A.19.HIV incidence among HIV uninfected infants after 4-6 weeks of life
Chasela C, Chen Y, Hoffman I, Chilongozi D, Fiscus S, Taha TE, Goldenburg R, Fawzi W, Valentine M, Martinson F
Objectives: We looked at data from a randomized, double blind, controlled Phase III trial of antibiotics to prevent chorioamnionitis- associated perinatal HIV transmission done in 4 sites (Blantyre, Lilongwe, Dar –es-Salaam and Lusaka). This was to determine the incidence of HIV infection among infants whose HIV diagnostic test results were negative at birth and at 4-6 weeks and to identify factors leading to transmission and acquisition of HIV in these infants.
Methods: Whole blood from heel sticks was collected on filter paper (DBS) and HIV RNA was detected by a qualitative NucliSens assay or by quantitative Roche assay. Incidence rates, cumulative incidence rates and 95% confidence intervals for HIV incidence rates were calculated by the binomial approximation of incidence distributions. Risk factors associated with infant acquisition and mother transmission were based on cumulative incidence.
Results: There were 1538 HIV uninfected infants at 4 – 6 weeks of birth. The incidence at 3, 6, 9 and 12 months was similar with a cumulative incidence of 6.81%. There was a statistical significant difference between sites with Dar –es Salaam (3.51 95% CI 1.26, 5.76) having the lowest incidence and Lusaka (10.47 95% CI 8.22, 13.72) the highest. There was a significant difference in HIV transmission due to low haemoglobin (<8.64) and CD4 count, high plasma and cervical RNAs. After multivariable analysis high plasma and cervical RNA and low CD4 count remain significant. Conclusions: There was consistent HIV transmission throughout the observational period to 12 months. Maternal factors associated with HIV breast milk transmission were: lower CD4 count, and higher blood and cervical RNA burden.
Recommendations: Several on-going phase III clinical trials (using a variety of interventions including ART, exclusive breastfeeding, early weaning, and nutrition) are underway in Malawi to address this problem.