Impact of point-of-care maternal viral load testing at delivery on vertical HIV transmission risk assessment and neonatal prophylaxis: a cluster randomized trial

Abstract

Introduction: Despite global reductions in vertical HIV transmission (VHT), 120,000 children newly acquired HIV in 2023. High maternal viral load (VL) is a major risk factor for VHT. We estimated the impact of point-of-care (PoC) maternal VL testing at delivery in profiling the risk of VHT and its impact on appropriate postnatal prophylaxis for infants born to women living with HIV (WLWH).

Methods: The cluster-randomized LIFE (Long term Impact on inFant hEalth) study was conducted at 28 health facilities in Tanzania and Mozambique from 2019 to 2021. At delivery, the intervention arm applied PoC maternal VL plus clinical criteria for VHT risk assessment, while the control arm used clinical criteria only. In Tanzania, both arms provided ePNP based on maternal risk factors, while Mozambique provided ePNP universally. We used mixed effects logistic regression to estimate the intervention effect on the proportion of infants at high risk (Tanzania and Mozambique) and infants at high risk receiving ePNP (Tanzania only).

Results: A total of 6467 WLWH were enrolled: 66.3% were diagnosed before the third trimester, 99% were on antiretroviral therapy and 78% were virally suppressed at delivery. Of 6564 newborns of WLWH included, 774 (11.7%) were identified to be at a high risk: 629 (19.3%) versus 145 (4.4%) in intervention and control arms, respectively; p<0.0001. In the intervention arm, 520 (82.7%) infants at high risk were classified only based on maternal PoC VL at delivery. In the control arm, 720 (21.8%) additional infants at high risk would have been identified if their mothers had received PoC VL assessment. In Tanzania, infants at high risk in the intervention arm were significantly more likely to receive ePNP: 59.5% versus 31.4% (OR 4.42, 95% CI: 1.09, 17.89). However, 40.5% from intervention arm and 68.6% from control arm did not receive ePNP despite high-risk classification at delivery.

Conclusions: PoC maternal VL testing at delivery significantly increased the proportion of infants identified to be at high risk. Infants at high risk whose mothers received PoC VL at delivery were more often initiated on ePNP. However, the linkage of infants at high risk to appropriate prophylaxis remains suboptimal, warranting consideration of universal ePNP.

Keywords: HIV acquisitions; infant; newborn; point‐of‐care systems; risk assessment; viral load.

Figure 1

Proportions of infants at high risk for vertical HIV transmission by study arm. Denominator includes all included infants (large donuts) and all infants at high risk (small donuts). ^aNumber of twins/multiples included in denominator. ART <4wks, initiated antiretroviral treatment less than 4 weeks prior to delivery; High VL deliv., high viral load at delivery; High VL 4wks, high viral load in the past 4 weeks; Multiple, multiple high‐risk criteria; New HIV Dx, newly diagnosed with HIV at delivery.

Figure 2

Proportion of infants at high risk for vertical HIV transmission in the control arm including retrospective VL results at delivery, representing the proportion of infants who could have been identified as high risk if maternal PoC VL testing had been available at the health facility (dark blue). Reasons for high‐risk classification indicated by colours. Multiple high‐risk category includes two or more reasons for high‐risk classification. Denominator includes all included infants. High VL deliv. (retro) refers to VL testing performed retrospectively at the central laboratory and not available in real‐time. NA represents infants for whom retrospective maternal VL results were not available due to sample lost in transit to central laboratory, coagulated blood or otherwise unusable sample, or result not recorded or recorded as “error.” ^aNumber of twins/multiples included in denominator. ART <4wks, initiated antiretroviral treatment less than 4 weeks prior to delivery; High VL deliv. (retro.), high viral load at delivery, measured retrospectively; High VL 4wks, high viral load in the past 4 weeks; Multiple, multiple high‐risk criteria; New HIV Dx, newly diagnosed with HIV at delivery.

Figure 3

Proportion of infants at high risk in Tanzania initiated on enhanced postnatal HIV prophylaxis. Colours indicate prophylactic regimen. ePNP, enhanced postnatal prophylaxis; PNP, postnatal prophylaxis.