Transmission of CMV, HTLV-1, and HIV through breastmilk

Abstract

Breastfeeding is a critical child survival intervention. The potential for transmission of some viral infections from mother-to-child, however, presents the dilemma of how best to interpret the benefits and risks of breastfeeding in different settings. Here, we compare the transmission dynamics, risk factors and outcomes of infection with three chronic viruses transmitted through breast milk: cytomegalovirus (CMV), human T-cell lymphotropic virus type 1 (HTLV-1), and human immunodeficiency virus (HIV). We provide an overview of current intervention approaches and discuss scientific, policy and programming gaps in our understanding of these major global infections. Key messages: • Three viruses are known to be transmitted through breastfeeding and to result in chronic infection: CMV, HTLV-1 and HIV. • CMV transmission through breast milk mostly leads to subclinical infection, except in preterm infants in whom severe clinical disease can occur; the best preventive and treatment approaches in this group remain unclear and more data are needed on long-term sequelae. • HTLV-1 is restricted to specific geographic foci and can be transmitted from mother-to-child through breastfeeding in 10-25% of cases; the best preventive strategy is avoidance or shortening of breastfeeding where safe alternatives are available. • The absolute transmission risk of HIV through breastfeeding in the context of suppressive maternal antiretroviral therapy is now low, even over extended periods. • Guidance for infant feeding for women living with HIV varies by setting: in low-and middle-income countries, breastfeeding with suppressive ART and adherence support is recommended, while in high-income settings formula feeding is advised.

Human Cytomegalovirus Reactivation During Lactation: Impact of Antibody Kinetics and Neutralization in Blood and Breast Milk

“…The mechanism of postnatal HCMV-reactivation in the mammary gland without viral systemic infection (DNAemia) is still unknown. Virus-shedding into breast milk of immunocompetent healthy breastfeeding mothers occurs in nearly every seropositive mother at any time point during lactation, but usually ends 2-3 months after birth [3,4]. Transmission via breastfeeding can lead to severe symptomatic HCMV-infection in preterm infants, with increased risk with birth weight below 1500 g or less than 32 weeks of gestational age [2].…”

“…Colostrum (up to one week postpartum (pp)) is considered especially important for newborns. Colostrum is followed by transient milk (2)(3)(4) weeks pp) and mature milk (more than 4 weeks pp). The World Health Organization (WHO) recommends exclusive breastfeeding for the first six months of life [10].…”

Estimating the Risk of Human Herpesvirus 6 and Cytomegalovirus Transmission to Ugandan Infants from Viral Shedding in Saliva by Household Contacts

“…Because of the public health importance of HHV-6 and CMV infections and the interest in preventing HHV-6-related diseases, understanding the determinants of transmission is of great interest. CMV transmission to infants has been shown to occur most commonly via breast milk, though saliva and urine are other routes of infection during early childhood [9,[20][21][22][23]. HHV-6 is likely transmitted through saliva, based on the frequency of the viral detection of the virus in the saliva of infected individuals [3]; in contrast, HHV-6 infection is not associated with breastfeeding and is rarely found in breast milk [9,24].…”

A Nationwide Antenatal Human T-Cell Leukemia Virus Type-1 Antibody Screening in Japan

“…Several risk factors for HTLV-1 MTCT other than longterm breastfeeding are known, including high mother HTLV-1 antibody titers and PVL (Ureta-Vidal et al, 1999;Hisada et al, 2002;Paiva et al, 2018). Paiva et al (2018) reported that breastfeeding ≥12 months, higher maternal PVL (≥ 100 copies/10 4 PBMC) and ≥ 2 previous HTLV-1-infected children were independently associated with MTCT in a multiple logistic regression. Hisada et al (2002) suggests that mothers who have a high PVL (≥ 3%) should be encouraged not to breast-feed, while a risk of the transmission in low PVL less than 0.1% was negligible.…”

“…The potential for viral transmission from mother to child presents a dilemma on how best to interpret the benefits and risks of breastfeeding in different settings (Prendergast et al, 2019). Meta-analysis has shown that feeding with the mother's own milk or banked human milk can reduce the risk of necrotizing enterocolitis and/or severe infections, especially for very lowbirth-weight infants (<1,500 g birth weight) or very preterm infants (<32 weeks of gestation) (Corpeleijn et al, 2016;Miller et al, 2018).…”