For the public health systems of countries with high prevalences of infection with the human immunodeficiency virus (HIV), the identification of HIV-infected pregnant women and their treatment with antiretroviral drugs are among the greatest opportunities and challenges. Reliable and robust methodologies for measuring and demonstrating the success of such identification and treatment, especially when applied on a large scale, are needed. (1)
When combinations of antiretroviral drugs are given to HIV-positive women, either as lifelong treatment or as prophylaxis to prevent mother-to-child transmission of HIV, the rate of HIV transmission from mothers to non-breastfed infants can be reduced to < 1%. (2,3) In breastfeeding communities, the additional postnatal transmission can similarly be reduced to < 1% when viral load is effectively suppressed? The possibility of reducing the prevalences of HIV infection among HIV-exposed infants to such exceptionally low levels has inspired the belief that the elimination of HIV infection in infants is attainable. Current goals are to reduce paediatric infections by 90% and the rates of mother-to-child transmission in breastfeeding populations to < 5% by 2015. (5)
Measurement of the effectiveness of interventions for the prevention of mother-to-child transmission (PMTCT) has several benefits: it encourages health workers to believe that they can change, at least for children, the course of the HIV epidemic; it helps fundraising, by providing donors with evidence that their investments are worthwhile; and it provides feedback to health managers about whether challenges to implementation have been effectively resolved.
HIV prevalence in the South African province of KwaZulu-Natal is among the highest in the world. In 2008, for example, HIV prevalence among women attending government-run antenatal clinics in the province was 38.7%. (6) In April of the same year, KwaZulu-Natal's Department of Health bolstered its PMTCT programme to provide antenatal zidovudine from 28 weeks' gestation to HIV-infected pregnant women, in addition to the single-dose nevirapine it was already providing to such women and their babies at the time of delivery. At this time, the province's Department of Health also commissioned an impact assessment to determine to what extent the programme's goal, to reduce HIV infection in infants, was being achieved. We report the findings of a study, designed to determine the rates of mother-to-child transmission of HIV in KwaZulu-Natal, in which all infants attending immunization clinics for their first immunizations served as a population proxy. Since > 95% of infants in KwaZulu-Natal attend such clinics for their first immunization, (7) the sample included infants whose mothers might not have participated in the province's PMTCT programme.
Participants were enrolled in a cross-sectional study conducted between May 2008 and April 2009. ]he study, which was designed to assess the impact of the provincial PMTCT programme in KwaZulu-Natal, South Africa, included all primary-health-care facilities in six of the 11 districts of KwaZulu-Natal. All fixed clinics providing immunizations in the six study districts were included in the sample; mobile clinics were excluded. The study districts were primarily urban (three) or primarily rural (three) and were purposively selected in collaboration with KwaZulu-Natal's Department of Health. At the time of the study, the six study districts had a combined population of 7.1 million, representing about 69.5% of the population of KwaZulu-Natal. (8) All mothers with children aged < 6 years and all fathers and legal guardians with infants aged 4-8 weeks who attended the study immunization clinics were invited to participate in the parent study. Children attending with other caregivers were excluded because the other caregivers would be unable to provide consent for blood sampling or, it was felt, provide reliable information about the HIV status of the mother and child. …