The campaign, “Undetectable=Untransmittable” or “U=U,” meant that people infected with HIV with an undetectable viral load (or <200 copies/mL) could not transmit the virus to their partners.1 Now women with HIV are reconsidering this mantra for a new purpose: to breastfeed their infants with direction from their clinicians and newly revised guidelines.2
“The new guidelines in both Europe and North America are clear that HIV-positive women should be given evidence-based information to help them make their decision, and that those mothers who make the choice to breastfeed should be supported,” said Catriona Waitt, PhD, from the department of molecular and clinical pharmacology at the University of Liverpool in the United Kingdom, in an interview with Infectious Disease Advisor.
“This is different from actively encouraging and promoting breastfeeding in this group of mothers at the current time, and it should be made clear to them that there remain some unanswered questions. Whilst the risk of transmission from a mother who is virologically suppressed and adherent to antiretroviral therapy (ART) is clearly very low, we cannot yet say with certainty [that] it is zero,” continued Dr Waitt.
Why the Thinking Has Changed
In low-income countries, women with HIV with an undetectable viral load were advised to breastfeed their infants because they did not have access to safe water and affordable formula.3 Women in high-income countries, however, were discouraged from doing so because there may still a possibility of transmitting the virus to the infant via breast milk.3,4
Studies conducted almost a decade ago in low-income countries, such as the Breastfeeding, Antiretrovirals, and Nutrition trial, reported a low 1.7% (95% CI, 1.0-2.9) risk for HIV transmission in infants (N=2369 mother-infant pairs) who received an antiretroviral agent (nevirapine) during breastfeeding (P <.001).5 At 6 months postpartum, the HIV incidence in infants whose mothers received ART was 2.9% (95% CI, 1.9-4.4) and 5.7% (95% CI, 4.1-8.0) in infants in the control group.5
More recently, the Promoting Maternal and Infant Survival Everywhere (PROMISE) study (N=2431 mother-infant pairs) demonstrated that with maternal or infant ARV transmission rates during breastfeeding at 6, 9, and 12 months were as low as 0.3% (95% CI, .1-.6), 0.5% (95% CI, .2-.8), and 0.6% (95% CI, .4-1.1), respectively, with no significant difference between study arms.6 The 14-site multinational trial included mothers whose CD4+ count was ≥350 cells/mm3, depending on the specific country’s ART threshold.6
Advocates say that women with undetectable viral loads should be able to breastfeed after thorough consultation with their clinicians.2 The European AIDS Clinical Society — and less enthusiastically, the American HIV perinatal transmission prevention guidelines — have recognized the need to support women with HIV who want to breastfeed if their viral load has been consistently undetectable.2,4,7
Women with HIV who wish to breastfeed should receive as much information as possible about the risk and the current evidence base, including:3
- When to wean and the option to use banked breast milk
- What is known about infant exposure to maternal ARV via breast milk
- The importance of exclusive breastfeeding and the dangers of mixed feeding
- Infant ARV prophylaxis
- Regular testing for mother and infant
“There remain some groups of women, however, in whom breastfeeding should be discouraged. The main concerns are for those who are not virologically suppressed, who have a history of frequent virological ‘blips,’ or who are known to have struggles maintaining adherence, perhaps due to lifestyle factors,” cautioned Dr Waitt.
Mixed Feeding Raises HIV Transmission Risk
Clinicians acknowledge that by discouraging women with HIV from breastfeeding, they may be tempted to intermittently breastfeed their infants to conform to familial and social pressures.3 Mixed feeding — alternating between breast milk and formula — paradoxically doubles the risk for an infant in contrast to exclusive breastfeeding because the HIV viral load in breast milk may peak when breastfeeding is interrupted.3,7 A protein found in breast milk, tenascin C, inhibits HIV virions from binding to cells, which further protects the infant.3
The US recommendations on perinatal HIV transmission emphatically state that women with HIV should avoid breastfeeding to prevent mother-to-child transmission of HIV because the risk is not zero.4 The recommendations, however, suggest monitoring maternal plasma viral loads every 1 to 2 months for the duration of breastfeeding and to contact an HIV expert if the mother’s viral load becomes detectable.4
In infants, the US guidelines recommend testing every 3 months during breastfeeding and 4 to 6 weeks, 3 months, and 6 months following the end of breastfeeding.4 The guidelines also stress the importance of reporting mastitis and infant thrush because these conditions may signal an infection and lead to HIV shedding.3,4
The evidence base lacks rescue strategies should the mother’s or infant’s viral load become detectable.2 The American guidelines recommend that HIV transmitted to the infant be treated with a full combination ARV regimen.4
Indeed, the decision to breastfeed in women with HIV is a nuanced one. Judy Levison, MPH, MD, professor of obstetrics and gynecology at Baylor College of Medicine in Houston, Texas, admitted that although the risk for HIV transmission during breastfeeding is low when mothers and infants are on ARV, “there’s still so much we do not know. There are cases of women with undetectable viral loads having transmitted HIV to their infants.”
Summary and Clinical Applicability
In low-income countries, women with HIV with an undetectable viral load were advised to breastfeed their infants because they did not have access to safe water and affordable formula. Women in high-income countries, however, were discouraged from doing so. Now advocates say, with caveats, that women with undetectable viral loads should be able to breastfeed.
- Prevention Access Campaign. Risk of sexual transmission of HIV from a person living with HIV who has an undetectable viral load: messaging primer & consensus statement. www.preventionaccess.org/consensus Accessed July 22, 2018.
- Waitt C, Low N, Van de Perre P, Lyons F, Loutfy M, Aebi-Popp K. Does U=U for breastfeeding mothers and infants? Breastfeeding by mothers on effective treatment for HIV infection in high-income settings [published online June 27, 2018]. Lancet HIV. doi:10.1016/S2352-3018(18)30098-5
- Levison J, Weber S, Cohan D. Breastfeeding and HIV-infected women in the United States: harm reduction counseling strategies. Clin Infect Dis. 2014;59(2):304-309. doi:10.1093/cid/ciu272
- Panel on Treatment of Pregnant Women with HIV Infection and Prevention of Perinatal Transmission. Recommendations for use of antiretroviral drugs in transmission in the United States. http://aidsinfo.nih.gov/contentfiles/lvguidelines/PerinatalGL.pdf Accessed July 3, 2018.
- Chasela CS, Hudgens MG, Jamieson DJ, et al. Maternal or infant antiretroviral drugs to reduce HIV-1 transmission. N Engl J Med. 2010;362(24):2271-2281. doi:10.1056/NEJMoa0911486
- Flynn PM, Taha TE, Cababasay M, et al. Prevention of HIV-1 transmission through breastfeeding: efficacy and safety of maternal antiretroviral therapy versus infant nevirapine prophylaxis for duration of breastfeeding in HIV-1-infected women with high CD4 cell count (IMPAACT PROMISE): a randomized, open-label, clinical trial. J Acquir Immune Defic Syndr. 2018;77(4):383-392. doi:10.1097/QAI.0000000000001612
- Johnson G, Levison J, Malek J. Should providers discuss breastfeeding with women living with HIV in high-income countries? An ethical analysis. Clin Infect Dis. 2016;63(10):1368-1372. doi:10.1093/cid/ciw587