Preterm Infants Show No Increase in HIV Acquisition vs Full-Term Infants Exposed in Utero

The acquisition of HIV was not found to be higher in infants born preterm who were exposed to HIV in utero compared with infants born at term, according to a study published in the Southern African Journal of HIV Medicine.

Comprehensive prevention of mother-to-child transmission of HIV is offered in Botswana, a country in sub-Saharan Africa. Treatment and prevention of HIV was scaled up in 2016 to allow all pregnant women living with HIV (WLHIV) to gain access to antiretroviral treatment (ART), which in turn exposes infants in utero to ART.

This study aimed to describe prevalence and timing of acquisition of HIV in utero vs perinatal in infants who had perinatal exposure to HIV and were born preterm compared with those born at term.

Interracial family holding baby feet in hands mixed by black and white skin color | Image credit: Shotmedia - stock.adobe.com

The Mpepu study was used to collect a cohort of mothers and children that were exposed to HIV. It was a randomized controlled trial that recruited pregnant WLHIV from public antenatal clinics, with enrollment of women during pregnancy or up to a month after the infant was born. Visits occurred at birth or enrollment, 14-34 days after birth, and 2, 3, 6, 9, 12, 15, and 18 months after birth from May 2011 to January 2013. Pregnant WLHIV received 3-drug ART during pregnancy and breastfeeding. All neonates who had exposure to HIV were recommended to take Nevirapine and Zidovudine as single doses for the first 4 weeks of life. All infants had HIV DNA testing done to confirm diagnosis of HIV. Transmission in utero was determined if the positive DNA test came at birth with a positive test at 14-34 days to confirm.

A total of 2866 mother-infant pairs were used for this study, with 81% of infants born at or after 37 weeks of gestation and 19% born preterm. A total of 51% were female, the median birth weight was 2.9 kg, and 17.2% were born weighing less than 2.5 kg. All infants were randomized into a placebo or cotrimoxazole (CTX) prophylaxis group and randomization occurred after a median (range) of 28 (14-34) days. Infants were primarily formula-fed (79.1%) whereas only 20.6% were breastfed. Most mothers received 3-drug ART (82.5%) compared with 12.3% who received zidovudine and 5.2% who did not receive treatment.

A total of 17 infants were infected with HIV overall for a 0.6% mother-to-child transmission rate. The prevalence of HIV between infants born preterm vs those born at term had no observed difference (0.8% vs 0.6%). There were also no differences in prevalence of HIV at birth (0.2% vs 0.3%) and at 14-34 days after delivery (0.6% vs 0.3%) in those born preterm vs those born at term, respectively.

A multivariable analysis found that the odds of an infant acquiring HIV at 34 days after birth decreased as maternal age increased by a year and in infants who were born to WLHIV who took ART for prophylaxis. Infants who were born to WLHIV who had labor that lasted for longer than 24 hours had increased odds of acquiring HIV in utero (OR, 10.42; 95% CI, 1.23-88.35). Odds of acquiring HIV in the peripartum period decreased with maternal age increasing by a year (OR, 0.89; 95% CI, 0.80-0.99) and in infants whose mother took ART for prophylaxis.

There were some limitations to this study. There was a low rate of mother-to-child transmission observed, which could have reduced the power to detect the difference in acquisition of HIV between groups. The analysis was only done through 34 days after birth and could have underestimated the peripartum acquisition of HIV, although the 18-month follow-up did not observe any seroconversion occurring after 34 days.

There were no increases in the risk of acquisition of HIV overall in utero and peripartum in infants born preterm vs born at term. Future studies should focus on populations that would give the results more power to differentiate the risk.

Reference

Ajibola G, Mdluli C, Bennett K, et al. No increased in utero and peripartum HIV acquisition risk in HIV-exposed preterm infants. South Afr J HIV Med. 2023;24(1):a1509. doi:10.4102/sajhivmed.v24i1.1509