Implementation of Option B and a fixed-dose combination antiretroviral regimen for prevention of mother-to-child transmission of HIV in South Africa: A model of uptake and adherence to care.

INTRODUCTION: Initiating and retaining pregnant women on antiretroviral therapy (ART) to prevent mother-to-child HIV transmission (PMTCT) remains a major challenge facing African HIV programs, particularly during the critical final months prior to delivery. In 2013, South Africa implemented its "Option B" PMTCT regimen (three-drug ART throughout pregnancy and breastfeeding, regardless of maternal CD4 count) and introduced once-daily fixed-dose combinations and lifelong ART. Currently, the uptake of Option B and its possible impact on adherence to PMTCT during the critical final months of pregnancy is unclear. MATERIALS AND METHODS: We prospectively collected visit data from a cohort of adult, HIV-infected, pregnant women between July 2013-August 2014 to estimate three models of adherence to PMTCT during the final 16 weeks immediately preceding delivery. Adherence was defined according to possession of antiretroviral drugs, which was inferred from clinic visit records under varying assumptions in each model. We describe uptake of the PMTCT regimen, gestational age at initiation, and model possible scenarios of adherence through delivery after the implementation of Option B. RESULTS: Among 138 women enrolled (median (IQR) age 28 years (24-32), median CD4 count 378 cells/mm3), median (IQR) gestational age at initiation was 22 weeks (16-26). Estimates of adherence during the final 16 weeks of pregnancy prior to delivery ranged from 75% (52-89%) under the best case scenario assumptions to 52% (30-75%) under the worst case scenario assumptions. Estimates of the proportion of women who would achieve 80% adherence to PMTCT were <50% across all models. CONCLUSIONS: Despite the switch to Option B and once-daily dosing, South African women continue to initiate PMTCT late in pregnancy, and estimations of regimen adherence, as modelled using PMTCT visit attendance data, is poor, with <50% of women reaching 80% adherence during final months of pregnancy across all models. Further guideline changes and interventions are needed to achieve vertical transmission goals. TRIAL REGISTRATION: ClinicalTrials.gov NCT01710397 South African National Clinical Trials Register DOH-27-0213-4177.

Understanding Predictors of Early Antenatal Care Initiation in Relationship to Timing of HIV Diagnosis in South Africa.

Effective prevention of mother-to-child transmission benefits from early presentation to antenatal care (ANC). It is, however, unclear whether a previous HIV diagnosis results in earlier initiation of ANC. We estimated the probability of early ANC initiation among women with a previous HIV-positive diagnosis compared to those who first tested for HIV during ANC and explored determinants of early ANC among HIV-positive women. We conducted an analysis of a cross-sectional survey among 411 HIV-positive adult (>18 years) women who gave birth at midwife obstetrics units in Gauteng between October 2016 and May 2017. Predictors of early ANC (defined as initiating ANC before or at 14 weeks of gestation) were assessed by multivariate log-binomial regression model. Overall, 51% (210) were diagnosed during pregnancy with 89% (188) initiating antiretroviral therapy on the same day of diagnosis. There was no meaningful difference in the timing of ANC initiation between women with previous HIV diagnosis [adjusted risk ratio (aRR) = 1.2; 95% confidence interval (95% CI): 0.9-1.7] compared with those diagnosed during pregnancy. Early ANC was predicted by planned pregnancy [aRR = 1.3; 95% CI: 1.1-1.7], parity (>2 children) [aRR = 0.6; 95% CI: 0.2-0.9] compared to not having a child, and tuberculosis diagnosis [aRR = 2.9; 95% CI: 1.4-6.1]. Our results suggest the need for a targeted intervention among HIV-positive women by improving the quality, content and outreach of ANC services to enhance early ANC uptake, and minimize mother-to-child transmission risk.