Low mother-to-child HIV transmission using Option A in South Africa

First population-level effectiveness evaluation of a national programme to prevent HIV transmission from mother to child, South Africa.

Goga AE, Dinh TH, Jackson DJ, Lombard C, Delaney KP. J Epidemiol Community Health. 2015 Mar;69(3):240-8. doi: 10.1136/jech-2014-204535. Epub 2014 Nov 4.

Background: There is a paucity of data on the national population-level effectiveness of preventing mother-to-child transmission (PMTCT) programmes in high-HIV-prevalence, resource-limited settings. We assessed national PMTCT impact in South Africa (SA), 2010.

Methods: A facility-based survey was conducted using a stratified multistage, cluster sampling design. A nationally representative sample of 10 178 infants aged 4-8 weeks was recruited from 565 clinics. Data collection included caregiver interviews, record reviews and infant dried blood spots to identify HIV-exposed infants (HEI) and HIV-infected infants. During analysis, self-reported antiretroviral (ARV) use was categorised: 1a: triple ARV treatment; 1b: azidothymidine >10 weeks; 2a: azidothymidine ≤10 weeks; 2b: incomplete ARV prophylaxis; 3a: no antenatal ARV and 3b: missing ARV information. Findings were adjusted for non-response, survey design and weighted for live-birth distributions.

Results: Nationally, 32% of live infants were HEI; early mother-to-child transmission (MTCT) was 3.5% (95% CI 2.9% to 4.1%). In total 29.4% HEI were born to mothers on triple ARV treatment (category 1a) 55.6% on prophylaxis (1b, 2a, 2b), 9.5% received no antenatal ARV (3a) and 5.5% had missing ARV information (3b). Controlling for other factors groups, 1b and 2a had similar MTCT to 1a (Ref; adjusted OR (AOR) for 1b, 0.98, 0.52 to 1.83; and 2a, 1.31, 0.69 to 2.48). MTCT was higher in group 2b (AOR 3.68, 1.69 to 7.97). Within group 3a, early MTCT was highest among breastfeeding mothers [11.50% (4.67% to 18.33%) for exclusive breast feeding, 11.90% (7.45% to 16.35%) for mixed breast feeding, and 3.45% (0.53% to 6.35%) for no breast feeding]. Antiretroviral therapy or >10 weeks prophylaxis negated this difference (MTCT 3.94%, 1.98% to 5.90%; 2.07%, 0.55% to 3.60% and 2.11%, 1.28% to 2.95%, respectively).

Conclusions: SA, a high-HIV-prevalence middle income country achieved <5% MTCT by 4-8 weeks postpartum. The long-term impact on PMTCT on HIV-free survival needs urgent assessment.

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Editor’s notes: WHO recommends a comprehensive approach to preventing mother-to-child HIV transmission. These include primary prevention of HIV among women of childbearing age, prevention of unintended pregnancies among women living with HIV, prevention of HIV transmission from a woman living with HIV to her infant and the provision of appropriate treatment, care and support to mothers living with HIV, their children and families. In 2010 WHO revised their ART guidelines on preventing mother-to-child HIV transmission. The guidelines distinguished two groups of women. The first group with low CD4 cell counts were eligible for ART for their own health (≤350 cells/mm³) and were started on ART, and the second group with higher CD4 cell counts (>350 cells/mm³) were not yet eligible for ART and were initiated on short-course ARV prophylaxis. South Africa’s national programme adopted WHO Option A: antepartum daily zidovudine (AZT) from 14 weeks onwards for the mother and daily nevirapine (NVP) prophylaxis for six weeks postpartum for the infant.

This study assessed the early population-level effectiveness looking at mother-to-child HIV transmission between four to eight weeks, by examining about 10 000 mother-infant pairs from the nine provinces in South Africa in 2010. The study therefore provides a countrywide estimate of the effectiveness of the South African programme for the prevention of mother-to-child HIV transmission in 2010.

The study found low levels of early mother-to-child HIV transmission, 3.5% at four to eight weeks post-partum, in this high-prevalence setting. About one third of infants were HIV exposed infants (HEI). The authors postulate that these low levels of mother-to-child HIV transmission are driven by a high proportion of women receiving ART or ARV prophylaxis, 85%, combined with the low levels of breastfeeding. Some 61% of mothers reported formula feeding.

However, in many countries in sub-Saharan Africa, breastfeeding is judged to be the most appropriate choice of infant feeding for women living with HIV, which limits the generalisability of these findings. Moreover, the authors acknowledge that the study reports on early transmission, four to eight weeks post-partum, and emphasize that more data is urgently needed on long-term effectiveness of preventing mother-to-child HIV transmission, using infant HIV-free survival by 24 months postpartum. 

Interestingly the authors found a high proportion of unintended pregnancies. Some 61% of HEI were unplanned, demonstrating an important gap in WHO’s comprehensive strategy on preventing mother-to-child HIV transmission.

In January 2015, the South African Department of Health replaced Option A with Option B+. Now all pregnant and breastfeeding women living with HIV are eligible for lifelong ART irrespective of clinical or immunological stage.

South Africa
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