Research Article: Further Evidence that Exclusive Breast-Feeding Reduces Mother-to-Child HIV Transmission Compared With Mixed Feeding

Date Published: March 11, 2008

Publisher: Public Library of Science

Author(s): Mary Glenn Fowler

Abstract: The author discusses the results of the Zambia Exclusive Breastfeeding Study, recently published inPLoS ONE.

Partial Text: The critical role of breast-feeding in improving infant and under-five-year survival in resource-limited settings has been well documented since the mid-1970s. A pooled analysis by the World Health Organization (WHO) of a number of studies on the impact of breast-feeding on child survival showed that the protective effect is strongest in the first six months of life, with a 4–6-fold survival benefit for breast-fed infants [1]. The benefit extends throughout the first year of life, with a 1.4–1.8-fold protective effect against mortality during months six through twelve [1].

With the emergence of the global HIV pandemic, prevention of mother-to-child transmission became an early research focus. The risk of transmission of HIV through breast-feeding was documented by observational studies from both developed and developing countries [2,3]. After the first one to two months of breast-feeding, where the risk of transmission is particularly high, several studies reported a continual sustained risk of infants becoming infected of between 0.6%–0.9% per month [3,4] during later breast-feeding. Studies also reported a cumulative absolute risk of 12%–16% postnatal transmission due to breast milk exposure when breast-feeding is extended to 18–24 months [5,6].

The carefully executed, prospective Zambia Exclusive Breastfeeding Study (ZEBS) by Louise Kuhn and colleagues, published recently in PLoS ONE, was carried out in Lusaka, Zambia from 2001–2004 [13]. While the ZEBS data on infant feeding and transmission outcomes are based on observational data, the relatively large sample size and the prospective design helped to address a number of the limitations of the earlier studies. The ZEBS analyses aimed a priori to test the hypothesis that exclusive breast-feeding was related to a reduction in transmission during the first months of life when compared with other types of infant feeding. The study also assessed the feasibility of intensive counseling to achieve high uptake of exclusive breast-feeding throughout the first four to six months of life. The findings add to and strengthen our understanding of the role of exclusive breast-feeding in protecting HIV-exposed infants against early postnatal HIV transmission.

There are a number of implications of these findings for clinical practitioners, researchers, and policy makers alike.

For programs aimed at preventing mother-to-child transmission of HIV, the encouraging data from the ZEBS on the protective role of exclusive breast-feeding reaffirm the need to promote exclusive breast-feeding for the majority of HIV-infected women in resource-limited settings throughout the first six months. This recommendation is based on 2001 guidance from WHO and UNICEF that exclusive breast-feeding should be supported in the first months of life unless “AFASS” criteria are met for replacement feeding: i.e., unless replacement feeding is “acceptable, feasible, affordable, sustainable, and safe” [14]. Counseling on infant feeding for newly delivered HIV-infected women should emphasize the importance of exclusive breast-feeding for at least six months unless the AFASS criteria are met. Women should be reassessed at six months after delivery to see if they can safely cease breast-feeding or whether instead they should continue breast-feeding with introduction of complementary foods. WHO has recently come out with updated HIV and Infant Feeding Guidelines that consider the ZEBS data as well as other new findings [15].