New Study by MSH Published by PLOS ONE Evaluates the Impact of Prevention of Mother-to-Child Transmission of HIV in Malawi through Immunization Clinic-Based Surveillance

A new study published in PLOS ONE offers a potentially easy and cost-effective strategy for evaluating the efficacy of Malawi’s Option B+ Prevention of Mother-to-Child Transmission of HIV (PMTCT) program. The study describes a surveillance approach to obtain population-based estimates of the vertical transmission rate (VTR) of infants exposed to HIV from their mothers in Malawi immediately after the adoption of the Option B+ strategy.

In 2011, the Malawian government, with support from MSH, was the first to adopt the Option B+ strategy, offering all HIV-infected pregnant and breastfeeding women antiretroviral therapy (ART) for life, regardless of clinical stage or CD4 count.

“Two months after the adoption of Option B+, but prior to widespread scale-up of its use, we developed a strategy to evaluate Malawi’s PMTCT program.  We derived population-based estimates of the VTR by testing a sample of infants presenting for their first immunization clinic visit in four districts. Comparing this estimate of VTR to the results of subsequent evaluations of the national program (now that Option B + is the established strategy in Malawi), will allow Malawi to assess trends in the effectiveness of the national PMTCT program for young infants and, by extension, the effectiveness of Option  B+, “ said Dr. Scott Kellerman, MSH Global Technical Lead for HIV & AIDS and senior author on the study.  “In addition, this study demonstrates the potential for routine testing at immunization clinics to monitor mother-to-child transmission (MTCT) rates in Malawi and illustrates the feasibility of this approach for regular data collection for surveillance purposes,” said Dr. Kellerman.

Between September and November 2011, MSH and colleagues evaluated the national PMTCT program in four Malawi districts. Dried blood spot samples (DBS) were tested from infants less than 3 months of age presenting for their first immunization visit for maternal HIV antibodies and, in those positive, for DNA polymerase chain reaction to calculate a population based HIV VTR. MSH and colleagues sampled caregivers and infants less than 3 months old from 53 randomly chosen immunization clinics in 4 districts.

Of the 5,068 DBS samples, 764 were ELISA positive indicating 15.1% (14.1-16.1%) of mothers were HIV-infected and passed antibodies to their infant. Sixty-five of the ELISA-positive samples tested positive by DNA PCR, indicating a vertical transmission rate of 8.5% (6.6-10.7%). Survey data indicates 64.8% of HIV-infected mothers and 46.9% of HIV-exposed infants received some form of antiretroviral prophylaxis. Results do not include the entire breastfeeding period which extends to almost 2 years in Malawi.

 The observed VTR was lower than expected given earlier modeling estimates, suggesting that Malawi’s PMTCT program has been successful at averting perinatal HIV transmission. Challenges to full implementation of PMTCT remain, particularly around low reported antiretroviral prophylaxis.

“This approach is a useful surveillance tool to assess changes in PMTCT effectiveness as Option B+ is scaled-up and can be expanded to track programming effectiveness for young infants over time in Malawi and elsewhere, “ said Dr. Kellerman.  “In addition, as we get closer to our goals of eliminating mother to child transmission, this tool may provide a good mechanism to track progress towards that goal. “

Authors of the article include: Michele A. Sinunu of Boston University School of Public Health; Erik J. Schouten of MSH in Lilongwe, Malawi; Nellie Wadonda-Kabondo, Enock Kajawo, Michael Eliya, Kundai Moyo, Frank Chimbwandira, and  Lee Strunin of the Malawi Ministry of Health, and Scott E. Kellerman, of MSH.

Read the article on PLOS ONE

For more on MSH’s work on PMTCT, visit here.