Risk factors for postnatal mother-child transmission of HIV-1

Objective: To identify factors affecting HIV-1 breastfeeding transmission. Design: Longitudinal observational cohort study. Methods: HIV-1 seropositive pregnant women and seronegative controls were e nrolled at a maternity hospital in Nairobi. Women and their children were f ollowed from birth, and data on HIV-1 transmission, breastfeading, clinical illness, and growth were collected. Specimens for HIV-1 serology and/or po lymerase chain reaction were obtained at birth, 2, 6, and 14 weeks, 6, 9, 1 2, and 18 months, and every 6 months thereafter. Children were classified a s HIV-1 uninfected, perinatally, or postnatally infected. Potentially breas tfeeding transmission related risk factors were compared between postnatall y infected and uninfected children. Results: Among children born to seropositive or seroconverting mothers, 317 were uninfected, 51 infected perinatally and 42 infected postnatally. Iden tified risk factors for postnatal transmission were maternal nipple lesions (OR = 2.3, CI 95% 1.1-5.0), mastitis (OR = 2.7, CI 95% 1.1-6.7), maternal CD4 cell count < 400 mm(3) (OR = 4.4, CI 95% 1.9-9.9), maternal seroconvers ion while breastfeeding (OR = 6.0, CI 95% 1.8-19.8), infant oral thrush at <: 6 months of age (OR = 2.8, CI 95% 1.3-6.2) and breastfeeding longer than 15 months (OR = 2.4, CI 95% 1.2-5.1). All factors, except maternal serocon version due to its rarity, were independently associated with an increased postnatal transmission risk by multivariate logistic regression analysis. Conclusion: In addition perinatal antiretroviral therapies, public health s trategies should address: (i) prevention of maternal nipple lesions, mastit is and infant thrush; (ii) reduction of breastfeeding duration by all HIV-1 -infected mothers; (iii) absolute avoidance of breastfeeding by those at hi gh risk, and (iv) prevention of HIV-1 transmission to breastfeeding mothers . (C) 2000 Lippincott Williams & Wilkins.