Prevention of Mother to Child Transmission of HIV in Africa : Operational Research to Reduce Post-natal Transmission and Infant Mortality

Abstract: This thesis assesses the effectiveness of the National Prevention of Mother to Child Transmission of HIV (PMTCT) programme in 3 sites in South Africa, and the quality of infant feeding counselling across four countries, Botswana, Kenya, Malawi and Uganda . Implementation and outcome of PMTCT services were very different across the 3 sites. The Paarl site is achieving results comparable to clinical trial studies with a HIV-free survival rate of 85% at 36 weeks, while Umlazi is somewhat lower (74%) and Rietvlei, with HIV-free survival of 64%. Maternal viral load, prematurity and site were independent risk factors for infection and/or death. The regression analysis suggests that some of this difference is explained by the differences in quality of health systems across the sites. Traditional risk factors (e.g. viral load, prematurity) do not seem to explain the substantial differences in HIV-free survival between the Paarl and Rietvlei sites.The overall mortality rate for HIV exposed infants in this cohort was 155 per 1000 live births at 36 weeks, a level higher than most other HIV exposed cohorts. The excess mortality is occurring almost completely amongst HIV infected infants who had a nine fold increased risk of mortality compared with HIV exposed but HIV negative infants. There was no significant difference in 36 week survival rates between those HIV exposed but uninfected infants and those who were not HIV exposed, Hazard ratio 0.7 (95% CI 0.3-1.5).With respect to HIV and infant feeding most health workers across the four countries (234/334, 70%) were unable to correctly estimate the transmission risks of breastfeeding. Exposure to PMTCT training made little difference to this. Infant feeding options were mentioned in 307 out of 640 (48%) observations of PMTCT counselling session and in only 35 (5.5%) were infant feeding issues discussed in any depth; of these 19 (54.3%) were rated as poor. South Africa was similar with only two out of thirty four HIV positive mothers being asked about essential conditions for safe formula feeding before a decision was made. This body of work has demonstrated that the gap between efficacy and effectiveness can be significant.