Maternal HIV viral load threshold for guiding extended infant prophylaxis

Abstract

OBJECTIVES: Infant postnatal prophylaxis (PNP) is universally recommended for all breastfed infants born from mothers living with HIV up to 6-weeks of age. Continuation of PNP was recommended for infants defined as at high-risk of HIV acquisition. We hypothesised that a single maternal viral load (mVL) at the end of the universal PNP period can accurately identify infants requiring extended prophylaxis. METHODS: We assessed 1398 VL of breastfeeding mothers from Zambia and Burkina Faso at baseline (week 6-8), months 6 and 12 post-partum. Infants were defined at high-risk of HIV acquisition when mVL was ≥ 1000 cp/mL. RESULTS: Mothers with a VL between 40 and 1000 cp/mL or ≥ 1000 cp/mL at baseline were 6 [95CI 3.7-9.6] or 18 [95CI 12.6-25.7] times more likely to have a VL above 1000 cp/mL during breastfeeding than mothers with a VL below 40 cp/mL. A 40 cp/mL threshold for mVL showed a better performance to identify infants eligible for extended PNP in comparison with the standard threshold. CONCLUSION: A single mother VL at W6-8 enabled a sensitive identification of infants at risk of HIV acquisition throughout the breastfeeding period. This conclusion may pave the way for a simplified risk-stratified guideline for the initiation of extended infant PNP.