The most striking, though not new, message from these data is that HIV infection is the major driver of childhood mortality in these rural and urban communities. About 53% of infants who became infected would have died by 18 months compared with 4% of infants who were not. This again emphasizes the gains for child survival if effective PMTCT programming were achieved(24
In this population, replacement feeding of HIV-uninfected infants between 7 and 18 months, or those who were switched earlier, did not increase mortality compared to infants who continued to receive breastmilk. It is essential however, to contextualize these findings including the circumstances that guided the initial feeding choices of these mothers(14
) and the support available to them, before simple generalizations are drawn. Mothers who had limited access to safe water, poor sanitation at home, as well as higher CD4 counts tended to initiate breastfeeding; mothers with lower CD4 counts and access to personal income tended to start replacement feeds(14
). Mothers also received ongoing guidance and support in their feeding choice and had immediate access to study teams at clinics. The sum of these ‘interventions’ are likely to have optimized the environment in which these feeding choices were practised and reduced potential morbidity and mortality. This is evidenced by results of an operational study describing the South African national PMTCT programme(3
) in which infants of women who were given replacement feeds under inappropriate conditions experienced the highest risk of HIV transmission or death (AHR 3.63; 95%CI 1.48–8.89) in comparison to those who received replacement feeds under appropriate circumstances.
We were unable to determine if there had been changes in household circumstances from the antenatal period that might have influenced mothers’ decisions to switch from breastfeeding to non-breastfeeding in the postpartum period. Antenatal demographic and socio-economic characteristics were available, but although counsellors and nurses would have learned of changes in mothers’ circumstances and this would have influenced subsequent counselling, this information was not systematically captured in the database. All HIV-infected mothers had been counselled, both antenatally and postpartum, to stop breastfeeding around 6 months, as long as there was a safe and nutritionally adequate alternative. In spite of this, 688 (77%) mothers of infants uninfected at 6 months decided to continue breastfeeding. Amongst this group 22% would have continued to at least 18 months. For these infants, although at continued risk of HIV infection, this strategy might still have been correct to promote their long term overall survival. Given that this was not a randomized trial, we are unable to determine what might have happened if those same mothers had chosen to stop breastfeeding earlier and adopt a feeding practice that could not have been safely supported.
Continued breastfeeding resulted in significantly more infections over the 18 month period. Children who were breastfed for more than 6 months were 2.7 times more likely to become infected compared to infants who were breastfed for less than 6 months. The low risk of death, apart from HIV transmission, highlights the feasibility of supporting good infant feeding to promote child survival. HIV-free survival could be achieved, even in rural settings, if strategies to reduce the risk of postnatal infection such as HAART to breastfeeding mothers are demonstrated to be effective and feasible at scale.
In this study, amongst infants that never became infected, early feeding practices did not influence long term survival. As in previous analyses of this cohort(1
), numbers of infants in the mixed feeding categories in the first 6 months were too small to make statistical comparisons regarding transmission, including the risk of mixed feeding in the first 6 months versus the risk of receiving breastmilk and complementary feeds beyond 6 months. The overall estimated risk exposure for breastfeeding over the 18 month period (9.1 cases per 100 child-years of breastfeeding) was similar to previous estimates(26
). Among the infants breastfed beyond 6 months of age and allowing for maternal CD4 counts, although the differences in overall probability of HIV-free survival between 7–18 months did not reach statistical significance, those who were exclusively breastfed in the first 6 months tended to do better than those mixed-fed.
Maternal health remained a major determinant of HIV infections and mortality of exposed infants throughout the 18 month period. Overall, the probability of HIV infection or death was highest amongst infants born to mothers with low antenatal CD4 counts but also significantly higher if the mother was unemployed antenatally. Unemployment could represent several independent influences including dependency and lack of autonomy to make choices about infant feeding practices, impaired nutrition and lack of resources e.g. taxi fares to access to health services. Low birth-weight of exposed infants also increased the likelihood of adverse outcomes in early life and may similarly reflect poor maternal health and antenatal care. Perhaps surprisingly, infant outcomes between 7 and 18 months were more substantially determined by these maternal factors than by feeding practices.
We were surprised by the relatively large number of mothers who continued to breastfeed beyond 6 months, despite counselling, planning and access to replacement feeds. That so many mothers opted to continue breastfeeding likely reflects the socio-demographics of the study population and cultural issues within the communities. These mothers presumably weighed up the complexities and relative inconvenience of safe replacement feeding and decided that continued breastfeeding was still preferable. PMTCT programmes need to offer better counselling and support throughout this time if overall child health and survival are to improve.
Methodologically, we did not permit any lapses whatsoever when allocating infants to specific feeding practices. If an infant received water, non-human milk or solids even for one day, the infant was reclassified as mixed feeding. In comparison with our analysis of HIV transmission in the first 6 months(1
), in which we permitted up to 3 lapsed days before exclusion to another category, this approach significantly reduced the number of infants within the exclusive breastfeeding group. Also, because in this analysis we were interested in transmission and survival by initial feeding mode, or feeding mode up to a certain age, we did not censor when the child dropped out of the initial feeding mode.
The question remains how best to identify and support the optimal infant feeding strategy beyond 6 months for individual HIV-infected women. Any approach must consider a mother’s prevailing or changing household circumstances as well as her own disease status, to determine if, or when she should stop breastfeeding. Programmes need to remain in contact with mothers to assist with the process of stopping breastfeeding and offer advice on complementary feeding. Amidst the many difficult contextual issues remains the greatest opportunity, namely to identify the women with low CD4 counts and start them on HAART for life. Where HAART is not available for this group of women, the balance of evidence suggests that where possible and safe, stopping breastfeeding at 6 months or before will increase the child’s long term prospects of survival. The ability of international recommendations, national policies, individual programmes and community responses to promote and protect the equality and autonomy of women and mothers, to benefit from employment and access to health interventions, will be measured by the most tangible of child health outcomes, namely whether they live or die.