After the United States' recent opposition to a World Health Organization (WHO) resolution promoting breastfeeding, U.S. president Donald Trump said that infant formula was needed especially for women in resource-poor situations. However, that's exactly when breastfeeding is safer than formula, Michele Barry, M.D., FACP, of the Stanford School of Medicine, argued in a New York Times article on this controversy.
This difference in breastfeeding stances is also reflected in current guidelines for women living with HIV. WHO currently recommends exclusively breastfeeding for at least six months and continuing to breastfeed until the child is 12-24 months old. The mother -- and, if appropriate, the infant -- should be on antiretroviral treatment during that time. "The guideline is intended mainly for countries with high HIV prevalence and settings in which diarrhea, pneumonia, and undernutrition are common causes of infant and child mortality," WHO notes.
The U.S. Centers for Disease Control and Prevention (CDC)'s asks on its breastfeeding page, "Is it safe for a mother infected with HIV to breastfeed her infant?" and answers with an unqualified "No." This holds true regardless of the mother's viral load, the CDC says.
However, according to a Viewpoint published by Catriona Waitt, Ph.D., et al. in The Lancet HIV, recent research showing that a person living with HIV who is on antiretroviral treatment and whose viral load is undetectable will not transmit the virus to his or her sexual partners also ought to be considered. Waitt works at the University of Liverpool, and her coauthors are from various institutions in Europe and Canada.
The Lancet Viewpoint notes that the risk of transmitting HIV through the breastmilk of virally suppressed women in high-income countries is not known because randomized trials on this issue are not feasible there.
"The main reason why such trials could not be done in high income countries is that guidelines universally prohibited breastfeeding (to the extent that in some countries, the choice to breastfeed was seen as a child protection issue)," Waitt explained to TheBodyPRO. The Viewpoint notes that studies in southern Africa, such as the PROMISE trial, have shown very low transmission rates during breastfeeding when the mother was on successful antiretroviral therapy (0.3% when the infant was breastfed for six months, 0.7% after 12 months). Such studies have also found a difference in the amount of virus in the mother's blood and in her breastmilk, but few participants were long-term virally suppressed. It is therefore unclear to what extent these results apply to women with sustained undetectable viral loads.
As with all medications, antiretrovirals may transfer to the infant via breastmilk. What evidence exists comes from low- and middle-income countries, where older HIV drugs are more common. There is little data on the newer drugs used in high-resource settings. "Although the Antiretroviral Pregnancy Registry is well established, no parallel system exists to collect data relating to clinical outcomes, growth, and development in breastfed infants," the authors of the Lancet Viewpoint note.
Another unresolved issue is infant prophylaxis if the mother has an undetectable viral load. National guidelines in high-income countries range from no prophylaxis in Switzerland to at least six weeks of zidovudine (AZT, Retrovir) and/or nevirapine (Viramune) in the U.S. Recommendations also differ on the frequency of virological monitoring for both mother and baby. While too many required visits with a health care provider could prove burdensome to a new parent, such monitoring could be integrated into infant checkups or home visits, which are common in high-resource countries, Waitt said. "But this would need development of an integrated model and training of these health care providers, and so forth," she cautioned. Home visits may also be problematic if relatives are present to whom the mother has not disclosed her HIV status, she added.
Having a newborn in the house can be exhausting, even without any medical issues. Reviews of studies in both low- and high-income countries have found that new mothers' treatment adherence and retention in care can suffer once the baby is born. As a result, women's viral loads may become detectable while they are breastfeeding. At that point, breastfeeding should be stopped if safe alternatives are available. However, abrupt weaning can be difficult. Anecdotal evidence suggests that some women may report they have stopped breastfeeding when this is not the case, the Viewpoint notes.
While high-resources countries generally offer newer medications and safer infant formula options, this may not necessarily apply to all women living in them. Much depends on health care access, Waitt noted. "It would be hoped that in a well-resourced setting, all women, irrespective of background, can access frequent clinical follow-up and virological monitoring." However, this may not always be the case, she added, and advocated for qualitative research to determine whether different models of care are needed for different subgroups of women.
To resolve these and other questions, the Viewpoint authors propose several research priorities, including:
- Determine whether the cell-associated virus in breastmilk is related to HIV transmission even in mothers who are long-term virally suppressed and are taking newer antiretrovirals.
- Establish two registries in high-income countries: one to generate data on HIV transmissions via breastfeeding and the other to capture the long-term effects of infants' breastmilk exposure to the mother's antiretrovirals.
- Determine the pharmacokinetics of newer HIV medications in breastmilk and generate monitoring data on the treatment regimens that are more common in high-resource settings.
- Establish an expert network that includes patients to share data on women living with HIV who are breastfeeding in high-income settings.
- Include social science research to develop data on the best models of appropriate care.