LAUSR

INTRODUCTION Enhanced postnatal prophylaxis (ePNP) is recommended in infants of women with viraemia during labour, as identified by viral load (VL) testing late in pregnancy. However, data on use of antenatal VL to predict peripartum viraemia are few, particularly in women starting antiretroviral therapy (ART) in pregnancy who experience initial VL declines. METHODS Between January 2016 and August 2017, we identified HIV-infected women who initiated ART (tenofovir, emtricitabine and efavirenz) antenatally and had a VL<400 copies/mL prior to delivery in Cape Town, South Africa. VLs were repeated post-delivery and sensitivity, specificity and positive and negative likelihood ratios (LR+ and LR-) for antenatal VL<100 copies/ml in predicting peripartum VL<100 and <400 copies/mL were calculated. RESULTS Among 322 women (median age 29 years, 44% with a history of previous ART use, median gestation of antenatal VL 33 weeks), antenatal VL was <100 copies/mL in 89% and 100-400 copies/mL in 11%. At a median 9 days postpartum, 91%, 7%, and 2% women had a VL <100, 100-400, and >400 copies/mL, respectively. Sensitivity of antenatal VL <100 copies/mL in predicting peripartum VL <100 copies/mL was 0.95 (95% CI 0.92-0.97) and specificity was 0.71 (95% CI 0.51-0.87; LR+ 3.32, LR- 0.07). Performance was slightly weaker to detect peripartum VL <400 copies/mL but was similar across strata of gestation at antenatal VL and history of ART use. DISCUSSION Antenatal VL is a useful predictor of peripartum viraemia in women who started ART in pregnancy and attained a VL <400 copies/mL antenatally and may be used to target ePNP interventions.