Compliance to Viral Load Monitoring Schedules Among Women Attending Prevention of Vertical HIV Transmission Services Before and During the COVID-19 Pandemic in Ehlanzeni District, Mpumalanga, South Africa.

Human immunodeficiency virus (HIV) viral load (VL) monitoring was likely interrupted during the Coronavirus disease 2019 (COVID-19) pandemic. We used routine data on repeat VL testing among 667 prevention of vertical HIV transmission (PVT) clients in Ehlanzeni district, to determine compliance to VL testing recommendations and associated factors during different time periods: pre-COVID-19, transition, and COVID-19. Descriptive and multivariable Poisson regression analyses were conducted, with and without including revised PVT-guidelines rolled out in January-2020. Among 405 women with ≥ 2 VL tests, the overall median age was 30 years (interquartile range: 26-35 years). Compliance to recommended VL testing guidelines ranged between 81.5% (172/211) and 92.3% (191/207) at different time periods. Across all three periods and when revised PVT-guidelines were used, being compliant was significantly reduced among those with earliest VL = 50-999 copies/ml (incidence rate ratio (IRR) = 0.71 [95% confidence interval (CI) 0.61-0.82], p value < 0.001) and VL ≥ 1000 copies/ml (IRR = 0.18 [95% CI 0.09-0.36], p value < 0.001). When guideline revisions were excluded, compliance was only significantly reduced among those with VL ≥ 1000 copies/ml (IRR = 0.14 [95% CI 0.06-0.32], p value < 0.001) and increased during the COVID-19 period versus pre-COVID-19 (IRR = 1.10 [95% CI 1.05-1.15], p value < 0.001). Similar significant associations between compliance and VL level were observed when the COVID-19 period was analyzed separately. Significantly increased compliance to VL testing among the 25-34 years age-group versus younger women was also observed across all periods. These results highlight the importance of strengthening strategies such as short message service reminders and educational messaging, reaching all age-groups, to fast-track implementation targets for VL monitoring.