Q+A: Preventing Mother-to-Baby HIV Transmission

A mother with her baby in Blantyre, Malawi. (UK Department for International Development)

The National Institutes of Health released findings this week that said HIV therapy for breastfeeding mothers can virtually eliminate transmission to their babies, according to results from a large clinical trial conducted in sub-Saharan Africa.

The results are from the ongoing Promoting Maternal and Infant Survival Everywhere (PROMISE) study, and confirm the “benefits of antiretroviral therapy for every person living with HIV,” said NIAID Director Anthony Fauci, MD.

Florence Momplaisir, MD, an assistant professor in the College of Medicine, is an infectious disease specialist with particular interest in linking HIV-infected mothers with care. A 2015 study from Momplaisir and the Philadelphia Department of Health showed that just 38 percent of new moms in Philadelphia with HIV are still receiving treatment for the disease three months after delivery.

Momplaisir answered six questions about what the results of the PROMISE study mean for the fight against HIV in the United States and abroad.

What is the PROMISE study and what is its significance?
The PROMISE study is a clinical trial conducted in Africa and India by the International Maternal Pediatric Adolescent AIDS Clinical Trials network. It is funded by the National Institutes of Health. The study aims to understand how best to reduce the risk of HIV transmission from infected pregnant women to their babies during pregnancy and postpartum while preserving the health of mothers and their children.

This latest study found that taking a three-drug antiretroviral regimen during breastfeeding would eliminate HIV transmission by breast milk to their infants. But aren’t there other ways that mothers could transmit HIV to their babies before they are born?
Absolutely. HIV can be transmitted from mother to baby in utero, particularly for mothers who acquire the virus during pregnancy. These women are at increased risk of transmitting the infection to their baby because the virus replicates in high numbers during acute infection. The risk of HIV transmission also increases at delivery when blood mixing occurs that’s why giving the baby HIV prophylaxis with antiretrovirals is important.

PROMISE had several components embedded in the study and evaluated maternal and infant maternal prevention strategies separately during pregnancy through 14 days postpartum, breastfeeding and after HIV maternal transmission risk is over. The data presented here pertains to women in the breastfeeding period. However, we know from this trial and others that women receiving triple therapy (three antiretrovirals) are much less likely to transmit the infection to their baby.

If a mother receives antiretroviral therapy during pregnancy, does she need to continue to receive it after giving birth?
Yes. The World Health Organization and U.S. guidelines recommend that mothers continue antiretroviral therapy during and after pregnancy to preserve maternal immune function and also decrease the risk of non-AIDS complications (dementia, cardiovascular events and malignancies for example) that can occur when people are not on HIV treatment. PROMISE found that the risk of mother-to-child transmission to be very low (0.6 percent at one year postpartum) when women are on triple therapy and breastfeeding, so there is an obvious benefit to the baby. The risk of HIV transmission when women are not on antiretrovirals can be up to 30 percent.

What are the implications of this study and its findings?
Prior observational data from Africa had shown that the risk of mother-to-child transmission via breast milk is low when women are on triple therapy and breastfeeding, but PROMISE is the first randomized control trial to establish the evidence. These results have strong implications in low- and middle-income countries where breastfeeding protects children from death related to diarrheal diseases, because access to clean water is scarce. Breastfeeding also protects children from malnutrition and other infectious complications. Infant survival in PROMISE was very high at 99 percent.

WHO recommends that mothers who are infected with HIV continue to breastfeed if they are taking antiretrovirals. Do you think this is an appropriate recommendation?
In low to middle income counties, the benefits of the WHO recommendations are clear, because the risk of infant mortality without breastfeeding is high. In resource rich countries, the benefits of breastfeeding for women living with HIV mostly relate to mother-infant bonding and the infant receiving maternal antibodies via breastmilk. Some data suggests that infants who are breastfed are less likely to develop obesity, so there might be additional benefits.

The results from PROMISE are encouraging, but I would caution against breastfeeding in the U.S. until the U.S. guidelines change, keeping in mind that these recommendations would only apply to women who maintain viral suppression during pregnancy and postpartum. I do think that based on the less than one percent risk of mother-to-child transmission of HIV found in PROMISE, pregnant and postpartum women who are adherent to HIV therapy should have a conversation with their provider. They should discuss the risk and benefits of breastfeeding, and HIV and obstetrical providers should be open to having that conversation.

What are the barriers HIV-infected mothers face that prevent them from receiving appropriate care?
There are multiple barriers that women face personally, in their community and within the health system that prevent them from receiving appropriate care. Stigma — both internalized and externalized — unfortunately is a common barrier. Postpartum, women often prioritize taking care of their baby and their health takes a back seat, including going to their HIV postpartum appointments. Our health care system needs to be better integrated to effectively care for HIV infected women and HIV-exposed infants.

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