(220) The Utility and Versatility of Linked Database in HIV Care for tracking Vertical Transmission of HIV in the Western Cape Province in South Africa
Director, Epidemiology & Real World Evidence ViiV Healthcare, United States
Background: Assessment of real-world effectiveness of HIV vertical transmission (VT) prevention programs is essential to monitor progress towards VT elimination. However, robust assessment is challenging as it requires linked maternal-infant data and relatively complete follow-up and HIV testing during pregnancy and breastfeeding of mothers and infants.
Objectives: To demonstrate how Western Cape Provincial Health Data Centre (WCPHDC) in South Africa can track VTP.
Methods: Setting: The Western Cape has a high HIV burden with about 586,425 people living with HIV (PLWH) and 19% antenatal HIV prevalence. About 97% of mothers attend antenatal care and more than 95% deliver in health facilities.
Design: The Western Cape Department of Health developed the WCPHDC which links patient data across public sector systems and information domains. Unique health identifiers, with maternal-infant data linkage, are linked to electronic antiretroviral treatment (ART) program data and other datasets, allowing ascertainment of pregnancy, ART exposure, laboratory values (including maternal and infant HIV viral load, CD4 counts and infant HIV-PCR results), vital status and other outcomes. The WCPHDC funding model allows for external funding to support technical and analytic capacity. External funders with shared interests can collaborate in focus areas but have no access to WCPHDC data. Exposures, outcomes and analysis: Using algorithmic inference, WCPHDC identifies health conditions such as HIV and pregnancy and creates virtual observational cohorts using care, treatment and outcome data. This analysis describes a cohort of pregnant PLWH and their linked infants, with VT outcomes. Additionally, the WCPHDC identifies infants in real time with breastfeeding-acquired HIV who are at risk of acquired resistance.
Results: From April 2019 to March 2020, 18% of live births were identified by WCPHDC as HIV-exposed antenatally (17,063 pregnancies), of which 90% were exposed to ART during pregnancy. Of known HIV-exposed infants, 89% (15,223) were HIV-PCR tested by 14 (0-18) weeks of age, of whom 1.0% (174) were positive. When including all infant HIV tests in this cohort through to 24 months of age, WCPHDC identified an additional 136 infants with HIV, with total VT of 1.8%, nearly twice that at 14 weeks of age, and aligned with modelled VT of 2.1% by age 18 months. The WCPHDC is currently assessing prevalence of pretreatment ART resistance in infants acquiring HIV during breastfeeding despite maternal ART and have identified 141 such infants from July 2021 to October 2022 for resistance testing.
Conclusions: These results highlight the value of linked maternal-infant data and accounting for all infant tests to accurately assess VT.