Positive association of breastfeeding on respiratory syncytial virus infection in hospitalized infants: a multicenter retrospective study

The Role of Breastfeeding in Acute Respiratory Infections in Infancy

BACKGROUND

Acute respiratory infections (ARIs) affect the respiratory tract, are often caused by viruses such as respiratory syncytial virus and rhinovirus, and present symptoms such as coughing, fever, respiratory distress and breathing difficulty. The global adherence to exclusive breastfeeding (BF) for the first 6 months of life has reached 44%, supported by World Health Organization and United Nations International Children's Emergency Fund efforts. BF provides vital nutrients and contributes to infant immune system development, protecting against infections. The role of BF in preventing and reducing complications of ARIs in infants is gaining attention, prompting a review of current data and future research needs. This review aims to summarize the evidence on the role of BF in reducing the risk and severity of ARIs in infants, elucidate the adaptations in breast milk composition during infections and identify relevant research needs.

METHODS AND RESULTS

Human milk (HM) is rich in immunoglobulins, antimicrobial peptides, and immunomodulatory factors that protect against various pathogens, including respiratory viruses. Several studies have demonstrated that BF is associated with a significant reduction in hospitalization, oxygen requirements, and mortality in infants with ARIs. The effectiveness of BF varies according to the specific respiratory virus, and a longer duration of exclusive BF appears to enhance its protective effect. It is documented that the composition of HM adjusts dynamically in response to infections, fortifying the infant's immune defenses. Specific immunological components of HM, including leukocytes and immunoglobulins, increase in response to infection in the infant, contributing to the enhancement of the immune defense in infants. Immune-boosting microRNAs enhance immune transfer to the infants and promote early gut maturation, and the HM microbiome along with other factors modifies the the infant's gut microbiome and immune system.

CONCLUSIONS

BF defends infants from respiratory infections, and the investigation of the microRNAs in HM offers new insights into its antiviral properties. The promotion of BF, especially in vulnerable communities, is of paramount importance in alleviating the global burden of ARIs in infancy.

Management of Acute Bronchiolitis in Spoke Hospitals in Northern Italy: Analysis and Outcome

Bronchiolitis is an acute viral infection of the lower respiratory tract that affects infants and young children. Respiratory syncytial virus (RSV) is the most common causative agent; however, other viruses can be involved in this disease. We retrospectively reviewed the clinical features of infants aged less than 12 months hospitalized for acute bronchiolitis in our Pediatric Units of Chivasso, Cirié, and Ivrea in Piedmont, Northern Italy, over two consecutive bronchiolitis seasons (September 2021-March 2022 and September 2022-March 2023). Patient-, disease-, and treatment-related variables were analyzed. The probability of therapeutic success (discharge home) was 96% for all patients (93% for RSV vs. 98% for non-RSV patients, p > 0.05). Among 192 patients, 42 infants (22%) underwent high-flow oxygen support (HFNC), and only 8 (4%) needed to be transferred to our hub referral hospital. Factors associated with hub hospital transfer were the age under 1 month and the failure of HFNC. The wide and increasing use of HFNC in pediatric inpatients improved the management of bronchiolitis in Spoke hospitals, reducing transfer to a hub hospital provided with Intensive Care Units.

The Current Status of Prolonged Breastfeeding and Its Related Factors in Korean Infants and Their Mothers: A Nationwide Cross-Sectional Study

BACKGROUND

International authorities recommend prolonged breastfeeding (PBF) for 12-24 months or more with 6 months of exclusive breastfeeding (EBF). Based on the Korean National Health and Nutrition Examination Survey (KNHANES) data, this study attempted to help encourage and educate breastfeeding (BF) over 1 year by investigating long-term BF trends and related factors in Korean infants and their mothers.

METHODS

This cross-sectional study was based on data on children aged 12-23 months and their mothers from 2010 to 2020. BF rates were compared between KNHANES V (2010-2012), KNHANES VI (2013-2015), KNHANES VII (2016-2018), and part of KNHANES VIII (2019-2020). In addition, data related to mothers and infants, including demographics, socioeconomic, educational, and health status, were collected, and their association with BF status was analyzed.

RESULTS

Of the 933 infants included in the study, the proportions achieving full BF at 6 months of age and PBF at 12 and 18 months were 34.8%, 33.7%, and 7.1%, respectively. Over the past 10 years, the trends of all three BF practices have significantly decreased since 2016 (P < 0.001). Of the 849 infants whose maternal data were available, multiple logistic regression analysis showed that EBF for 6 months (defined as full BF at 1, 3, and 6 months of age) positively correlated with maternal and infants' factors such as unemployed status, past BF experience, no history of drinking, and infants' birth weight of ≥ 2.5 kg. The mother's education level, particularly the nutrition label impact, current employment status, and smoking and drinking status, were significantly associated with PBF for ≥ 12 months but were not related to PBF for ≥ 18 months, except for drinking status.

CONCLUSIONS

In Korea, the long-term BF rate of ≥ 12 months has declined in the past 10 years, and BF becomes rare after 18 months. Higher maternal interest in nutrition information appears to be driving access to PBF over 12 months than EBF for 6 months or PBF over 18 months. To promote PBF over 12 months in Korea, it may be helpful to strengthen nutrition education that specifically emphasizes the benefits of PBF along with EBF, especially during infant health examinations.

Risk Factors for Severe Respiratory Syncytial Virus Infection in Hospitalized Children

BACKGROUND

RSV often leads to hospitalization, and accurate knowledge of risk factors is crucial.

METHODS

We retrospectively analyzed laboratory-confirmed RSV hospitalizations regarding pregnancy factors, birth status, cigarette smoke exposure, nutrition, social conditions, clinical presentation, and severe disease defined as a need for passive oxygen therapy (pO2Tx), the presence of pneumonia, respiratory failure, intensive care unit (ICU) transfer, and prolonged hospitalization.

RESULTS

A univariate analysis included 594 children (median age 4 months) and revealed a pO2Tx relationship with age ≤ 3 months (OR = 1.56), prematurity (OR = 1.71), being born during RSV season (OR = 1.72), smoke exposure during pregnancy (both parents (OR = 2.41, father (OR = 1.8)), dyspnea (OR = 5.09), and presence of apnea (OR = 5.81). Pneumonia was associated with maternal smoke exposure (OR = 5.01), fever (OR = 3.92), dyspnea (OR = 1.62), history of aspiration (OR = 4.63), and inversely with age ≤ 3 months (OR = 0.45). Respiratory failure was associated with prematurity (OR = 3.13) and apnea (OR = 18.78), while the lower odds were associated with older age (OR = 0.57 per month) and presence of fever (OR = 0.11). ICU transfer was associated with apnea (OR = 17.18), but an inverse association was observed with age (OR = 0.54) and fever (OR = 0.11). A prolonged hospital stay was associated with prematurity (OR = 1.76), low birth weight (OR = 2.89), aspiration (OR = 4.93), and presence of fever (OR = 1.51).

CONCLUSIONS

Age (up to 3 months), prematurity, and presence of apnea are risk factors for a severe RSV course.

Case-control study of exclusive breast feeding and severe bronchiolitis in the United States

BACKGROUND

Bronchiolitis is a major cause of infant illness, with few known modifiable risk factors. Breast feeding may reduce risk of severe bronchiolitis, but the association of exclusive vs. partial breast feeding with severe bronchiolitis is unclear.

OBJECTIVE

To estimate the association of exclusive vs. partial breast feeding during ages 0-2.9 months with bronchiolitis hospitalisation during infancy.

METHODS

We conducted a case-control study as a secondary analysis of two prospective US cohorts in the Multicenter Airway Research Collaboration. Cases were enrolled in a 17-centre study of infants hospitalised for bronchiolitis during 2011-2014 (n = 921). Controls were enrolled in a five-centre study of healthy infants during 2013-2014 and 2017 (n = 719). Breast feeding history during ages 0-2.9 months was collected by parent interview. Among breastfed infants, the association of exclusive vs. partial breast feeding with odds of bronchiolitis hospitalisation was estimated using a multivariable logistic regression model adjusted for demographic variables, parental asthma history, and early-life exposures. As a secondary analysis, we estimated the associations of exclusive, predominant, and occasional breast feeding vs. no breast feeding with the odds of bronchiolitis hospitalisation.

RESULTS

Among 1640 infants, the prevalence of exclusive breast feeding was 187/921 (20.3%) among cases and 275/719 (38.3%) among controls. Exclusive vs. partial breast feeding was associated with 48% reduced odds of bronchiolitis hospitalisation (adjusted odds ratio [OR] 0.52, 95% confidence interval [CI] 0.39, 0.69). In the secondary analysis, exclusive vs. no breast feeding was associated with 58% reduced odds of bronchiolitis hospitalisation (OR 0.42, 95% CI 0.23, 0.77), whereas predominant breast feeding (OR 0.77, 95% CI 0.37, 1.57) and occasional breast feeding (OR 0.98, 95% CI 0.57, 1.69) were not associated with meaningfully reduced odds of bronchiolitis hospitalisation.

CONCLUSION

Exclusive breast feeding had a strong protective association against bronchiolitis hospitalisation.

Altered intestinal microbiota in children with bronchiolitis

Objective

To investigate the correlation between the alteration of intestinal microbiota and disease in children with bronchiolitis.

Methods

Fifty seven children diagnosed with bronchiolitis from January 2020 to January 2022 in our pediatric department were included as the case group, and another 36 normal children were included as the control group. Stool and blood were collected from both groups for high-throughput sequencing, untargeted metabolite detection and ELISA. A mouse model of RSV infection was established to validate the results of clinical case detection.

Results

Body weight, passive smoking, and a host of other factors were possible as acute bronchiolitis influencing factors in the onset of acute bronchiolitis. The alpha diversity Shannon, Simpson and Pielou's evenness indices were significantly lower in children with acute bronchiolitis than in healthy children with gated levels of Firmicutes, Bacteroidetes and genus levels of Clostridium and other short chain fatty acid-producing bacteria. The relative abundance of short-chain fatty acid (SCFAs)-producing bacteria decreased and the abundance of genus-level sphingolipid-producing bacteria Sphingomonas increased; the progression of acute bronchiolitis is likely to be associated with the abundance of Clostridium and Sphingomonas and higher fecal amino acid concentrations, including FF-MAS, L-aspartic acid, thioinosinic acid, picolinic acid; supplementation with Clostridium butyricum significantly alleviated RSV infection-induced lung inflammation.

Conclusion

The progression of bronchiolitis may be associated with altered intestinal microbiota, decreased SCFAs and elevated sphingolipids metabolism in children. Some fecal bacteria and metabolites may predict the onset of bronchiolitis, and oral administration of Clostridium butyricum may alleviate RSV infection-induced pulmonary inflammation.

Maternal transfer of IgA and IgG SARS-CoV-2 specific antibodies transplacentally and via breast milk feeding

BACKGROUND

Although there have been many studies on antibody responses to SARS-CoV-2 in breast milk, very few have looked at the fate of these in the infant, and whether they are delivered to immunologically relevant sites in infants.

METHODS

Mother/infant pairs (mothers who breast milk fed and who were SARS-CoV-2 vaccinated before or after delivery) were recruited for this cross-sectional study. Mother blood, mother breast milk, infant blood, infant nasal specimen, and infant stool was tested for IgA and IgG antibodies against SARS-CoV-2 spike trimer.

RESULTS

Thirty-one mother/infant pairs were recruited. Breast milk fed infants acquired systemic anti-spike IgG antibodies only if their mothers were vaccinated antepartum (100% Antepartum; 0% Postpartum; P<0.0001). Breast milk fed infants acquired mucosal anti-spike IgG antibodies (in the nose) only if their mothers were vaccinated antepartum (89% Antepartum; 0% Postpartum; P<0.0001). None of the infants in either group had anti-spike IgA in the blood. Surprisingly, 33% of the infants whose mothers were vaccinated antepartum had high titer anti-spike IgA in the nose (33% Antepartum; 0% Postpartum; P = 0.03). Half-life of maternally transferred plasma IgG antibodies in the Antepartum infant cohort was ~70 days.

CONCLUSION

Vaccination antepartum followed by breast milk feeding appears to be the best way to provide systemic and local anti-SARS-CoV-2 antibodies for infants. The presence of high titer SARS-CoV-2-specific IgA in the nose of infants points to the potential importance of breast milk feeding early in life for maternal transfer of mucosal IgA antibodies. Expectant mothers should consider becoming vaccinated antepartum and consider breast milk feeding for optimal transfer of systemic and mucosal antibodies to their infants.

Impact of breastfeeding on the incidence and severity of respiratory syncytial virus (RSV)-associated acute lower respiratory infections in infants: a systematic review highlighting the global relevance of primary prevention

BACKGROUND

Respiratory syncytial virus (RSV) is the principal cause of acute lower respiratory infections (ALRI) among infants worldwide, and an important cause of morbidity, hospitalisation and mortality. While infants are universally exposed to RSV, most mortality occurs among normal term infants from low-income and middle-income countries. Breastfeeding has been suggested to have a protective effect against RSV infection. This study aims to determine the association of breastfeeding on the frequency and severity of RSV-associated ALRI among infants.

METHODS

A systematic review was conducted using keywords and Medical Subject Headings on MEDLINE, PubMed, Google Scholar, EMBASE, MedRxiv and Cochrane Central Register of Controlled Trials. Full-text articles published in English from 2000 to 2021 that studied exclusively or partially breastfed infants who developed RSV-associated ALRI <12 months of age were included. Covidence software-based evidence extraction and Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol guidelines were followed. Quality of evidence was analysed using UK National Service Framework grading and the risk-of-bias assessment using Robvis.

RESULTS

Among 1368 studies screened, 217 qualified full-text review and 198 were excluded based on pre-agreed criteria. Nineteen articles published from 12 countries that included 16 787 infants from 31 countries (of which 8 middle-income) were retained for analysis. Results indicate that non-breastfeeding practices pose a significant risk for severe RSV-associated ALRI and hospitalisation. Exclusive breastfeeding for >4-6 months significantly lowered hospitalisation, length of stay, supplemental oxygen demand and admission to intensive care units.

CONCLUSION

In the context of no effective or standardised treatment for established RSV-associated ALRI, available evidence suggest that breastfeeding is associated with lower frequency and severity of RSV-associated ALRI, based on observational studies of variable grades of evidence and risk-of-bias. With both exclusive and partial breastfeeding benefiting infants who develop RSV-associated ALRI, breastfeeding should be promoted globally as an adjunct primary prevention; in addition to emerging immunoprophylaxis and maternal immunisation strategies.

Maternal Immunization Using a Protein Subunit Vaccine Mediates Passive Immunity against Zaire ebolavirus in a Murine Model

The Ebola virus has caused outbreaks in Central and West Africa, with high rates of morbidity and mortality. Clinical trials of recombinant virally vectored vaccines did not explicitly include pregnant or nursing women, resulting in a gap in knowledge of vaccine-elicited maternal antibody and its potential transfer. The role of maternal antibody in Ebola virus disease and vaccination remains understudied. Here, we demonstrate that a protein subunit vaccine can elicit robust humoral responses in pregnant mice, which are transferred to pups in breastmilk. These findings indicate that an intramuscular protein subunit vaccine may elicit Ebola-specific IgG capable of being transferred across the placenta as well as into the breastmilk. We have previously shown protective efficacy with these vaccines in non-human primates, offering a potential safe and practical alternative to recombinant virally vectored vaccines for pregnant and nursing women in Ebola endemic regions.

Clinical importance of immunonutrition in infants: a review of the recent literature

During the last decades, the role of nutrition has been well elucidated in medicine, especially among critically ill infants and children. Many nutrients have the potential to modulate the immune system. A healthy immune system is essential for the prevention and recovery of many pediatric illnesses. Intervention using specific nutrients for the immune system is called immunonutrition. Immunonutrient supplementation has been attempted to modulate inflammatory or immune responses, leading to an improved clinical course of critically ill patients with prolonged nutritional supplementation parenterally or enterally. This review discusses immunomodulatory nutrients for infants based on the recent literature.

Early-Life Lung and Gut Microbiota Development and Respiratory Syncytial Virus Infection

Several environmental factors can influence the development and establishment of the early-life microbiota. For example, exposure to different environmental factors from birth to childhood will shape the lung and gut microbiota and the development of the immune system, which will impact respiratory tract infection and widespread disease occurrence during infancy and later in life. Respiratory syncytial virus (RSV) infects most infants by the age of two and is the primary cause of bronchiolitis in children worldwide. Approximately a third of infants hospitalized with bronchiolitis develop asthma later in life. However, it is unclear what factors increase susceptibility to severe RSV-bronchiolitis and the subsequent asthma development. In recent years, the role of the gut and lung microbiota in airway diseases has received increased interest, and more studies have focused on this field. Different epidemiological studies and experimental animal models have associated early-life gut microbiota dysbiosis with an increased risk of lung disease later in life. This work will review published evidence that correlated environmental factors that affect the early-life microbiota composition and their role in developing severe RSV infection.

Exclusive Breastfeeding and Vitamin D Supplementation: A Positive Synergistic Effect on Prevention of Childhood Infections?

Human milk is the best food for infants. Breastfeeding has been associated with a reduced risk of viral and bacterial infections. Breast milk contains the perfect amount of nutrients needed to promote infant growth, except for vitamin D. Vitamin D is crucial for calcium metabolism and bone health, and it also has extra-skeletal actions, involving innate and adaptive immunity. As exclusive breastfeeding is a risk factor for vitamin D deficiency, infants should be supplemented with vitamin D at least during the first year. The promotion of breastfeeding and vitamin D supplementation represents an important objective of public health.

BNT162b2 mRNA vaccine elicited antibody response in blood and milk of breastfeeding women

The importance of breastmilk in postnatal life lies in the strong association between breastfeeding and the reduction in the risk of infection and infection-related infant mortality. However, data regarding the induction and dynamics of breastmilk antibodies following administration of the Pfizer-BioNTech BNT162b2 COVID-19 mRNA vaccine is scarce, as pregnant and lactating women were not included in the initial vaccine clinical trials. Here, we investigate the dynamics of the vaccine-specific antibody response in breastmilk and serum in a prospective cohort of ten lactating women who received two doses of the mRNA vaccine. We show that the antibody response is rapid and highly synchronized between breastmilk and serum, reaching stabilization 14 days after the second dose. The response in breastmilk includes both IgG and IgA with neutralization capacity.

Breastmilk Feeding during the First 4 to 6 Months of Age and Childhood Disease Burden until 10 Years of Age

Background: Breastfeeding is recommended due to its beneficial effects on human health. However, the effect of breastfeeding on health differs, resulting in various childhood diseases. Objective: Our purpose was to investigate the association between breastfeeding at least in the first 4 months and the subsequent development of 15 certainly defined childhood diseases until 10 years of age, the all-cause hospitalization rate and growth at 6–7 years of age. Methods: Participants included propensity-score matched 188,052 children born between January 2008 and December 2009, who were followed up till 10 years of age. Data were taken from the National Investigation of birth Cohort in Korea study 2008 database. Risk ratios were obtained using a modified Poisson regression and weighted risk differences using binomial regression. Results: Compared to formula feeding, breastfeeding was associated with decreased risks of febrile convulsion, attention deficit hyperactivity disorder and autism spectrum disorder, pneumonia, acute bronchiolitis, hypertrophic pyloric stenosis, asthma, all-cause hospitalization, overweight/obesity and short stature. Exclusive breastfeeding at 4 to 6 months of age had similar results to exclusive breastfeeding over 6 months of age. Conclusions: Breastfeeding in early infancy reduces the risk for various childhood diseases, all-cause hospitalization rate, obesity, and short stature during childhood.

Anti-Infective, Anti-Inflammatory, and Immunomodulatory Properties of Breast Milk Factors for the Protection of Infants in the Pandemic From COVID-19

COVID-19 pandemic since the end of 2019 spreads worldwide, counting millions of victims. The viral invasion, systemic inflammation, and consequent organ failure are the gravest features of coronavirus disease 2019 (COVID-19), and they are associated with a high mortality rate. The aim of this study is to evaluate the role of breast milk in the COVID-19 pandemic, analyzing its antiviral, anti-inflammatory, and immunoregulatory effects due to its bioactive components, so numerous and important for the protection of infants. The study tried to demonstrate that all the components of human milk are capable of performing functions on all the pathogenic events recognized and described in COVID-19 disease. Those human milk factors are well-tolerated and practically free of side effects, so breast milk should become a research topic to discover therapies even in this epidemic. In the first part, the mechanisms of protection and defense of the breast milk elements will be delineated; in the second section, it will describe the human milk effects in viral infections and it will be hypothesized how the known mechanisms could act in COVID infection.

Appropriate care for neonates born to mothers with COVID-19 disease

The global COVID‐19 pandemic has been associated with high rates of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) transmission, morbidity and mortality in the general population. Evidence‐based guidance on caring for babies born to mothers with COVID‐19 is needed. There is currently insufficient evidence to suggest vertical transmission between mothers and their newborn infants. However, transmission can happen after birth from mothers or other carers. Based on the currently available data, prolonged skin‐to‐skin contact and early and exclusive breastfeeding remain the best strategies to reduce the risks of morbidity and mortality for both the mother with COVID‐19 and her baby.

Respiratory syncytial virus infection: why does disease severity vary among individuals?

Introduction: Respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory tract infections in infancy. While many infants are infected with RSV, the nature and severity of the disease vary among individuals. RSV causes bronchiolitis, pneumonia, and asthma exacerbation. However, most children infected with RSV have only mild upper airways disease and may be asymptomatic.Areas covered: Despite efforts to elucidate mechanisms for the various clinical responses to RSV infection, they remain largely unknown, suggesting that susceptibility and disease are influenced by multiple intrinsic and extrinsic factors. This article reviews the available literature on the field of RSV disease severity and discusses important factors associated to susceptibility and different disease outcome.Expert opinion: The severity of RSV-induced illness is a phenomenon that depends on a variety of graded mechanisms of interaction between the host, virus, and environment. This may lead to differences in the intensity of immune response in the lung and different courses of the disease. By characterizing, classifying, and grading the affecting factors in high-risk patients versus those who do not fall ill by RSV, we may find therapies or point to disease-limiting medications.