Combination antiretroviral treatment use in prevention of mother-to-child transmission programmes: 6-week HIV prevalence and relationship to time of antiretroviral treatment initiation and mixed feeding

BACKGROUND: In Zimbabwe, 16% of pregnant women aged 15–49 years are infected with HIV. More than 90% of HIV infection in children is through mother-to-child transmission (MTCT). We investigated the effectiveness of the Option B+ in reducing HIV infection and factors associated with HIV transmission among infants born to mothers enrolled in the prevention of mother-to-child transmission (PMTCT) programme. METHODS: We randomly selected 1204 early infant HIV diagnosis test results for HIV-exposed infants and linked these results to maternal clinical records at primary healthcare clinics in Harare to estimate the prevalence of MTCT and to determine the clinical factors associated with MTCT of HIV at 6 weeks. RESULTS: Of the 1204 infants in the study, 2.5% (95% confidence interval [CI], 1.7–3.5) were infected with HIV at 6 weeks post-delivery. Antiretroviral adherence reduced the odds of HIV infection by about 99% (odds ratio [OR] 0.01 [95% CI, 0.00–0.06]). Both mixed feeding (OR 3.89 [95% CI, 0.92–16.50]) and late initiation of antiretroviral treatment (ART) (after delivery) (OR 3.18 [95% CI, 0.42–23.94]) increased the odds of HIV infection. CONCLUSION: Early initiation of combination ART reduces 6-week MTCT of HIV in PMTCT programmes to levels similar to those found in controlled trial settings. Exclusive breastfeeding remains important even in the presence of ART.