Nutrition News for Africa

Abstract - April 30, 2007

An article entitled “Mother-to-child transmission of HIV-1 infection during exclusive breastfeeding in the first 6 months of life: an intervention cohort study” was published by Coovadia et al. in The Lancet 2007;369:1107-16 

Introduction: Every year, hundreds of thousands of infants continue to become infected with HIV through breastfeeding, even when programs are available that offer HIV testing to pregnant women and antiretroviral prophylaxis for those infected. The risks of exclusive breastfeeding by HIV-infected mothers in developing countries have not been adequately reported. Both clinical trials and operational research settings have shown conflicting serious morbidity and mortality risks associated with the free provision of replacement feeds. The authors implemented a study to assess the HIV transmission risks and survival associated with exclusive breastfeeding and other types of infant feeding.

Methods: HIV infected and uninfected pregnant women attending antennal clinics in KwaZulu Natal were enrolled into a non-randomized intervention cohort study. Single-dose nevirapine was provided for all HIV-infected women and their infants and all women were counseled antenatally about infant-feeding options. Commercial infant formula was offered free. After delivery, all mothers and their infants were visited at home by infant-feeding counselors 3-4 times in the first 2 weeks of life and every 2 weeks thereafter until the infant was 6 months old. Counselors and clinic-based study nurses supported mothers to breastfeed exclusively or to replacement feed exclusively according to their choice. Mothers reported feeding practices to an independent group of field monitors who visited every week. Mothers and infants attended clinics 6 weeks after delivery and every month thereafter until 6 months. At every visit the study nurse measured the infant, recorded any morbidity events, and obtained a dried blood spot sample from the infant, and a breastmilk sample from the mother. Clinic nurses and HIV counselors advised HIV-infected women to stop all breastfeeding when infants were 6 months old. 

Results: Between October 2001 and April 2005, 1,372 HIV-infected mothers had 1,405 infants, 1,345 HIV-uninfected had 1,369, and five had indeterminate HIV-infection status. The analysis focuses on HIV-infected mothers and their infants. More women who chose to replacement feed had CD4-cell counts less than 200 cells/ μL than did those choosing to exclusively breastfeed. Infants who were breastfed but also received solids any time after birth were nearly 11 times more likely to acquire infection than were exclusively breastfed children. Infants born to mothers with CD4-cell counts less than 200/ μL were almost four times more likely to acquire HIV or die than were those born to mothers with CD4-cell counts greater than 500/ μL, and those born to mothers with CD4-cell counts between 200 and 500 cells/ μL were 2.2 times more likely to acquire HIV or die.

Discussion: This study accords with earlier reports that exclusive breastfeeding carries a significantly lower risk of HIV transmission than do all types of mixed breastfeeding. Infants who received formula milk in addition to breastmilk were nearly twice as likely to be infected as were infants who received breastmilk only. Most women sustained exclusive breastfeeding for long periods, resulting in very few infants being mixed fed, and thus limiting the possibility of making a comparative analysis. Results show that the Kaplan-Meier estimated risk of postnatal transmission of HIV by 20–26 weeks of age in exclusively breastfed infants who were negative at 6 weeks of age was 4.04%. Infant’s sex did not affect either feeding practices or the rate of postnatal transmission. Mortality in the first 3 months of life was 15% in the group receiving replacement feeding and 6% with the exclusive breastfeeding group. The authors confirm that the key demonstration of this study is that early introduction of solid foods and animal milks increases HIV transmission risks compared with exclusive breastfeeding from birth. The authors conclude that these data, together with evidence that exclusive breastfeeding can be supported in HIV-infected women, warrant revision of the present UNICEF, WHO, and UNAIDS infant feeding guidelines that were last revised in 2000.