Household survey of HIV incidence in Rwanda: a national observational cohort study

BACKGROUND:
In Rwanda, HIV prevalence among adults aged 15-49 years has been stable at 3% since 2005. The aim of this study was to characterise HIV incidence across Rwanda.
METHODS:
We did a nationally representative, prospective HIV incidence survey for the period of 2013-14, which used two-stage sampling. We randomly selected 492 villages in the first sampling stage and 14 households per village in the second stage. Participants completed a questionnaire and 14 140 people were tested for HIV. 13 728 participants were HIV negative, and were enrolled in the incidence cohort. Participants were retested and surveyed again after 12 months. Weights were calculated as the inverse of the probability to select the villages and the households.
FINDINGS:
The study period was from Nov 5, 2013, to Nov 15, 2014. Among 14 222 respondents from 6792 households, 14 140 were tested for HIV and 13 728 were HIV negative. Of 12 593 people who participated in the endpoint data collection activities, 5965 (47·4%) were men and the mean age was 30 years (SD 10·8). 11 237 (89·2%) participants lived in rural areas, 4826 (38·3%) were single, and 7140 (56·7%) were married or cohabitating. During the year, 35 participants had seroconversion, including 13 men and 22 women, resulting in an overall incidence of 0·27 per 100 person-years (95% CI 0·18-0·35). Incidence was 0·21 per 100 person-years (0·10-0·32) in men and 0·32 per 100 person-years (0·19-0·45) in women. Our findings suggested multiple breakouts, with multiple seroconversions occurring in three villages and two households. Incidence was higher in adults aged 36-45 years (0·37 per 100 person-years, 0·12-0·62; adjusted hazard ratio [aHR] 4·49, 95% CI 1·30-14·70) relative to those aged 16-25, higher in western province (0·57 per 100 person-years, 0·31-0·87; aHR 5·90, 1·33-25·28) relative to the northern province, and higher in urban areas (0·65 per 100 person-years, 0·23-1·07; aHR 3·10, 1·28-6·99) than in rural areas.
INTERPRETATION:
The incidence of HIV in Rwanda was higher than that previously estimated from models, with outbreaks seeming to contribute to the ongoing epidemic. Characterisation of incident infections can help the national HIV programmes to plan for preventive interventions tailored to the most at risk populations.
FUNDING:
Global Fund to Fight HIV, Tuberculosis and Malaria, WHO Rwanda, UNAIDS Rwanda, and the Government of Rwanda.