Where science and public health do not intersect.

From a recently published article in the always excellent British medical journal Lancet:

“Infants who were breastfed but also received solids (generally home-prepared cereal or commercial infant porridges) any time after birth, were nearly 11 times more likely to acquire [HIV] infection than were exclusively breastfed children.”

Coovadia HM et al. Mother-to-child transmission of HIV-1 infection during exclusive breastfeeding: the first six months of life. Lancet 2007 [in press].

///

This article was written by Coovadia et al, a group based right here in Durban at the Nelson Mandela School of Medicine. This highly-relevant issue of whether children of HIV-infected mothers should or should not breastfeed is very interesting one both from a scientific and a public health standpoint.

It is counterintuitive for many (including myself) to imagine that an HIV-negative baby should be fed the virus-containing milk of its mother. Breastfeeding is well demonstrated to protect against a range of illness, but it is risky because of the opportunity for HIV transmission from an infected mother to her baby. However, the data from this extensive study shows that if the infant is fed EXCLUSIVELY breastmilk - and does not have any formula or other solid food - for the first 6 months of life, the practice of breastfeeding is very safe and greatly reduces the probability that the baby will become HIV-positive. The underlying science of this has to do with the fact that babies' digestive systems are unable to handle most other foods at this early developmental stage, leading to small lesions or gaps in the GI mucosa which leads to increased transmission of the virus when the baby consumes breast milk with a positive viral load.

However, the public health policies that will emerge from this finding are ambiguous at best. Working mothers, especially in the developing world, can't always make time to feed their babies on regular schedules. These women tend to work long shifts, travel great distances between home and work using public transportation, and often rely on other family members to help provide care for their children. Complicating this matter even further, baby formula is prohibitively expensive. The end result is that it is most convenient for mothers to feed their infants a mixture of breast milk along with other available foods in these resource-limited settings, dramatically increasing the likelihood that the child will become positive within the first six months of life.

Stopping the spread of HIV from mother to child is exceedingly important (for a whole host of reasons that I shouldn’t get into here), yet how can South Africa or the World Health Organization advise mothers in impoverished settings around the world to do what is essentially impossible? While the science underlying this paper is very strong, it is far less obvious to me – as well as to other members of the HIV/AIDS research community – what public health guidelines should arise from these findings.