Abstract:
BACKGROUND : Eliminating mother-to-child transmission of HIV is a global public health target. Robust, feasible
methodologies to measure population level impact of programmes to prevent mother-to-child transmission of HIV
(PMTCT) are needed in high HIV prevalence settings. We present a summary of the protocol of the South African
PMTCT Evaluation (SAPMTCTE) with its revision over three repeated rounds of the survey, 2010–2014.
METHODS : Three cross sectional surveys (2010, 2011–2012 and 2012–2013) were conducted in 580 primary health
care immunisation service points randomly selected after stratified multistage probability proportional to size
sampling. All infants aged 4–8 weeks receiving their six-week immunisation at a sampled facility on the day of the
visit were eligible to participate. Trained research nurses conducted interviews and took infant dried blood spot
(iDBS) samples for HIV enzyme immunoassay (EIA) and total nucleic acid polymerase chain reaction (PCR) testing.
Interviews were conducted using mobile phones and iDBS were sent to the National Health Laboratory for testing.
All findings were adjusted for study design, non-response, and weighted for number of South African live-birth in
each study round. In 2012 a national closed cohort of these 4 to 8-week old infants testing EIA positive (HIV
Exposed Infants) from the 2012–2013 cross-sectional survey was established to estimate longer-term PMTCT impact
to 18 months. Follow-up analyses were to estimate weighted cumulative MTCT until 18 months, postnatal MTCT
from 6 weeks until 18 months and a combined outcome of MTCT-or-death, using a competing risks model, with
death as a competing risk. HIV-free survival was defined as a child surviving and HIV-negative up to 18 months or
last visit seen. A weighted cumulative incidence analysis was conducted, adjusting for survey design effects.
DISCUSSION : In the absence of robust high-quality routine medical recording systems, in the context of a generalised
HIV epidemic, national surveys can be used to monitor PMTCT effectiveness; however, monitoring long-term outcomes
nationally is difficult due to poor retention in care.
