Prevalence of antiretroviral therapy treatment failure among HIV-infected pregnant women at first antenatal care: PMTCT Option B+ in Malawi.

Background: In Malawi's PMTCT Option B+ program, HIV-infected pregnant women who are already receiving ART are continued on their current therapy regimen without testing for treatment failure at the first antenatal care (ANC) visit. HIV RNA screening at ANC may identify women with treatment failure and ensure that viral suppression is maintained throughout the pregnancy.

Methods: We conducted a cross-sectional study of HIV-infected pregnant women who had been receiving ART for at least 6 months at the first ANC visit under the PMTCT Option B+ program at Bwaila Hospital in Lilongwe, Malawi from June 2015 to December 2017. Poisson regression models with robust variance were used to investigate the predictors of ART treatment failure defined as viral load ≥1000 copies/ml.

Results: The median age of 864 women tested for ART failure was 31.1 years (interquartile range: 26.9-34.5). The prevalence of treatment failure was 7.6% (95% confidence interval (CI): 6.0-9.6). CD4 cell count (adjusted prevalence ratio (aPR) = 0.57; 95% CI: 0.50-0.65) was strongly associated with treatment failure.

Conclusion: The low prevalence of treatment failure among women presenting for their first ANC in urban Malawi demonstrates success of Option B+ in maintaining viral suppression and suggests progress towards the last 90% of the UNAIDS 90-90-90 targets. Women failing on ART should be identified early for adherence counseling and may require switching to an alternative ART regimen.