Background: The reported coverage of any antiretroviral (ARV) prophylaxis for prevention of mother-to-child transmission (PMTCT) has increased in sub-Saharan Africa in recent years, but was still only 60% in 2010. However, the coverage estimate is subject to overestimations since it only considers enrolment and not completion of the PMTCT programme. The PMTCT programme is complex as it builds on a cascade of sequential interventions that should take place to reduce mother-to-child transmission (MTCT) of HIV: starting with antenatal care (ANC), HIV testing, and ARVs for the woman and the baby.

Objective: The objective was to estimate the number of children infected with HIV in a district population, using empirical data on uptake of PMTCT components combined with data on MTCT rates.

Design: This study is based on a population-based cohort of pregnant women recruited in the Iganga-Mayuge Health and Demographic Surveillance Site in rural Uganda 2008–2010. We later modelled different scenarios assuming increased uptake of specific PMTCT components to estimate the impact on MTCT for each scenario.

Results: In this setting, HIV infections in children could be reduced by 28% by increasing HIV testing capacity at health facilities to ensure 100% testing among women seeking ANC. Providing ART to all women who received ARV prophylaxis would give an 18% MTCT reduction.

Conclusions: Our results highlight the urgency in scaling-up universal access to HIV testing at all ANC facilities, and the potential gains of early enrolment of all pregnant women on antiretroviral treatment for PMTCT. Further, to determine the effectiveness of PMTCT programmes in different settings, it is crucial to analyse at what stages of the PMTCT cascade that dropouts occur to target interventions accordingly.