WWR: New Research into Breastfeeding and HIV

This week we’re reading about research into breastfeeding, one of the ways that HIV can be transmitted from mother to child.

Despite the transmission risks, did you know that an infant who breastfeeds from an HIV-positive mother has an 85% chance of NOT becoming infected with HIV, even in the absence of any anti-HIV drug treatment?

In fact, from before birth to the postnatal breastfeeding period, 60% of babies born to HIV-positive mothers will remain HIV-free, even without antiretroviral drugs given to the mom or baby.

But what is protecting these infants from contracting HIV?

Dr. Laura Guay spoke this week with VAX, the Bulletin on AIDS Vaccine Research, about a new study that seeks to answer this important question.

The study was led by researchers from the University of California, San Diego, and included Dr. Grace Aldrovandi from Children’s Hospital, Los Angeles – a former Elizabeth Glaser Scientist Award recipient.

The team has begun to address ways in which breast milk itself may hold the keys for this protection.

The researchers compared breast milk samples from HIV-transmitting and non-transmitting mothers. The samples came from a subset of a large cohort of mother-infant pairs in Zambia known as the Zambian Exclusive Breastfeeding Study, or ZEBS.

The authors found that compounds known as human milk oligosaccharides (HMOs) may play a critical role in both transmitting and non-transmitting mothers. Oligosaccharides are complex carbohydrates (think sugars) that are abundant components of breast milk, but whose functions are poorly understood.

In the study, the presence of a particular type of HMO was found to reduce the risk of transmission of HIV to the breastfeeding infant by  nearly half – an amazing result. The sugars might actually block HIV from attaching to the infant’s cells and being transported to sites of infection. Further work will be necessary to translate these findings into potential therapies to prevent HIV transmission.

Despite these results, you might wonder why mothers might choose to breastfeed at all if there is a risk of transmitting HIV.

The answer is that in areas of the world where clean water for replacement feeding does not exist, infants who do not breastfeed have a significant risk of dying from malnutrition or diarrheal diseases. In addition, breast milk provides critical nutrition to the infant that cannot be matched by formula or other replacement feeding methods.

In these situations, breastfeeding is recommended for HIV-positive women by the World Health Organization, with appropriate antiretroviral therapy to mother and baby to reduce the risk of transmission.

Clearly anything we can do to enhance the safety of breastfeeding by HIV-positive women is highly warranted.

Here at the Elizabeth Glaser Pediatric AIDS Foundation, we have sponsored and conducted research to help us understand both the reasons for HIV breast milk transmission and ways to block it – as well as the feeding practices of women in our country programs.

For example, additional studies by Dr. Aldrovandi and funded by the Foundation have investigated how the presence of maternal anti-HIV antibodies in breast milk may influence transmission.

Other Foundation-funded studies by Dr. Ed Janoff at the University of Colorado have addressed how the introduction of mixed feeding (breast milk and solid foods) may cause damage to the infant gut and potentially increase the risks of HIV transmission.

Our own research into feeding practices and infant nutrition in Lesotho and Rwanda will help us understand how to make breastfeeding safer for both the mother and infant in resource-limited settings.

These results and further research to address why the majority of HIV-exposed infants don’t get infected may speed us toward the goal of a vaccine – and the ultimate elimination of pediatric HIV.

Read the articles below to learn more about this week’s study:

Jeff Safrit, Ph.D., is EGPAF's Director of Clinical and Basic Research, and is based in Los Angeles, CA.