Got bile? Breastmilk bile acids influence norovirus infection.

Breastfeeding provides infection protection for several pathogens but not for noroviruses. Mechanisms explaining this discrepancy have been unclear. In this issue of Cell Host & Microbe, Peiper et al. demonstrate that while breastmilk protects mice from intestinal damage, it promotes neonatal murine norovirus infection due to maternal-derived bile acids.1.

Neutralizing antibodies in milk and blood of lactating women vaccinated for SARS-CoV-2: a systematic review.

OBJECTIVE: To compare the presence of neutralizing antibodies against SARS-CoV-2 found in the breast milk and blood of vaccinated lactating women with those not vaccinated. DATA SOURCE: The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) under CRD42021287554 and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Cohort, case-control, and cross-sectional studies that evaluated antibodies against SARS-CoV-2 in the milk and blood of vaccinated mothers and had as control group unvaccinated mothers were eligible. Health Sciences Descriptors (DeCs), Medical Subject Headings (MeSH) and Emtree descriptors were used for the Virtual Health Library (VHL), Medical Literature Analysis and Retrieval System Online (Medline/Pubmed), and Embase databases, respectively. In the Web of Science and Scopus, the strategy was adapted. No restrictions on the publication period and language were set. DATA SYNTHESIS: The search identified 233 records, of which 128 duplicates and 101 papers that did not meet the inclusion criteria were excluded. Hence, four cohort studies were eligible. Nursing mothers vaccinated with the Pfizer-BioNTech and Moderna vaccines showed antibodies against SARS-CoV-2 in their blood and breast milk. CONCLUSIONS: Vaccinated lactating women had higher levels of immunoglobulin G (IgG) and A (IgA) in serum and breast milk than unvaccinated women.

Breast milk induces the differentiation of monocytes into macrophages, promoting human cytomegalovirus infection.

Human cytomegalovirus (HCMV) is a ubiquitous herpesvirus found in human breast milk that is frequently transmitted from HCMV-seropositive mothers to their infants during the postnatal period. Despite extensive research, the mechanisms underlying HCMV transmission from breast milk and the anatomical location at which virus transfer takes place remain unclear. Breast milk contains many uniquely differentiated macrophages that undergo specific morphological and functional modifications in the mammary gland during lactation. Although the existence of permissive HCMV infection in differentiated macrophages has been well-described, the role of breast milk in this process remains unknown. Herein, we report that exposure of isolated peripheral blood monocytes to breast milk induces their differentiation into macrophages that exhibit an M2 phenotype (CD14highCD163highCD68highCD206high) and promotes a productive and sustained HCMV infection. We also found that breast milk triggers macrophage proliferation and thus sustains a unique population of proliferating, long-lived, and HCMV-susceptible macrophages that are capable of ongoing production of infectious virions. These results suggest a mechanism that explains chronic HCMV shedding into the breast milk of postpartum seropositive mothers. We also found that HCMV virions released from breast milk-induced macrophages generate a productive infection in primary infant tonsil epithelial cells. Collectively, our results suggest that breast milk may facilitate HCMV transmission from mother to infant via the oropharyngeal mucosa. IMPORTANCE: While human cytomegalovirus (HCMV) is frequently detected in the breast milk of HCMV-seropositive women and is often transmitted to infants via breastfeeding, the mechanisms by which this transmission occurs remain unclear. In this study, we modeled HCMV transmission at the oropharyngeal mucosa. We treated human monocytes with breast milk to mimic the lactating mammary gland microenvironment. We found that monocytes differentiated into macrophages with an M2 phenotype, which were highly permissive for HCMV. We also discovered that breast milk induces macrophage proliferation. Thus, exposure to breast milk increased the number of HCMV-susceptible macrophages and supported high levels of infectious HCMV. We found that HCMV virions released from breast milk-induced macrophages could infect primary infant tonsil epithelial cells. Collectively, these findings reveal the dual role of breast milk that induces the differentiation and proliferation of macrophages in the mammary gland and thus facilitates mother-to-child HCMV transmission at the oropharyngeal mucosa.

Postnatally acquired cytomegalovirus infection among preterm infants.

PURPOSE OF REVIEW: Although there are multiple benefits of mother's own milk feeding for very-low birth weight, low gestation infants, those born to cytomegalovirus (CMV)-seropositive mothers are at risk for acquiring postnatal CMV infection. This review will describe the risk and consequences of postnatal CMV infection among very preterm infants. RECENT FINDINGS: Postnatal CMV may manifest as clinically silent infection or as mild to severe and occasionally fatal disease. The risk of disease is balanced by the health benefits of human milk feeding to preterm infants. Postnatal CMV infection has been associated with increased risks of multiple preterm morbidities such as bronchopulmonary dysplasia, necrotizing enterocolitis and neurodevelopmental impairment, but current evidence is limited by the selection bias inherent to reporting in case series and retrospective cohort studies. SUMMARY: Knowledge gaps exist regarding the risk-benefit balance of pasteurization to inactivate CMV in fresh breast milk, as well as the optimal dosing, duration and efficacy of treating infected infants with antiviral medications. Multicenter, prospective studies are urgently needed to accurately determine the true burden that postnatal CMV infection presents to very preterm infants. Such studies will inform the need for preventive strategies and treatment guidance.

Metabolic immaturity and breastmilk bile acid metabolites are central determinants of heightened newborn vulnerability to norovirus diarrhea.

The pathogenic outcome of enteric virus infections is governed by a complex interplay between the virus, intestinal microbiota, and host immune factors, with metabolites serving as a key mediator. Noroviruses bind bile acid metabolites, which are produced by the host and then modified by commensal bacteria. Paradoxically, bile acids can have both proviral and antiviral roles during norovirus infections. Working in an infant mouse model of norovirus infection, we demonstrate that microbiota and their bile acid metabolites protect from norovirus diarrhea, whereas host bile acids promote disease. We also find that maternal bile acid metabolism determines the susceptibility of newborn mice to norovirus diarrhea during breastfeeding. Finally, targeting maternal and neonatal bile acid metabolism can protect newborn mice from norovirus disease. In summary, neonatal metabolic immaturity and breastmilk bile acids are central determinants of heightened newborn vulnerability to norovirus disease.

Rapid detection of human cytomegalovirus by multienzyme isothermal rapid amplification and lateral flow dipsticks.

Introduction: Human cytomegalovirus (HCMV) is the most common viral infection seen in newborns. The major route of transmission for acquired human cytomegalovirus infection is breast milk from mothers who are HCMV seropositive to the infants. Thus, a rapid, economical, and simple method to perform HCMV test in breast milk is crucial and necessary for preventing acquired HCMV infection, especially in underdeveloped regions with limited laboratory resources. Methods: In this study, an effective technique for the detection of HCMV was constructed by combining multienzyme isothermal rapid amplification (MIRA) and lateral flow chromatography strip (LFD). Primers for the conserved HCMV sequence UL83 were utilized for MIRA-LFD testing. Results: Our results showed that the entire MIRA reaction could be completed in 12 minutes at 37°C, and LFD outcomes could be observed visibly after 10 minutes. The detection sensitivity of this method reached 50 copy/µl. Samples of breast milk were examined to compare MIRA-LFD and conventional qPCR. The accuracy of MIRA-LFD was 100%. Discussion: The straightforward, rapid, economic features of the test can provide the significant advantages for the prevention of breast milk-acquired cytomegalovirus infection, particularly in resource-limited locations with high seroprevalence of cytomegalovirus.

Human cytomegalovirus in breast milk is associated with milk composition and the infant gut microbiome and growth.

Human cytomegalovirus (CMV) is a highly prevalent herpesvirus that is often transmitted to the neonate via breast milk. Postnatal CMV transmission can have negative health consequences for preterm and immunocompromised infants, but any effects on healthy term infants are thought to be benign. Furthermore, the impact of CMV on the composition of the hundreds of bioactive factors in human milk has not been tested. Here, we utilize a cohort of exclusively breastfeeding full-term mother-infant pairs to test for differences in the milk transcriptome and metabolome associated with CMV, and the impact of CMV in breast milk on the infant gut microbiome and infant growth. We find upregulation of the indoleamine 2,3-dioxygenase (IDO) tryptophan-to-kynurenine metabolic pathway in CMV+ milk samples, and that CMV+ milk is associated with decreased Bifidobacterium in the infant gut. Our data indicate two opposing CMV-associated effects on infant growth; with kynurenine positively correlated, and CMV viral load negatively correlated, with infant weight-for-length at 1 month of age. These results suggest CMV transmission, CMV-related changes in milk composition, or both may be modulators of full-term infant development.

Specific IgA, But Not IgG, in Human Milk From COVID-19-Infected Mothers Neutralizes SARS-CoV-2.

This study highlights the importance of human milk in providing anti-severe acute respiratory syndrome coronavirus 2 immunity to newborns. The highest protective activity of human milk against COVID-19 was found in colostrum from infected mothers. Neutralizing activity was associated with high levels of specific IgA. Depletion of IgA, but not IgG, from milk samples completely abolished the ability of human milk to neutralize severe acute respiratory syndrome coronavirus 2.

Breastfeeding in the United States Among Women With HIV: Con Viewpoint.

To breast feed or not has long been a difficult question for women with human immunodeficiency virus (HIV) in high-income countries, as undetectable HIV in maternal plasma does not translate to zero risk of transmission while breastfeeding, and clean water and formula are readily available. Recent, and more permissive, changes in US and other high-income-country guidelines regarding breastfeeding underscore this issue and acknowledge the information gaps that are essential for informed maternal choice and provider management. These include lack of guidance as to routine monitoring of mothers during lactation, type and length of prophylaxis for infants, and lack of data on factors associated with increased breast-milk viral load and risk of transmission. Ancillary to data are the education and staffing needs for providers participating in the management of breastfeeding individuals. Future studies of breast-milk transmission will need to evaluate these gaps so that we can move transmission to zero.

In Support of Breast-/Chestfeeding by People With HIV in High-Income Settings.

Given that HIV can be transmitted through breastfeeding, historically, breastfeeding among women with HIV in the US and other resource-rich settings was discouraged. Formula feeding was the mandated feeding option out of concern for breast-milk transmission of HIV, which occurred in 16-24% of cases pre-antiretroviral therapy (pre-ART) use. In January 2023, the US Department of Health and Human Services' Perinatal Guidelines were revised to support shared decision-making for infant feeding choices. Updated clinical trials' data from resource-limited settings suggest the actual breastmilk HIV transmission rate in the context of maternal ART or neonatal postexposure prophylaxis is 0.3-1%. High-income countries are reporting more people with HIV breastfeeding their infants without cases of HIV transmission. We present the reasons for fully embracing breast-/chestfeeding as a viable, safe infant feeding option for HIV-exposed infants in high-income settings, while acknowledging unanswered questions and the need to continually craft more nuanced clinical guidance.

Understanding Viral and Immune Interplay During Vertical Transmission of HIV: Implications for Cure.

Despite the significant progress that has been made to eliminate vertical HIV infection, more than 150,000 children were infected with HIV in 2019, emphasizing the continued need for sustainable HIV treatment strategies and ideally a cure for children. Mother-to-child-transmission (MTCT) remains the most important route of pediatric HIV acquisition and, in absence of prevention measures, transmission rates range from 15% to 45% via three distinct routes: in utero, intrapartum, and in the postnatal period through breastfeeding. The exact mechanisms and biological basis of these different routes of transmission are not yet fully understood. Some infants escape infection despite significant virus exposure, while others do not, suggesting possible maternal or fetal immune protective factors including the presence of HIV-specific antibodies. Here we summarize the unique aspects of HIV MTCT including the immunopathogenesis of the different routes of transmission, and how transmission in the antenatal or postnatal periods may affect early life immune responses and HIV persistence. A more refined understanding of the complex interaction between viral, maternal, and fetal/infant factors may enhance the pursuit of strategies to achieve an HIV cure for pediatric populations.

Clinical, Virologic and Immunologic Correlates of Breast Milk Acquired Cytomegalovirus (CMV) Infections in Very Low Birth Weight (VLBW) Infants in a Newborn Intensive Care Unit (NICU) Setting.

Cytomegalovirus (CMV) infections acquired by very-low-birthweight (VLBW) infants are incompletely characterized. To examine CMV transmission in VLBW infants, we evaluated maternal DNAlactia, infant DNAemia, and presence of clinical disease in a blinded study in VLBW infants in our newborn intensive care unit (NICU). To examine these issues, 200 VLBW infants were enrolled in a surveillance study, with weekly breast milk and infant whole blood samples collected, as available. Virologic (breast milk and infant whole blood real time PCR) and immunologic (IgG, IgM, and IgG avidity) correlates were evaluated. A chart review examined whether infants had symptoms compatible with CMV disease. DNAlactia was identified in 65/150 (43%) of lactating mothers. Nine CMV infections were identified in 9/75 CMV-exposed infants (12% of exposed infants). A higher median breast milk viral load (DNAlactia) correlated with an increased likelihood of DNAemia (p = 0.05). Despite potential symptoms compatible with CMV infection, clinicians had not considered the diagnosis of CMV in 6/9 cases (66%). All of these infants had chronic lung disease at discharge. There was no correlation between IgG antibody titer or IgG avidity index and the likelihood of transmission or CMV disease. In conclusion, in VLBW infants receiving milk from seropositive mothers, CMV infections are commonly acquired, and are frequently unrecognized. Future studies are needed to determine whether routine surveillance for CMV of either breast milk or infant plasma is beneficial in preventing or recognizing infection.

COVID-19: Relationship and Impact on Breastfeeding-A Systematic Review.

COVID-19 is an infectious disease caused by the SARS-CoV-2 virus that was declared a Public Health Emergency of International Concern by the World Health Organization (WHO). One major problem faced is whether breastfeeding by mothers infected with the virus is safe. The objective of this work is to study the impact that the SARS-CoV-2 virus can have on breastfeeding, and whether the virus or antibodies can be transmitted from mother to child through milk. We carried out a systematic review of studies focusing on the impact of SARS-CoV-2 on breastfeeding by mothers infected with the virus. The bibliographic search was done through Medline (Pubmed), MedlinePlus and Google Scholar. From 292 records, the title and summary of each were examined according to the criteria, and whether they meet the selection criteria was also analysed. A total of 30 articles are included, of which 26 deal with the study of RNA virus in breastmilk and its involvement in breastfeeding and four on the study of SARS-CoV-2 antibodies in milk. Most studies have been conducted in China. Breastfeeding by mothers infected with SARS-CoV-2 is highly recommended for infants, if the health of the mother and the infant allow for it. Direct breastfeeding and maintaining appropriate protective measures should be encouraged. Should the mother's health condition not permit direct breastfeeding, infants should be fed with pumped breastmilk or donor milk.

Mother-to-Child Transmission of Arboviruses during Breastfeeding: From Epidemiology to Cellular Mechanisms.

Most viruses use several entry sites and modes of transmission to infect their host (parenteral, sexual, respiratory, oro-fecal, transplacental, transcutaneous, etc.). Some of them are known to be essentially transmitted via arthropod bites (mosquitoes, ticks, phlebotomes, sandflies, etc.), and are thus named arthropod-borne viruses, or arboviruses. During the last decades, several arboviruses have emerged or re-emerged in different countries in the form of notable outbreaks, resulting in a growing interest from scientific and medical communities as well as an increase in epidemiological studies. These studies have highlighted the existence of other modes of transmission. Among them, mother-to-child transmission (MTCT) during breastfeeding was highlighted for the vaccine strain of yellow fever virus (YFV) and Zika virus (ZIKV), and suggested for other arboviruses such as Chikungunya virus (CHIKV), dengue virus (DENV), and West Nile virus (WNV). In this review, we summarize all epidemiological and clinical clues that suggest the existence of breastfeeding as a neglected route for MTCT of arboviruses and we decipher some of the mechanisms that chronologically occur during MTCT via breastfeeding by focusing on ZIKV transmission process.

Breastfeeding and COVID-19.

The coronavirus disease 2019 (COVID-19) pandemic has affected all dimensions of health care, including exclusive breastfeeding assurance and its promotion. The risk of contagion and the consequences of the pandemic have raised concerns among future mothers or in those who are already breastfeeding due to the risk of possible transmission of the virus through breast milk, although active severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has not yet been detected in breast milk. The fear of contagion has favored mother-child isolation policies. So far, there is no evidence of vertical transmission, and the risk of horizontal transmission in the infant is similar to that of the general population. In infants with COVID-19, breastfeeding can even favorably change the clinical course of the disease.

La pandemia de enfermedad por coronavirus 2019 (COVID-19) ha afectado a todas las dimensiones de la atención en salud, entre ellas el aseguramiento de la lactancia materna exclusiva y su promoción. El riesgo de contagio y las consecuencias de la pandemia han provocado preocupación entre las futuras madres o las que se ya encuentran lactando debido al riesgo de una posible transmisión del virus a través de la leche materna. Aunque aún no se ha detectado el coronavirus 2 del síndrome respiratorio agudo grave (SARS-CoV-2) activo en la leche materna. El miedo al contagio ha favorecido las políticas de aislamiento madre-hijo. Hasta el momento no existe evidencia de transmisión vertical y el riesgo de transmisión horizontal en el lactante es similar al de la población general. En lactantes con COVID-19 la lactancia materna incluso puede cambiar favorablemente el curso clínico de la enfermedad.

Human Milk Virome Analysis: Changing Pattern Regarding Mode of Delivery, Birth Weight, and Lactational Stage.

The human milk (HM) microbiota is a significant source of microbes that colonize the infant gut early in life. The aim of this study was to compare transient and mature HM virome compositions, and also possible changes related to the mode of delivery, gestational age, and weight for gestational age. Overall, in the 81 samples analyzed in this study, reads matching bacteriophages accounted for 79.5% (mainly Podoviridae, Myoviridae, and Siphoviridae) of the reads, far more abundant than those classified as eukaryotic viruses (20.5%, mainly Herpesviridae). In the whole study group of transient human milk, the most abundant families were Podoviridae and Myoviridae. In mature human milk, Podoviridae decreased, and Siphoviridae became the most abundant family. Bacteriophages were predominant in transient HM samples (98.4% in the normal spontaneous vaginal delivery group, 92.1% in the premature group, 89.9% in the C-section group, and 68.3% in the large for gestational age group), except in the small for gestational age group (only ~45% bacteriophages in transient HM samples). Bacteriophages were also predominant in mature HM; however, they were lower in mature HM than in transient HM (71.7% in the normal spontaneous vaginal delivery group, 60.8% in the C-section group, 56% in the premature group, and 80.6% in the large for gestational age group). Bacteriophages still represented 45% of mature HM in the small for gestational age group. In the transient HM of the normal spontaneous vaginal delivery group, the most abundant family was Podoviridae; however, in mature HM, Podoviridae became less prominent than Siphoviridae. Myoviridae was predominant in both transient and mature HM in the premature group (all C-section), and Podoviridae was predominant in transient HM, while Siphoviridae and Herpesviridae were predominant in mature HM. In the small for gestational age group, the most abundant taxa in transient HM were the family Herpesviridae and a species of the genus Roseolovirus. Bacteriophages constituted the major component of the HM virome, and we showed changes regarding the lactation period, preterm birth, delivery mode, and birth weight. Early in life, the HM virome may influence the composition of an infant's gut microbiome, which could have short- and long-term health implications. Further longitudinal mother-newborn pair studies are required to understand the effects of these variations on the composition of the HM and the infant gut virome.

The Effect of Early Postnatal Nutrition on Human T Cell Leukemia Virus Type 1 Mother-to-Child Transmission: A Systematic Review and Meta-Analysis.

The main route of mother-to-child transmission (MTCT) of human T cell leukemia virus type 1 is vertical transmission via breastfeeding. Although the most reliable method for preventing MCTC is exclusive formula feeding (ExFF), short-term breastfeeding (STBF) or frozen-thawed breast milk feeding (FTBMF) has been offered as an alternative method if breastfeeding is strongly desired. The aim of this review was to clarify the pooled risk ratio of MCTC of STBF and FTBMF compared with ExFF. This study was registered with PROSPERO (number 42018087317). A literature search of PubMed, CINAHL, the Cochrane Database, EMBASE, and Japanese databases through September 2018 identified 1979 articles, 10 of which met the inclusion criteria. Finally, 11 articles, including these 10 studies and the report of a recent Japanese national cohort study, were included in the meta-analysis. The pooled relative risks of STBF ≤3 months, STBF ≤6 months, and FTBMF compared with ExFF were 0.72 (95% confidence interval (CI): 0.30-1.77; p = 0.48), 2.91 (95% CI: 1.69-5.03; p = 0.0001), and 1.14 (95% CI: 0.20-6.50; p = 0.88), respectively. This meta-analysis showed no statistical difference in the risk of MTCT between STBF ≤3 months and ExFF, but the risk of MTCT significantly increased in STBF ≤6 months.

Breast Milk and Breastfeeding of Infants Born to SARS-CoV-2 Positive Mothers: A Prospective Observational Cohort Study.

OBJECTIVE: There are limited published data on the transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus from mothers to newborns through breastfeeding or from breast milk. The World Health Organization released guidelines encouraging mothers with suspected or confirmed COVID-19 to breastfeed as the benefits of breastfeeding outweighs the possible risk of transmission. The objective of this study was to determine if SARS-CoV-2 was present in the breast milk of lactating mothers who had a positive SARS-CoV-2 nasopharyngeal swab test prior to delivery, and the clinical outcomes for their newborns. STUDY DESIGN: This was a single-center, observational, prospective cohort study. Maternal-newborn dyads that delivered at New York University Langone Hospital Brooklyn with confirmed maternal SARS-CoV-2 positive screen test at the time of admission were recruited for the study. Breast milk samples were collected during postpartum hospitalization and tested for the presence of SARS-CoV-2 genes N1 and N2 by two-step reverse transcription polymerase chain reaction. Additionally, the clinical characteristics of the maternal newborn dyad, results of nasopharyngeal SARS-CoV-2 testing, and neonatal follow-up data were collected. RESULTS: A total of 19 mothers were included in the study and their infants who were all fed breast milk. Breast milk samples from 18 mothers tested negative for SARS-CoV-2, and 1 was positive for SARS-CoV-2 RNA. The infant who ingested the breast milk that tested positive had a negative nasopharyngeal test for SARS-CoV-2, and had a benign clinical course. There was no evidence of significant clinical infection during the hospital stay or from outpatient neonatal follow-up data for all the infants included in this study. CONCLUSION: In a small cohort of SARS-CoV-2 positive lactating mothers giving birth at our institution, most of their breast milk samples (95%) contained no detectable virus, and there was no evidence of COVID-19 infection in their breast milk-fed neonates. KEY POINTS: · Breast milk may rarely contain detectable SARS-CoV-2 RNA and was not detected in asymptomatic mothers.. · Breast milk with detectable SARS-CoV-2 RNA from a symptomatic mother had no clinical significance for her infant.. · Breast feeding with appropriate infection control instructions appears to be safe in mother with COVID infection..