Cohort Profile: Mamanengane or the Africa Centre Vertical Transmission Study

From the mid-1990s, the success of antiretroviral prophylaxis to reduce HIV RNA viral load in plasma and avoidance of breastfeeding provided the real possibility that mother-to-child transmission (MTCT) of HIV-1 could be markedly reduced, with an implicit understanding that these measures could be effectively applied to all HIV-infected women in developing countries. The latter constitute the overwhelming majority of HIV-positive pregnancies resulting in approximately half a million new infant infections annually. However, the inappropriate use of formula milks amongst impoverished populations resulted in major adverse effects; without the nutritional and immunological benefits of breastfeeding, growth failure, malnutrition, diarrhoea and infant death are common. Since 1996, a group at the Nelson Mandela School of Medicine, University of KwaZulu-Natal (UKZN), had been pursuing the idea of finding interventions to reduce breastfeeding transmission of HIV-1 that would be suitable and safe for populations living in resource-poor settings. The aim was to find efficacious, ethical, acceptable, feasible and sustainable approaches to prevent post-natal transmission, while preserving the critical practice of breastfeeding. The presentation of preliminary evidence in 1999 from the UKZN group that exclusive breastfeeding (EBF) might be associated with lower HIV transmission than mixed breastfeeding (MBF) suggested that such an aim would be possible, although considerable international scientific opposition to attempts to promote breastfeeding in an high HIV prevalence setting remained. Subsequently, with support from the Wellcome Trust, UK, the availability of a populationbased site at the Africa Centre for Health and Population Studies (www.africacentre.ac.za), and confluence of interests among a small number of individuals, the conditions were created for the Vertical Transmission Study (VTS), a non-randomized cohort intervention study, described here. (‘Mamanengane’ is the Zulu name for the study and means ‘Mother and Child.’) Ethical approval was granted by the Biomedical Research Ethics Committee of UKZN, pilot work began in 1999 and clinical follow-up of the study was completed in September 2006.