AEGiS-14IAC: Low gestational age at birth is strongly associated with vertical HIV-1 transmission in the perinatal antiretroviral prophylaxis era.

14th International AIDS Conference

Barcelona, Spain - July 7-12, 2002

Low gestational age at birth is strongly associated with vertical HIV-1 transmission in the perinatal antiretroviral prophylaxis era.

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. ThOrC1488)

Bulterys M, Wiener J, Nesheim S, Lindsay M, Palumbo P, Abrams E, Vink P, Fowler MG
CDC, Atlanta, GA, United States

BACKGROUND: In the United States (U.S.), much progress has been made towards the goal of maximally reducing perinatal HIV transmissions. However, infants born preterm remain an important risk group.

METHODS: The Perinatal AIDS Collaborative Transmission Study (PACTS) is a cohort study conducted in 4 U.S. cities. HIV-infected women were enrolled during pregnancy or within 60 days after delivery; HIV-exposed infants enrolled in the study were born between 1986 and 1999. Infant HIV status was determined by at least 2 positive results on DNA PCR.

RESULTS: Prior to 1994, gestational age (GA) was weakly associated with vertical HIV-1 transmission in PACTS. Among 1,063 mother-infant pairs who did not receive any antiretroviral prophylaxis, the relative risk (RR) of vertical HIV-1 transmission was 2.1 (95% CI = 1.4-3.3) for GA <32 weeks and 1.5 (95% CI= 1.2-2.0) for GA =32-36 weeks, compared with term infants. In contrast, among 595 infants born after 1/3/94 who received at a minimum antenatal, intrapartum, and neonatal zidovudine (25% also received combination antiretrovirals antenatally), the maternal viral load-adjusted RR of vertical HIV-1 transmission was 7.2 (95% CI = 2.6-20.1) for GA <32 weeks and 2.5 (95% CI = 1.4-4.6) for 32-36 weeks (test for trend, p<0.001). Based on positive DNA PCR results within 3 days of birth, there was no preponderance of presumptive intrauterine HIV-1 infections. Significant risk factors for HIV-1 infection among preterm infants included high maternal viral load peripartum (RR=8.0, 95% CI = 1.1-56.0) and >12 hours of ruptured membranes (RR=3.2, 95% CI = 1.3-8.0).

CONCLUSIONS: Among infants who received a 3-part regimen of antiretroviral prophylaxis, low GA was strongly associated with vertical HIV-1 transmission, even after adjustment for maternal viral load. Innovative strategies need to be evaluated to further reduce vertical HIV-1 transmission among women delivering preterm and their infants.

Keywords: AEGIS, Disease Transmission, Vertical, HIV-1, Zidovudine, HIV Infections, Viral Load, Anti-HIV Agents, Parturition, HIV, Acquired Immunodeficiency Syndrome, Gestational Age, Risk Factors, Infant, Premature, Delivery, Obstetric, Cohort Studies, Polymerase Chain Reaction, Mothers, Prenatal Care, United States, Infant, Human, Female, Infant, Newborn, Pregnancy, prevention & control, transmission, surgery, therapy

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ThOrC1488