Short course antiretroviral regimens such as AZT (Thai regimen), or nevirapine (Uganda HIVNET 012 regimen) given to HIV-infected women in pregnancy can reduce in utero and intrapartum transmission to their child by 40-50%. However, these gains are threatened by the continued transmission of HIV through breast milk of poor HIV-infected women in Africa who have no realistic choice but to breastfeed. A recent study from Durban compared for the first time, Mother-to-child transmission of HIV (MTCT) rates in each of the 3 feeding groups viz. exclusive breastfeeding (EBF), mixed breastfeeding (MBF) and formula feeding. The results of this study showed that at 3 months the MTCT in EBF mothers was similar to that in mothers giving only formula feeds, and the MTCT in EBF mothers was significantly lower than in those MBF (14.6% vs. 24.1%). This suggested that EBF may carry no additional risk of MTCT of HIV1 over formula feeding. A prospective study is required to verify these findings.
We propose a cohort study of HIV-infected mothers and their infants, to examine the risk of post-natal transmission of HIV in relation to infant feeding practices after mothers receive intensive breastfeeding counselling and support to practise EBF until about 6 months of age (the optimal duration for EBF).
The hypothesis being tested is: Exclusive breastfeeding by HIV-infected women carries no additional risk of post-natal transmission of HIV than exclusive formula feeding.
The primary objectives of the study are to determine the effect of infant feeding practices on HIV infection rates of infants at 6 and 22 weeks of age, and secondly to to determine the infant survival rate at 24 months of age according to feeding practices and HIV status.
Secondary objectives are:
i) To determine the HIV infection rate of infants as measured of a sample collected within 72 hours of birth; ii) To determine the HIV transmission incidence attributable to the duration of different feeding practices; iii) To determine the cumulative incidence of vertical transmission in EBF, MBF and EFF infants; iv) To describe risk factors, other than feeding practice, for post-natal transmission of HIV, including maternal and infant morbidity and breast health; v) To assess the determinants of transmission in MBF adjusting for exposure factors e.g. type and age of introduction of other food/milk; vi) To describe the morbidity and growth of infants in relation to feeding practices and HIV status; and vii) To describe adherence rates to EBF following a breastfeeding support intervention.
HIV infected women will be counselled according to the WHO/UNICEF/UNAIDS infant feeding guidelines. All HIV-infected women and a random sub-sample of HIV-uninfected women will be recruited antenatally. Those who choose to breastfeed will be visited frequently at home by a team of breastfeeding counsellors before and after delivery to promote and support EBF. HIV-infected mothers who choose not to breastfeed will be supported in their choice by clinic-based staff. An independent team of field monitors will collect data weekly on feeding practices and morbidity of all infants at home visits. Blood samples will be collected by finger/heel prick and stored on filter paper prior to qualitative and quantitative estimation of HIV viral content to determine the timing of transmission.
