common among male cases (43%) and were associated with a 15.5-fold (95% CI: 3.7-64.8) increase in the odds of incident infection. The number of reported female non-SW partners was not significantly associated with incident infection in men. Most male cases with FSW partners also had female non-SW partners (91%), and female non-SW partners of cases had higher HIV seroprevalence (59.5% vs 33.7%) and population prevalence of viremia (15.0% vs 3.4%) than venue-enrolled FSWs, but transmission modeling still attributed 29.8% of all male incident infections to sex with FSWs. PrEP use among HIV-negative partners of cases was uncommon (5.4%).
Increased prioritization of male clients of FSWs in HIV programs in Africa, including for long-acting injectable PrEP, could be a highly efficient and effective strategy for HIV prevention and epidemic control.