Early Identification of IgA Anti-SARSCoV-2 in Milk of Mother With COVID-19 Infection

Anti-SARS-CoV-2-specific antibodies in human breast milk following SARS-CoV-2 infection during pregnancy: a prospective cohort study

BACKGROUND

While the presence of SARS-CoV-2 in human breast milk is contentious, anti-SARS-CoV-2 antibodies have been consistently detected in human breast milk. However, it is uncertain when and how long the antibodies are present.

METHODS

This was a prospective cohort study including all consecutive pregnant women with confirmed SARS-CoV-2 infection during pregnancy, recruited at six maternity units in Spain and Hong Kong from March 2020 to March 2021. Colostrum (day of birth until day 4 postpartum) and mature milk (day 7 postpartum until 6 weeks postpartum) were prospectively collected, and paired maternal blood samples were also collected. Colostrum samples were tested with rRT-PCR-SARS-CoV-2, and skimmed acellular milk and maternal sera were tested against SARS-CoV-2 specific immunoglobulin M, A, and G reactive to receptor binding domain of SARS-CoV-2 spike protein 1 to determine the presence of immunoglobulins. Then, we examined how each immunoglobulin type in the colostrum was related to the time of infection by logistic regression analysis, the concordance between these immunoglobulins in the colostrum, maternal serum, and mature milk by Cohen's kappa statistic, and the relationship between immunoglobulin levels in mature milk and colostrum with McNemar.

RESULTS

One hundred eighty-seven pregnant women with confirmed SARS-CoV-2 infection during pregnancy or childbirth were recruited and donated the milk and blood samples. No SARS-CoV-2 was found in the human breast milk. Immunoglobulin A, G, and M were present in 129/162 (79·6%), 5/163 (3·1%), and 15/76 (19·7%) colostrum samples and in 17/62 (27·42%), 2/62 (3·23%) and 2/62 (3·23%) mature milk samples, respectively. Immunoglobulin A was the predominant immunoglobulin found in breast milk, and its levels were significantly higher in the colostrum than in the mature milk (p-value < 0.001). We did not find that the presence of immunoglobulins in the colostrum was associated with their presence in maternal, the severity of the disease, or the time when the infection had occurred.

CONCLUSIONS

Since anti-SARS-CoV-2 antibodies are found in the colostrum irrespective of the time of infection during pregnancy, but the virus itself is not detected in human breast milk, our study found no indications to withhold breastfeeding, taking contact precautions when there is active disease.

A case series exploring the human milk polyclonal IgA1 response to repeated SARS-CoV-2 vaccinations by LC-MS based fab profiling

Introduction

Upon vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) humans will start to produce antibodies targeting virus specific antigens that will end up in circulation. In lactating women such antibodies will also end up in breastmilk, primarily in the form of secretory immunoglobulin A1 (SIgA1), the most abundant immunoglobulin (Ig) in human milk. Here we set out to investigate the SIgA1 clonal repertoire response to repeated SARS-CoV-2 vaccination, using a LC-MS fragment antigen-binding (Fab) clonal profiling approach.

Methods

We analyzed the breastmilk of six donors from a larger cohort of 109 lactating mothers who received one of three commonly used SARS-CoV-2 vaccines. We quantitatively monitored the SIgA1 Fab clonal profile over 16 timepoints, from just prior to the first vaccination until 15  days after the second vaccination.

Results

In all donors, we detected a population of 89-191 vaccine induced clones. These populations were unique to each donor and heterogeneous with respect to individual clonal concentrations, total clonal titer, and population size. The vaccine induced clones were dominated by persistent clones (68%) which came up after the first vaccination and were retained or reoccurred after the second vaccination. However, we also observe transient SIgA1 clones (16%) which dissipated before the second vaccination, and vaccine induced clones which uniquely emerged only after the second vaccination (16%). These distinct populations were observed in all analyzed donors, regardless of the administered vaccine.

Discussion

Our findings suggest that while individual donors have highly unique human milk SIgA1 clonal profiles and a highly personalized SIgA1 response to SARS-CoV-2 vaccination, there are also commonalities in vaccine induced responses.

Breastfeeding vs. breast milk transmission during COVID-19 pandemic, which is more important?

The catastrophic coronavirus disease 2019 (COVID-19) pandemic has raised many health questions, and whether breast milk from SARS-CoV-2 infected mothers may be a vector for SARS-CoV-2 transmission has become a hot topic of concern worldwide. Currently, there are extremely limited and conflicting data on the risk of infection in infants through breastfeeding. For this reason, we investigated almost all current clinical studies and systematically analyzed the presence of SARS-CoV-2 and antibodies in the breast milk of mothers infected with SARS-CoV-2, their effects on newborns, and the mechanisms involved. A total of 82 studies were included in this review, of which 66 examined the presence of SARS-CoV-2 in breast milk samples from mothers diagnosed with COVID-19, 29 reported results of antibody detection of SARS-CoV-2 in breast milk, and 13 reported both nucleic acid and antibody test results. Seventeen studies indicated the presence of detectable SARS-CoV-2 nucleic acid in breast milk samples, and only two studies monitored viral activity, both of which reported that infectious viruses could not be cultured from RNA-positive breast milk samples. All 29 studies indicated the presence of at least one of the three antibodies, IgA, IgG and IgM, in breast milk. Five studies indicated the presence of at least one antibody in the serum of breastfed newborns. No COVID-19-related deaths were reported in all 1,346 newborns. Our study suggests that direct breastfeeding does not pose an additional risk of infection to newborns and that breast milk is a beneficial source of anti-SARS-CoV-2 antibodies that provide passive immune protection to infants. In addition, direct breastfeeding would provide maternal benefits. Our review supports the recommendation to encourage direct breastfeeding under appropriate infection control guidelines. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/#myprospero, identifier: 458043.

Physical activity in lactating women influences SARS-CoV-2-specific antibodies in human milk

Background

Moderate exercise results in a significant increase in serum and salivary immunoglobulins. Maternal physical activity might therefore also be a factor influencing antibody levels in human milk. This study aims to determine the influence of physical activity on SARS-CoV-2-specific Immunoglobulin A (IgA) in human milk and Immunoglobulin G (IgG) in serum.

Methods

In this prospective cross-sectional cohort study, all lactating women in the Netherlands were eligible to participate. SARS-CoV-2-specific IgA in human milk and IgG in serum were determined using an enzyme-linked immunosorbent assay (ELISA). Data on performed physical activity was collected using the Short Questionnaire to Assess Health enhancing physical activity (SQUASH), which includes intensity and duration of the performed activity.

Findings

In total, 356 out of 2312 lactating women tested positive for SARS-CoV-2-specific antibodies in serum. Of them, 323 filled in the questionnaire and were included in the analysis. An association between the activity score and SARS-CoV-2-specific antibodies in human milk (B = 1·035, 95·0% CI = 1·019 to 1·052, p = 0·042) and serum (B = 1·019, 95·0% CI = 1·009 to 1·029, p = 0·048) was demonstrated. No association was found between the duration of physical activity and SARS-CoV-2-specific antibodies in human milk or serum.

Interpretation

Our findings suggest that physical activity is beneficial for the levels of SARS-CoV-2-specific antibodies in human milk and serum, with the intensity of the physical activity being the most important contributor to this relationship. A higher level of antibodies in human milk might provide better immunological protection for infants against COVID-19.

Vertical transmission and maternal passive immunity post-SARS-CoV-2

Since 2020, the highly contagious nature and various transmission routes of SARS-CoV-2 have rendered the pandemic interminable. Vertical transmission (VT) through the placenta and breast milk, which is frequent for certain virus types, is thought to exist for SARS-CoV-2 and is hypothesized by many researchers. Conversely, antibodies are produced to counteract the effect of viruses. Since newborns' immunologic system cannot produce proper antibodies, maternal antibodies are usually transferred from mother to infant/fetus to meet the need. This theory leads to the hypothesis of transmission of antibodies through the placenta and breast milk following SARS-CoV-2 infection or vaccination. This paper further discusses these hypotheses, considering consequences of fetus/infant harm versus benefit.

The Secretory IgA Response in Human Milk Against the SARS-CoV-2 Spike Is Highly Durable and Neutralizing for At Least 1 Year of Lactation Postinfection

Background: Although in the early pandemic period COVID-19 pathology among young children and infants was typically less severe compared with that observed among adults, this has not remained entirely consistent as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants have emerged. There is an enormous body of evidence demonstrating the benefits of human milk antibodies (Abs) in protecting infants against a wide range of enteric and respiratory infections. It is highly plausible that the same holds true for protection against SARS-CoV-2 as this virus infects cells of the gastrointestinal and respiratory mucosae. Understanding the durability of a human milk Ab response over time after infection is critical. Objective: Previously, we examined the Abs present in milk of those recently infected with SARS-CoV-2 and concluded that the response was secretory immunoglobulin A (sIgA) dominant and that these titers were highly correlated with neutralization potency. The present study aimed to monitor the durability of the SARS-CoV-2 IgA and secretory Ab (sAb) response in milk from COVID-19-recovered lactating individuals over 12 months in the absence of vaccination or reinfection. Results: This analysis revealed a robust and durable spike-specific milk sIgA response, and at 9-12 months after infection, 88% of the samples exhibited titers above the positive cutoff for IgA and 94% were above the cutoff for sAb. Fifty percent of participants exhibited less than twofold reduction of spike-specific IgA through 12 months. A strong, significant positive correlation between IgA and sAb against spike persisted throughout the study period. Nucleocapsid-specific Abs were also assessed, which revealed significant background or cross-reactivity of milk IgA against this immunogen, as well as limited/inconsistent durability compared with Spike titers. Conclusion: These data suggest that lactating individuals are likely to continue producing spike-specific Abs in their milk for 1 year or more, which may provide critical passive immunity to infants against SARS-CoV-2 throughout the lactation period.

The secretory IgA (sIgA) response in human milk against the SARS-CoV-2 Spike is highly durable and neutralizing for at least 1 year of lactation post-infection

Although in the early pandemic period, COVID-19 pathology among young children and infants was typically less severe compared to that observed among adults, this has not remained entirely consistent as SARS-CoV-2 variants have emerged. There is an enormous body of evidence demonstrating the benefits of human milk antibodies (Abs) in protecting infants against a wide range of enteric and respiratory infections. It is highly plausible that the same holds true for protection against SARS-CoV-2, as this virus infects cells of the gastrointestinal and respiratory mucosae. Understanding the durability of a human milk Ab response over time after infection is critical. Previously, we examined the Abs present in milk of those recently infected with SARS-CoV-2, and concluded that the response was secretory IgA (sIgA)-dominant and that these titers were highly correlated with neutralization potency. The present study aimed to monitor the durability of the SARS-CoV-2 IgA and secretory Ab (sAb) response in milk from COVID-19-recovered lactating individuals over 12 months, in the absence of vaccination or re-infection. This analysis revealed a robust and durable Spike-specific milk sIgA response, that at 9-12 months after infection, 88% of the samples exhibited titers above the positive cutoff for IgA and 94% were above cutoff for sAb. Fifty percent of participants exhibited less than a 2-fold reduction of Spike-specific IgA through 12 months. A strong significant positive correlation between IgA and sAb against Spike persisted throughout the study period. Nucleocapsid-specific Abs were also assessed, which revealed significant background or cross reactivity of milk IgA against this immunogen, as well as limited/inconsistent durability compared to Spike titers. These data suggests that lactating individuals are likely to continue producing Spike-specific Abs in their milk for 1 year or more, which may provide critical passive immunity to infants against SARS-CoV-2 throughout the lactation period.

Detection of IgA and IgG Antibodies against the Structural Proteins of SARS-CoV-2 in Breast Milk and Serum Samples Derived from Breastfeeding Mothers

Background: COVID-19 vaccination or natural infection is associated with the development of immunity. The search of IgA and IgG antibodies against all the structural proteins (spike, nucleocapsid, membrane, and envelope) of SARS-CoV-2 in breastfeeding mothers is associated with immunity that can help the newborn avoid development of the infection. Methods: In this study, we analyzed 30 breastfeeding women that provided samples of breast milk and serum and evaluated the presence of IgA, total IgG, and subclasses against the structural proteins of SARS-CoV-2. Results: We reported a high seroprevalence to IgA (76.67-100%) and negativity to IgG against all analyzed proteins in breast milk. Seroprevalence in serum samples was around 10-36.67% to IgA and 23.3-60% to IgG. Finally, we detected the presence of the subclasses IgG1, IgG2, and IgG4 against all the structural proteins of SARS-CoV-2. Conclusions: This work provides evidence of the presence of IgA and IgG antibodies against the four structural proteins of SARS-CoV-2 in breast milk and serum samples derived from breastfeeding women, which can confer immunity to the newborn.

Impact of the Presence Anti-SARS-CoV-2 IgA in the Colostrum of Women Infected by COVID-19 During the Pregnancy in Neonatal Clinical Outcomes: A Cross-Sectional Study

OBJECTIVES

To describe the presence of anti-SARS-CoV-2 IgA and IgG in the blood and colostrum of women with COVID-19 infection during pregnancy and associate the presence of anti-SARS-CoV-2 IgA in colostrum with clinical symptoms of their newborns.

METHODS

A cross-sectional study was developed with 165 participants with COVID-19 infection during pregnancy and their newborns.

DATA COLLECTED

characteristics COVID-19 infection in pregnant women, gestational age, and clinical symptoms in their newborns (fever, hypothermia, respiratory distress, hypotonia, hypoactivity, hypoglycemia, cyanosis, vomiting/regurgitation, abdominal distention, and jaundice). Maternal blood and colostrum samples were collected postpartum to to detect the presence of IgA and IgG anti-SARS-CoV-2.

RESULTS

The median interval between COVID-19 diagnosis and delivery was 37.5 days (IQ = 12.0, 73.0 days). Clinical symptoms during hospitalization were observed in 55 newborns (33.3%), and two (1.6%) tested RT-PCR positive for COVID-19. Positive colostrum for anti-SARS-CoV-2 IgA was found in 117 (70.9%) women. The presence of anti-SARS-CoV-2 IgA in colostrum was associated independently with lower clinical symptoms in their newborns (OR = 0.42; 95% CI 0.202 to 0.84; p = 0.015).

CONCLUSIONS FOR PRACTICE

The presence of anti-SARS-CoV-2 IgA in colostrum was detected in more than two-thirds of the women evaluated and was associated with a lower frequency of clinical symptoms in their newborns.

A Live Attenuated COVID-19 Candidate Vaccine for Children: Protection against SARS-CoV-2 Challenge in Hamsters

Children are at risk of infection from severe acute respiratory syndrome coronavirus-2 virus (SARS-CoV-2) resulting in coronavirus disease (COVID-19) and its more severe forms. New-born infants are expected to receive short-term protection from passively transferred maternal antibodies from their mothers who are immunized with first-generation COVID-19 vaccines. Passively transferred antibodies are expected to wane within first 6 months of infant's life, leaving them vulnerable to COVID-19. Live attenuated vaccines, unlike inactivated or viral-protein-based vaccines, offer broader immune engagement. Given effectiveness of live attenuated vaccines in controlling infectious diseases such as mumps, measles and rubella, we undertook development of a live attenuated COVID-19 vaccine with an aim to vaccinate children beyond 6 months of age. An attenuated vaccine candidate (dCoV), engineered to express sub-optimal codons and deleted polybasic furin cleavage sites in the spike protein of the SARS-CoV-2 WA/1 strain, was developed and tested in hamsters. Hamsters immunized with dCoV via intranasal or intramuscular routes induced high levels of neutralizing antibodies and exhibited complete protection against the SARS-CoV-2 wild-type isolates, i.e., the Wuhan-like (USA-WA1/2020) and Delta variants (B.1.617.2) in a challenge study. In addition, the dCoV formulated with the marketed measles-rubella (MR) vaccine, designated as MR-dCoV, administered to hamsters via intramuscular route, also protected against both SARS-CoV-2 challenges, and dCoV did not interfere with the MR vaccine-mediated immune response. The safety and efficacy of the dCoV and the MR-dCoV against both variants of SARS-CoV-2 opens the possibility of early immunization in children without an additional injection.

The impact on colostrum oxidative stress, cytokines, and immune cells composition after SARS-CoV-2 infection during pregnancy

Background

Limited data are available regarding the differences between immunological, biochemical, and cellular contents of human colostrum following maternal infection during pregnancy with coronavirus 2 disease (COVID-19).

Objective

To investigate whether maternal COVID-19 infection may affect immunological, biochemical, and cellular contents of human colostrum.

Methods

Using a case-control study design, we collected colostrum from 14 lactating women with a previous diagnosis of COVID-19 during pregnancy and 12 without a clear diagnosis during September 2020 to May 2021. Colostrum samples were analysed for some enzymes and non-enzymatic oxidative stress markers (SOD, CAT, GPx, MDA, GSH, GSSG, H2O2, MPO) and for IL-1β, IL-6, tumour necrosis factor (TNF)-α, protein induced by interferon gamma (IP)-10, IL-8, IFN-λ1, IL12p70, IFN-α2, IFN-λ2/3, granulocyte macrophage colony stimulating factor (GM-CSF), IFN-β, IL-10 and IFN-γ, along with IgA and IgG for the SARS-CoV-2 S protein. We perform immunophenotyping to assess the frequency of different cell types in the colostrum.

Results

Colostrum from the COVID-19 symptomatic group in pregnancy contained reduced levels of H2O2, IFN-α2, and GM-CSF. This group had higher levels of GSH, and both NK cell subtypes CD3-CD56brightCD16-CD27+IFN-γ+ and CD3-CD56dimCD16+CD27- were also increased.

Conclusion

The present results reinforce the protective role of colostrum even in the case of mild SARS-Cov-2 infection, in addition to demonstrating how adaptive the composition of colostrum is after infections. It also supports the recommendation to encourage lactating women to continue breastfeeding after COVID-19 illness.

SARS-CoV-2-Specific IgG and IgA response in maternal blood and breastmilk of vaccinated naïve and convalescent lactating participants

Background

Recent studies have shown the presence of SARS-CoV-2-specific antibodies in the milk of breastfeeding mothers vaccinated with mRNA and convalescent. However, limited information is available in lactating women receiving other vaccine platforms used in developing countries, such as the inactivated SARS-CoV-2 vaccine BBIBP-CorV (Sinopharm) and the non-replicating adenovirus vaccines Sputnik V (Gamaleya Institute) and ChAdOx1-S (Oxford AstraZeneca).

Methods

Here, we evaluated anti-SARS-CoV-2 IgG and IgA levels in both serum and milk samples using a longitudinal and a cross-sectional cohort of 208 breastfeeding vaccinated women from Argentina with or without previous SARS-CoV-2 infection.

Results

The analysis showed that IgA levels remain constant in serum and milk of breastfeeding mothers between the first and second doses of vector-based vaccines (Sputnik V and ChAdOx1-S). After the second dose, anti-spike IgA was found positive in 100% of the serum samples and in 66% of breastmilk samples. In addition, no significant differences in milk IgA levels were observed in participants receiving BBIBP-CorV, Sputnik V or ChAdOx1-S. IgG levels in milk increased after the second dose of vector-based vaccines. Paired longitudinal samples taken at 45 and 120 days after the second dose showed a decrease in milk IgG levels over time. Study of IgA levels in serum and milk of vaccinated naïve of infection and vaccinated-convalescent breastfeeding participants showed significantly higher levels in vaccinated-convalescent than in participants without previous infection.

Conclusion

This study is relevant to understand the protection against SARS-CoV-2 by passive immunity in newborns and children who are not yet eligible to receive vaccination.

Nurse-Driven Interventions for Improving ELBW Neurodevelopmental Outcomes

Survival rates for extremely low-birth-weight (ELBW) infants are improving as neurodevelopmental impairment (NDI) rates stay stable, thereby increasing the overall number of infants with NDI. Although there are many determinants of NDI in this population, nutritional factors are of interest because they are readily modifiable in the clinical setting. Nurses can influence nutritional factors such as improving access to human milk feeding, using growth monitoring, establishing feeding policies, implementing oral care with colostrum, facilitating kangaroo care, and providing lactation education for the mother. All of these measures assist in leading to a decrease in NDI rates among ELBW infants.

Maternal mental health and breastfeeding amidst the Covid-19 pandemic: cross-sectional study in Catalonia (Spain)

Background

Covid-19 pandemic became an unexpected stressor for the entire population and, particularly, for pregnant women and lactating mothers. The alarming infectious risk together with the lockdown period could affect the emotional state of mothers-to-be, as well as breastfeeding rates, mother-baby bonding, or neonatal weight gain. The aim of this study is to describe the impact of this world health emergency in mother-baby pairs right after the first wave of Sars-Cov-2 pandemic (from March to May 2020).

Study design

A prospective observational study was carried out in mother–child dyads from those women who gave birth between June and August 2020 in a tertiary hospital. 91 mother-baby pairs were initially enrolled and 56 of them completed the follow-up. The study design had two separate steps: i) Step one: A clinical interview plus three psychometric tests (EPDS: Edinburgh Postnatal Depression Scale, PBQ: Postpartum Bonding Questionnaire and STAI-S: State-Trait Anxiety Inventory); ii) Step two: mother–child dyads were followed using a round of three brief telephone interviews (conducted at the newborn’s 7, 14 and 28 days of age) to accurately depict the newborn’s outcome in the neonatal period.

Results

In terms of maternal mental health, 25% of the sample screens positively in the EPDS, requiring further evaluation to rule out depressive symptoms. STAI-state and PBQ detect no abnormalities in either anxiety levels or mother–child bonding in our sample, as 100% of the mothers score below the cut-off points in each test (34 and 26 respectively). When comparing feeding practices (breast/bottle feeding) in 2020 to those practices during pre-pandemic years (2017–2019), a significant increase in breastfeeding was found in pandemic times. All newborns in the sample showed an adequate weight gain during their first month of life.

Conclusion

Women and newborns in our sample did not experience an increase in adverse outcomes in the neonatal period in terms of maternal mental health, breastfeeding rates, bonding and further neonatal development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-05036-9.

Durable antibody and effector memory T cell responses in breastmilk from women with SARS-CoV-2

Background

Given that only 25% of pregnant women elect to receive a COVID-19 vaccine, maternal SARS-CoV-2 infection remains an important route of conferring protective passive immunity to breastfed infants of mothers who are not vaccinated.

Methods

We enrolled 30 lactating participants between December 2020 and March 2021 who had a positive PCR-test and their first COVID-19 symptoms within the previous 21 days. Participants were asked to provide serial bilateral milk samples at 12 timepoints (~ every 3 days) over a period of 35 days. A second set of samples was collected at least four months after the beginning of the first set. Participants also were asked to provide their dried blood spots and infant stool samples. All samples were tested for receptor-binding domain (RBD)-specific immunoglobulin (Ig)A, IgG, and IgM. Milk samples were assessed for neutralizing ability against the spike protein and four SARS-CoV-2 variants: D614G, Alpha (B.1.1.7), Beta (B.1.351), and Gamma (P.1). Permeability of the breast epithelium was assessed by measuring the sodium to potassium ions (Na:K) in milk. Using flow cytometry, memory CD4 and CD8 T cells (CD45RO+ and CCR7+/-) and mucosal-homing CD4 and CD8 T cells (CD103+) were determined in cells from milk expressed at 35 days and at least 4 months after their first milk donation.

Results

Milk antibodies from SARS-CoV-2 positive participants neutralized the spike complex. Milk from 73, 90, and 53% of participants had binding reactivities to RBD-specific IgA, IgG, and IgM, respectively. In contrast to blood spots, which showed increased levels of IgG, but not IgA or IgM, the COVID-19 response in milk was associated with a robust IgA response. Twenty-seven percent of participants had increased breast-epithelium permeability, as indicated by Na:K ≥ 0.6. The percentage of CD45RO+CCR7- effector-memory T cells in the day ≥120 milk samples was significantly higher than day 35 samples (P< 0.05).

Conclusions

Antibodies in milk from participants with recent SARS-CoV-2 infection and those who recovered can neutralize the spike complex. For the first time we show that breastmilk T cells are enriched for mucosal memory T cells, further emphasizing the passive protection against SARS-CoV-2 conferred to infants via breastmilk.

Antibodies in the breastmilk of COVID-19 recovered women

Objective

Human milk contains antibodies against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) which may serve as a protective factor through passive immunization in infants. The objective of this study was to measure the levels of anti-SARS-CoV-2 IgG and IgA in human milk and serum after a SARS-CoV-2 infection.

Design

Breast milk and serum samples from 72 lactating mothers with confirmed SARS-CoV-2 asymptomatic or symptomatic infection were collected 1-229 days after the onset of clinical symptoms related to COVID-19. Seventeen mothers with no history of COVID-19 served as a control group. Enzyme-Linked ImmunoSorbent Assay was performed to analyze antibodies against SARS-CoV-2.

Results

SARS-CoV-2-IgA human milk antibodies were detected in mothers and their concentrations were consistently higher than SARS-CoV-2-IgG antibodies. The serum and breastmilk samples of women with COVID-19 was characterized by a higher concentration of anti-RBD IgA and IgG than the serum from the control group without COVID-19. No statistically significant difference was observed between the antibody levels in the serum samples obtained from symptomatic and asymptomatic women exposed to SARS-CoV-2 and between the antibody level and the time from a positive SARS-CoV-2 test result over the period studied.

Conclusion

Our results confirm the presence of SARS-CoV-2 IgA and IgG antibodies in the breastmilk of COVID-19 recovered women and the possibility of these antibodies in providing specific immunologic benefits to breastfeeding infants such as protection against the virus transmission and severity of the acquired COVID-19 disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04945-z.

Maternal vaccination as an additional approach to improve the protection of the nursling: Anti-infective properties of breast milk

Human milk constitutes a secretion with unique functions of both nourishing the nursling and providing protection against enteric and respiratory infections, mainly due to its content of secretory IgA antibodies but also due to the presence of a plethora of bioactive factors. Specific IgA antibodies are produced locally by plasma cells derived from B lymphocytes that migrate from other mucosae to the mammary gland during lactation, particularly from the gastrointestinal and respiratory tracts. Therefore, here, the authors will provide a comprehensive review of the content and functions of different nutritional and bioactive anti-infectious components from breast milk, such as oligosaccharides, lactoferrin, haptocorrin, α-lactalbumin, k-casein, lysozyme, lactoperoxidase, mucin, fatty acids, defensins, cytokines and chemokines, hormones and growth factors, complement proteins, leukocytes and nucleic acids, including microRNAs, among many others, and the induction of antibody responses in breast milk after maternal vaccination with several licensed vaccines, including the anti-SARS-CoV-2 vaccine preparations used worldwide. Currently, in the midst of the pandemic, maternal vaccination has re-emerged as a crucial source of passive immunity to the neonate through the placenta and breastfeeding, considering that maternal vaccination can induce specific antibodies if performed during pregnancy and after delivery. There have been some reports in the literature about milk IgA antibodies induced by bacterial antigens or inactivated virus vaccines, such as anti-diphtheria-tetanus-pertussis, anti-influenza viruses, anti-pneumococcal and meningococcal polysaccharide preparations. Regarding anti-SARS-CoV-2 vaccines, most studies demonstrate elevated levels of specific IgA and IgG antibodies in milk with virus-neutralizing ability after maternal vaccination, which represents an additional approach to improve the protection of the nursling during the entire breastfeeding period.

Breastfeeding during the COVID-19 pandemic: what do we know so far?

Objective

This study aimed to conduct a literature review on safety in breastfeeding in mothers with COVID-19. An integrative review of national and international literature was carried out.

Methods

The search took place in the SciELO, LILACS and MEDLINE^® databases.

Results

A total of 25 scientific articles that specifically addressed the theme of breastfeeding and its risk and protective factors for infection by SARS-CoV-2 were selected. According to the studies analyzed, although the presence of viral RNA had already been detected by reverse transcriptase polymerase chain reaction in breast milk samples, there are still no proven cases of vertical transmission via human milk.

Conclusion

Breastfeeding appears to be safe if practiced according to precaution measures recommended by the World Health Organization. In addition, there is evidence of a potential for immunological protection by transfer of antibodies against SARS-CoV-2 in breast milk. Breastfeeding should continue to be promoted even in cases of mothers with clinical suspicion or confirmation of COVID-19, as well as the provision of expressed breast milk in cases where there is no possibility of direct breastfeeding.

Development and Primary Application of an Indirect ELISA Based on Rep Protein to Analyze Antibodies against Porcine Cocirvirus-like Virus (PCLV)

Porcine circovirus-like virus (PCLV) is a member of circovirus that contains a single-strand DNA genome, which may be one of the pathogens that causes diarrheal symptoms in pigs. The Rep protein encoded by the genome of PCLV may be responsible for viral genome replication. The development of serological detection methods for PCLV is of great necessity for clinical diagnosis, as well as epidemiological investigations. Therefore, this study attempted to build an indirect enzyme-linked immunosorbent assay (ELISA) to examine antibodies against PCLV based on the His-tagged recombinant Rep protein. Full-length PCLV Rep protein was induced and expressed in E. coli and was purified as an antigen to establish an ELISA detection kit. The purified Rep protein was used to inject into mice to produce specific antibodies. There was no cross-reaction of Rep-based ELISA with antisera against other porcine viruses. The intra-assay and inter-assay coefficient variations (CVs) were 0.644–8.211% and 0.859–7.246%, respectively, indicating good repeatability. The non-cross-reaction with TGEV, PRRSV and PCV2 testing showed high sensitivity and high specificity for this ELISA assay. A total of 1593 serum samples collected from different pig farms in Jiangxi Province were tested for anti-PCLV Rep antibodies, and 284 (17.83%) of the 1593 samples were Rep antibody positive. Altogether, the indirect ELISA detection tool developed in this study could be applied to examine serum of PCLV antibodies with good repeatability, high sensitivity and high specificity. In addition, field sample detection results suggested that the PCLV antibody has a low prevalence in pig populations in Jiangxi Province of China.

Comparing the human milk antibody response after vaccination with four COVID-19 vaccines: A prospective, longitudinal cohort study in the Netherlands

BACKGROUND

Vaccination of lactating women against COVID-19 may protect not only themselves but also their breastfed infant through human milk. Therefore, it is important to gain insight into the human milk antibody response after immunization with the various vaccines that are currently widely used. The aim of this study is to determine and compare the antibody response in human milk following vaccination with mRNA- and vector-based vaccines up to over two months post-vaccination.

METHODS

This prospective cohort study was conducted in the Netherlands between January 06, 2021 and July 31, 2021. Participants were recruited through social media. Human milk samples were collected longitudinally during a period of 70 days from women receiving one of the four different severe acute respiratory coronavirus 2 (SARS-CoV-2) vaccines: Pfizer-BioNTech (BNT162b2), Moderna (mRNA-1273), Oxford/AstraZeneca (AZD1222) and Johnson&Johnson (Ad26.COV2.S). SARS-CoV-2-specific antibodies were measured using an enzyme-linked immunosorbent assay. The area under the curve (AUC) of the Immunoglobulins A (IgA) and G (IgG) antibody response was determined over 15 and 70 days following the first vaccination and compared between the different vaccines.

FINDINGS

This study enrolled 134 vaccinated lactating women of whom 97 participated the entire study period. In total, 1887 human milk samples were provided. The human milk antibody response differed between SARS-CoV-2 vaccines over the study period. The mean AUC of SARS-CoV-2-specific IgA, but not IgG, in human milk over 15 days was higher after vaccination with an mRNA-based vaccine than a vector-based vaccine (AUC with respect to ground [AUCg] ± the standard error of the mean [SEM] for IgA was 6·09 ± 0·89 in the BNT162b2 group, 7·48 ± 1·03 in the mRNA-1273 group, 4·17 ± 0·73 in the AZD1222 group, and 5·71 ± 0·70 in the Ad26.COV2.S group). Over a period of 70 days, the mean AUCg of both IgA and IgG was higher after vaccination with an mRNA-based vaccine than a vector-based vaccine (AUCg ± SEM for IgA was 38·77 ± 6·51 in the BNT162b2 group, 50·13 ± 7·41 in the mRNA-1273 group, 24·12 ± 5·47 in the AZD1222 group, and 28·15 ± 6·69 in the Ad26.COV2.S group; AUCg ± SEM for IgG was 40·43 ± 2·67 in the BNT162b2 group, 37·01 ± 2·38 in the mRNA-1273 group, 16·04 ± 5·09 in the AZD1222 group, and 10·44 ± 2·50 in the Ad26.COV2.S group).

INTERPRETATION

Overall, maternal vaccination during lactation with an mRNA-based vaccine resulted in higher SARS-CoV-2 antibody responses in human milk compared to vector-based vaccines. Therefore, vaccination with mRNA-based vaccines, preferably with the mRNA-1273 vaccine, might not only provide better immunological protection for the mother but also for her breastfed infant.

FUNDING

Stichting Steun Emma Kinderziekenhuis and the Amsterdam Infection and Immunity Institute (grant 24175).

Recommendations for breastfeeding during Coronavirus Disease 2019 (COVID-19) pandemic

Background

Coronavirus Disease 2019 (COVID-19) has spread worldwide. The safety of breastfeeding of SARS-CoV-2-positive women has not yet reached a consensus among the scientific community, healthcare providers, experts in lactation care, health organizations and governments. This study was conducted to summarize the latest evidence about the safety of breastfeeding among suspected/confirmed infected mothers and to summarize the recommendations on breastfeeding during COVID-19 from different organizations.

Methods

A comprehensive literature review of publications about the safety of breastfeeding among SARS-CoV-2-infected mothers was conducted. Scientific databases were searched up to 26 May 2021. The evidence was summarized into five perspectives according to a framework proposed by van de Perre et al. with certain modifications. Moreover, websites of different health organizations were visited to gather the recommendations for breastfeeding.

Results

The current evidence demonstrated that the majority of infants breastfed by infected mothers were negative for SARS-CoV-2. Breast milk samples from suspected/infected mothers mainly demonstrated negative results in SARS-CoV-2 viral tests. There was insufficient evidence proving the infectivity of breast milk from infected mothers. Recent studies found other transmission modalities (e.g., milk containers, skin) associated with breastfeeding. Specific antibodies in the breast milk of infected mothers were also found, implying protective effects for their breastfed children. According to van de Perre’s criteria, the breast milk of infected mothers was unlikely to transmit SARS-CoV-2. Owing to the low quality of the current evidence, studies with a more robust design are needed to strengthen the conclusion regarding the safety of breastfeeding. Further studies to follow up the health status of infants who were directly breastfed by their suspected/infected mothers, to collect breast milk samples at multiple time points for viral tests and to examine specific antibodies in breast milk samples are warranted. Current recommendations on breastfeeding during COVID-19 from different organizations are controversial, while direct breastfeeding with contact precautions is generally suggested as the first choice for infected mothers.

Conclusions

This review determined the safety of breastfeeding and identified the focus for further research during the COVID-19 pandemic. Recommendations on breastfeeding are suggested to be updated in a timely manner according to the latest evidence.

The IgA in milk induced by SARS-CoV-2 infection is comprised of mainly secretory antibody that is neutralizing and highly durable over time

Approximately 10% of infants infected with SARS-CoV-2 will experience COVID-19 illness requiring advanced care. A potential mechanism to protect this population is passive immunization via the milk of a previously infected person. We and others have reported on the presence of SARS-CoV-2-specific antibodies in human milk. We now report the prevalence of SARS-CoV-2 IgA in the milk of 74 COVID-19-recovered participants, and find that 89% of samples are positive for Spike-specific IgA. In a subset of these samples, 95% exhibited robust IgA activity as determined by endpoint binding titer, with 50% considered high-titer. These IgA-positive samples were also positive for Spike-specific secretory antibody. Levels of IgA antibodies and secretory antibodies were shown to be strongly positively correlated. The secretory IgA response was dominant among the milk samples tested compared to the IgG response, which was present in 75% of samples and found to be of high-titer in only 13% of cases. Our IgA durability analysis using 28 paired samples, obtained 4–6 weeks and 4–10 months after infection, found that all samples exhibited persistently significant Spike-specific IgA, with 43% of donors exhibiting increasing IgA titers over time. Finally, COVID-19 and pre-pandemic control milk samples were tested for the presence of neutralizing antibodies; 6 of 8 COVID-19 samples exhibited neutralization of Spike-pseudotyped VSV (IC₅₀ range, 2.39–89.4ug/mL) compared to 1 of 8 controls. IgA binding and neutralization capacities were found to be strongly positively correlated. These data are highly relevant to public health, not only in terms of the protective capacity of these antibodies for breastfed infants, but also for the potential use of such antibodies as a COVID-19 therapeutic, given that secretory IgA is highly in all mucosal compartments.

Titres and neutralising capacity of SARS-CoV-2-specific antibodies in human milk: a systematic review

OBJECTIVE

Synthesise evidence on production of SARS-CoV-2 antibodies in human milk of individuals who had COVID-19, and antibodies' ability to neutralise SARS-CoV-2 infectivity.

DESIGN

A systematic review of studies published from 1 December 2019 to 16 February 2021 without study design restrictions.

SETTING

Data were sourced from PubMed, MEDLINE, Embase, CNKI, CINAHL and WHO COVID-19 database. Search was also performed through reviewing references of selected articles, Google Scholar and preprint servers. Studies that tested human milk for antibodies to SARS-CoV-2 were included.

PATIENTS

Individuals with COVID-19 infection and human milk tested for anti-SARS-CoV-2 neutralising antibodies.

MAIN OUTCOME MEASURES

The presence of neutralising antibodies in milk samples provided by individuals with COVID-19 infection.

RESULTS

Individual participant data from 161 persons (14 studies) were extracted and re-pooled. Milk from 133 (82.6%) individuals demonstrated the presence of anti-SARS-CoV-2 immunoglobulin A (IgA), IgM and/or IgG. Illness severity data were available in 146 individuals; 5 (3.4%) had severe disease, 128 (87.7%) had mild disease, while 13 (8.9%) were asymptomatic. Presence of neutralising antibodies in milk from 20 (41.7%) of 48 individuals neutralised SARS-CoV-2 infectivity in vitro. Neutralising capacity of antibodies was lost after Holder pasteurisation but preserved after high-pressure pasteurisation.

CONCLUSION

Human milk of lactating individuals after COVID-19 infection contains anti-SARS-CoV-2-specific IgG, IgM and/or IgA, even after mild or asymptomatic infection. Current evidence demonstrates that these antibodies can neutralise SARS-CoV-2 virus in vitro. Holder pasteurisation deactivates SARS-CoV-2-specific IgA, while high-pressure pasteurisation preserves the SARS-CoV-2-specific IgA function.

Safety of breast/chest-feeding by those infected by SARS-CoV-2

PURPOSE OF REVIEW

One important question from the outset of the pandemic has been whether a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected person's milk might be a vehicle for SARS-CoV-2 transmission. This review summarizes the most recent data on this topic.

RECENT FINDINGS

A SARS-CoV-2 sIgA response in milk after infection is very common. To date, there has been no evidence that SARS-CoV-2 transmits via human milk. Though viral RNA has been identified in a minority of milk samples studied, infectious virus particles have not.

SUMMARY

The highly dominant transmission route for SARS-CoV-2 is via inhalation of respiratory droplets containing virus particles. Other routes of transmission are possible, including fecal-oral, trans-placental, and to a much lesser extent, via a contaminated surface. SARS-CoV-2 cannot transmit via human milk. There is no evidence that infants should be separated from SARS-CoV-2-infected mothers who are well enough to establish or continue breastfeeding.

Neutralizing Antibodies and Cytokines in Breast Milk After Coronavirus Disease 2019 (COVID-19) mRNA Vaccination

Humoral and cellular immune responses to mRNA-based coronavirus disease 2019 (COVID-19) vaccination are present in the breast milk of most women and confer passive immunity to the nursing infant.

OBJECTIVE:

To evaluate immune responses to coronavirus disease 2019 (COVID-19) mRNA-based vaccines present in breast milk and transfer of the immune responses to breastfeeding infants.

METHODS:

We enrolled 30 lactating women who received mRNA-based COVID-19 vaccines from January through April 2021 in this cohort study. Women provided serial milk samples, including milk expressed before vaccination, across 2–3 weeks after the first dose, and across 3 weeks after the second dose. Women provided their blood, spotted on cards (dried blood spots), 19 days after the first dose and 21 days after the second dose. Stool samples from the breastfed infants were collected 21 days after mothers' second vaccination. Prepandemic samples of milk, dried blood spots, and infant stool were used as controls. Milk, dried blood spots, and infant stool were tested by enzyme-linked immunosorbent assay for receptor-binding domain (RBD)–specific immunoglobulin (Ig)A and IgG. Milk samples were tested for the presence of neutralizing antibodies against the spike and four variants of concern: D614G, Alpha (B.1.1.7), Beta (B.1.351), and Gamma (P.1). Levels of 10 cytokines were measured in milk samples.

RESULTS:

Milk from COVID-19-immunized women neutralized the spike and four variants of concern, primarily driven by anti-RBD IgG. The immune response in milk also included significant elevation of interferon-γ. The immune response to maternal vaccination was reflected in breastfed infants: anti-RBD IgG and anti-RBD IgA were detected in 33% and 30% of infant stool samples, respectively. Levels of anti-RBD antibodies in infant stool correlated with maternal vaccine side effects. Median antibody levels against RBD were below the positive cutoffs in prepandemic milk and infant stool samples.

CONCLUSION:

Humoral and cellular immune responses to mRNA-based COVID-19 vaccination are present in most women’s breast milk. The milk anti-RBD antibodies can neutralize severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike and variants of concern. Anti-RBD antibodies are transferred to breastfed infants, with the potential to confer passive immunity against SARS-CoV-2.

Risk transmission through breastfeeding and antibody in COVID-19 mother

OBJECTIVE

SARS-CoV-2 has spread beyond the world and makes a new challenge in the breastfeeding issue. There is some disagreement among breastfeeding management in confirmed COVID-19 patients China consensus but no evidence shows the transmission via breastfeeding. This paper aims to know the risk of transmission through breastfeeding in COVID-19 patients and antibodies in breast milk.

METHOD

We conducted a literature review of publicly available information to summarize knowledge about risk transmission through breastfeeding and antibody in mother confirmed COVID-19.

RESULT

A maternal woman was positive for COVID-19 in throat swabs show negative SARS-CoV-2 in breast milk. No evidence suggests the transmission of SARS-CoV-2 from mother to baby via vertical route or breast milk. IgG and IgA were detected in breast milk and potentially against SARS-CoV-2.

CONCLUSION

Mother with COVID-19 can continuing direct breastfeeding with appropriate hygiene precautions (using a mask and wash hand) and should remain separate (home isolation precautions) from other family members including the infant, except for breastfeeding.

Comparison of SARS-CoV-2-Specific Antibodies in Human Milk after mRNA-Based COVID-19 Vaccination and Infection

SARS-CoV-2-specific antibodies are secreted into human milk of infected or vaccinated lactating women and might provide protection to the breastfed infant against COVID-19. Differences in antibody response after these types of exposure are unknown. In this longitudinal cohort study, we compared the antibody response in human milk following SARS-CoV-2 vaccination or infection. We analyzed 448 human milk samples of 28 lactating women vaccinated with the SARS-CoV-2 vaccine BNT162b2 as well as 82 human milk samples of 18 lactating women with a prior SARS-CoV-2 infection. The levels of SARS-CoV-2-specific IgA in human milk were determined over a period of 70 days both after vaccination and infection. The amount of SARS-CoV-2-specific IgA in human milk was similar after SARS-CoV-2 vaccination and infection. After infection, the variability in IgA levels was higher than after vaccination. Two participants with detectable IgA prior to vaccination were analyzed separately and showed higher IgA levels following vaccination compared to both groups. In conclusion, breastfed infants of mothers who have been vaccinated with the BNT162b2 vaccine receive human milk with similar amounts of SARS-CoV-2-specific antibodies compared to infants of previously infected mothers.

Health care providers' awareness of breastfeeding practice recommendations during COVID-19 pandemic and associated factors in Northwest Ethiopia, 2021: A multicenter study

BACKGROUND

Prevention of coronavirus disease 2019 (COVID-19) transmission to newborns is one of the basic components of perinatal care in the era of the COVID-19 pandemic. As such, scientific evidence is compulsory for evidence-based practices. However, there was a scarcity of evidence on health care providers' awareness of breastfeeding practice recommendations during the COVID-19 pandemic in Ethiopia, particularly in the study setting.

OBJECTIVE

The study aimed at assessing healthcare providers' awareness of breastfeeding practice recommendations during the COVID-19 pandemic and associated factors among healthcare providers in northwest Ethiopia, 2021.

METHODS

A multicenter cross-sectional study was conducted among 405 healthcare providers working in hospitals of Gondar province from November 15, 2020, to March 10, 2021. A simple random sampling technique was employed to select the study subjects. Data were collected via a structured-self-administered questionnaire. EPI INFO version 7.1.2 and SPSS version 25 were used for data entry and analysis respectively. Binary logistic regression analyses were done to identify associated factors and the adjusted odds ratio (AOR) with its 95% confidence interval (CI) at a p-value of <0.05 was used to declare significant association.

RESULTS

The healthcare providers' awareness of breastfeeding practice recommendations during the COVID-19 pandemic was 40.7% (95% CI: 35.9, 45.6). Working in a tertiary hospital (AOR = 3.69; 95% CI: 2.24, 6.08), using COVID-19 guideline updates (AOR = 3.34; 95% CI: 2.1, 5.3), being trained on COVID-19 (AOR = 2.78; 95% CI: 1.74, 4.47), owning a smartphone and/or a computer (AOR = 2.26; 95% CI: 1.39, 3.68), and perceiving that COVID-19 is dangerous (AOR = 1.78; 95% CI: 1.05, 3.01) were factors positively associated with healthcare providers' awareness of breastfeeding practice recommendations during the pandemic of COVID-19.

CONCLUSION

Only two in five healthcare providers were aware of recommendations on breastfeeding practice during the COVID-19 pandemic and related to information of accessibility information on COVID-19. Therefore, expanding COVID-19 related information through the provision of COVID-19 training and guidelines to all levels of hospitals would improve health care providers' awareness of breastfeeding practice recommendations amid the COVID-19 pandemic.

Humoral and Cell-Mediated Immune Response in Colostrum from Women Diagnosed Positive for SARS-CoV-2

Objective: To evaluate the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in colostrum from women who tested positive for the virus. Methods: Between March and September 2020 we obtained bilateral colostrum samples collected on spot cards within 48 hours of delivery from 15 new mothers who had previously tested positive for SARS-CoV-2. Four of 15 women provided liquid colostrum, which was used for validating results obtained from spot cards. Archived bilateral colostrum samples collected from 8 women during 2011-2013 were used as pre-coronavirus disease 2019 (COVID-19) controls. All samples were tested for reactivity to the receptor binding domain (RBD) of the SARS-CoV-2 spike protein using an enzyme-linked immunosorbent assay that measures SARS-CoV-2 RBD-specific IgA, IgG, and IgM and for levels of 10 inflammatory cytokines (interferon-gamma [IFN-γ], tumor necrosis factor-alpha, interleukin [IL]-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13) using a multiplex electrochemiluminescent sandwich assay. Results: Our validation studies indicate that the levels of SARS-CoV-2-specific antibodies and the associated cytokines measured in liquid colostrum are comparable to levels eluted from spot cards. Bilateral colostrum samples from 73%, 73%, and 33% of the 15 COVID-19 mothers exhibited IgA, IgG, and IgM reactivity to RBD, respectively. In addition, symptomatic COVID-19 mothers had statistically significant elevated levels of 4 of the 10 inflammatory markers (IFN-γ, IL-4, IL-6, and IL-12) compared to asymptomatic COVID-19 mothers. Conclusions: A strong humoral immune response is present in the colostrum of women who were infected with SARS-CoV-2 before delivering. The evolution and duration of the antibody response, as well as dynamics of the cytokine response, remain to be determined. Our results also indicate that future large-scale studies can be conducted with milk easily collected on paper spot cards.

Clinical Characteristics of Newborn Infants Delivered to Pregnant Women With Laboratory-Confirmed COVID-19: A Single-Center Experience From Saudi Arabia

Introduction

In Saudi Arabia and countries around the world, clinical health practice has been transformed by the coronavirus 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). During the early days of the pandemic, it was a major challenge to care for pregnant women with laboratory-confirmed COVID-19 and their newborn infants. In this article, we share our experience in the management of newborn infants delivered to mothers with laboratory-confirmed COVID-19.

Methods

A prospective single-center observational study was conducted at King Abdulaziz Medical City in Jeddah, National Guard Health Affairs, Saudi Arabia. Data collection started in March 2020 and was completed in October 2020. The inclusion criteria included mothers with laboratory-confirmed COVID-19 and their newborn infants.

Results

A total of 45 pregnant women with polymerase chain reaction (PCR)-confirmed COVID-19 were included in the study. Their mean age was 30.23±5.92 years. The mode of delivery was spontaneous vaginal delivery in 27 women (60%), cesarean section in 15 women (33.3%), and assisted vaginal delivery in three women (6.7%). Three mothers (6.7%) required intensive care unit admission. A total of 45 babies were born and 25 were females (55.6%), 20 males (44.4%). None of the babies had specific symptoms related to COVID-19. All babies were tested negative on the two COVID-19 nasopharyngeal swabs. Babies were initially admitted to the NICU and one baby required prolonged NICU stay due to extreme prematurity (23 weeks), one baby died due to hypoxic-ischemic encephalopathy and respiratory distress syndrome, and the remaining babies were discharged home in a stable condition.

Conclusion

Our experience suggests that maternal outcomes are generally favorable and no difference between vaginal and cesarean delivery in the risk of virus transmission. With strict implementation of infection prevention measures, mother-to-infant transmission is very unlikely. Early bathing of the newborn infant is preferred to reduce the risk of transmission of infection to newborn infants and the hospital staff. Breastfeeding is safe if performed under strict infection prevention measures.

COVID-19 and breastfeeding: can SARS-CoV-2 be spread through lactation?

SARS-CoV-2 is a new betacoronavirus that was first reported in the Hubei province, China, in December 2019. The virus is likely transmitted through air droplets. However, there are reported cases where SARS-CoV-2-RNA was found in other samples, such as blood or stool. Nonetheless, there is limited information concerning the presence of viral RNA in pregnancy-related samples, specifically breast milk. However unlikely, there is still uncertainty regarding the possibility of vertical transmission from mother to infant through breastfeeding. This review aims to synthetize the literature written so far on this topic. Despite not being extensively researched, vertical transmission through breast milk seems unlikely. Case series showed that milk samples from mothers with COVID-19 were almost entirely negative. So far, there have been only 9 recorded cases of viral shedding in milk samples, uncertain however of the viability of the particles. Furthermore, WHO and UNICEF strongly encourage commencing breastfeeding after parturition, underlining the benefits of lactation. Moreover, some studies have proven the existence of IgG and IgA anti-SARS-CoV-2-antibodies in the maternal milk that could possibly play an important part in the neonate’s protection against the virus. Vertical transmission through lactation seems unlikely, most studies pointing towards the safety of breastfeeding. However, further larger-scale studies need to be performed in order to clarify a yet uncertain matter.

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.

Dynamics of breast milk antibody titer in the six months following SARS-CoV-2 infection

Background

: While a growing body of literature describes antibody dynamics in serum, little is known about breast milk antibody titers in the months following SARS-CoV-2 infection.

Objectives

: We evaluated the dynamics of the humoral immune response to SARS-CoV-2 in two women who were breastfeeding when infected. We assessed paired breast milk and serum samples for six months post-infection for antibodies specific to the SARS-CoV-2 receptor binding domain (RBD) of the spike protein.

Results

: Starting at 10 days after symptom onset, IgA antibody levels were persistent over a 6-month time period in human milk. For both mothers, no detectable IgA was found in the samples collected pre-symptom onset. RBD-specific IgG and IgM antibodies in tandem serum collected from the two donors demonstrated stable IgG levels over the six-month time period post-symptom onset.

Conclusions

: We found that breastfeeding mothers produced a durable IgA response for up to six months following COVID-19 infection, suggesting an important role for breast milk in protection of infants.

A reasoned approach towards administering COVID-19 vaccines to pregnant women

There are over 50 SARS-CoV-2 candidate vaccines undergoing Phase II and III clinical trials. Several vaccines have been approved by regulatory authorities and rolled out for use in different countries. Due to concerns of potential teratogenicity or adverse effect on maternal physiology, pregnancy has been a specific exclusion criterion for most vaccine trials with only two trials not excluding pregnant women. Thus, other than limited animal studies, gradually emerging development and reproductive toxicity data, and observational data from vaccine registries, there is a paucity of reliable information to guide recommendations for the safe vaccination of pregnant women. Pregnancy is a risk factor for severe COVID-19, especially in women with comorbidities, resulting in increased rates of preterm birth and maternal morbidity. We discuss the major SARS-CoV-2 vaccines, their mechanisms of action, efficacy, safety profile and possible benefits to the maternal-fetal dyad to create a rational approach towards maternal vaccination while anticipating and mitigating vaccine-related complications. Pregnant women with high exposure risks or co-morbidities predisposing to severe COVID-19 infection should be prioritised for vaccination. Those with risk factors for adverse effects should be counselled accordingly. It is essential to support patient autonomy by shared decision-making involving a risk-benefit discussion with the pregnant woman.

Coronavirus disease and vaccination during pregnancy and childbirth: a review of the Israeli perspective and experience

Purpose of the study: To discuss selected aspects of our local and national experience in treating and vaccinating pregnant women with SARS-CoV-2 infection and COVID-19 disease.Materials and methods: A comprehensive, retrospective review of COVID-19 parturients in our center as well as a detailed literature review of several aspects from the groundbreaking research done in Israel to investigate the direct obstetrical impact of COVID-19, indirect effect of the lockdown measures and the vaccination effort among pregnant women.Results: The study shows our local and national experience in treating COVID-19 in pregnancy and the maternal and neonatal impact of vaccination in nationwide scale. We treated our first COVID-19 pregnant patient on April 4th, 2020 reaching a total of 193 pregnant women, with PCR-positive SARS-CoV-2 by 8th March 2021. Several studies from Israel have evaluated pregnancy-related outcomes of COVID-19, be it maternal, obstetrical or neonatal complications. We suggest that only in a small subset of severely ill mothers, intubated and otherwise respiratory or hemodynamically unstable, an emergency cesarean delivery should be considered, factoring gestational age, in order to assist maternal ventilation and circulation, as well as to avoid possible secondary fetal compromise due the maternal deterioration.In addition, there is conflicting evidence as to the price of lockdown on obstetrical outcomes, i.e., not the direct medical impact of the virus, but rather the impact of the measures to contain its spread - mainly lockdowns, which has been a major tool in Israel to combat COVID-19.Finally, we demonstrate to overall safety and efficacy of vaccination pregnant women and the beneficial impact on pregnancy outcome and neonatal gain of protecting antibodies.Conclusion: The data emerging from Israel is overall reassuring, as for the association of COVID-19 with adverse pregnancy outcome and the possible protective effect of the vaccinations. Further, long term studies, should be conducted to answer the long-term maternal outcomes, as well and neonatal prognosis.

Consequences of Early Separation of Maternal-Newborn Dyad in Neonates Born to SARS-CoV-2 Positive Mothers: An Observational Study

As the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection continues its spread all over the world, data on perinatal management of the maternal-infant dyad are urgent. We performed an observational study to describe the effects of the early separation of the maternal-infant dyad, in case of maternal SARS-CoV-2 infection. We reported the medical records for 37 neonates born to 37 SARS-CoV-2 positive mothers in a setting of separation of the dyad after birth. Data on neonatal infection, clinical condition, and breastfeeding rate were recorded until the first month of life. No maternal deaths were recorded; 37.8% of women had at least one pregnancy-related complication. We reported a high adherence to recommended safety measures after discharged with 84.8% of the mothers using at least one personal protective device and 51.5% using all the protective devices. We reported one case of vertical transmission and no cases of horizontal transmission. However, the separation of the dyad had a negative impact on breastfeeding because only 23.5% of the newborns received exclusively human milk during the first month of life. Despite early separation of the dyad protecting the newborns from possible horizontal transmission of SARS-CoV-2, it negatively affects breastfeeding during the first months of life.

Breast Milk and COVID-19: From Conventional Data to "Omics" Technologies to Investigate Changes Occurring in SARS-CoV-2 Positive Mothers

In this context of COVID-19 pandemic, great interest has been aroused by the potential maternal transmission of SARS-CoV-2 by transplacental route, during delivery, and, subsequently, through breastfeeding. Some open questions still remain, especially regarding the possibility of finding viable SARS-CoV-2 in breast milk (BM), although this is not considered a worrying route of transmission. However, in BM, it was pointed out the presence of antibodies against SARS-CoV-2 and other bioactive components that could protect the infant from infection. The aim of our narrative review is to report and discuss the available literature on the detection of anti-SARS-CoV-2 antibodies in BM of COVID-19 positive mothers, and we discussed the unique existing study investigating BM of SARS-CoV-2 positive mothers through metabolomics, and the evidence regarding microbiomics BM variation in COVID-19. Moreover, we tried to correlate metabolomics and microbiomics findings in BM of positive mothers with potential effects on breastfed infants metabolism and health. To our knowledge, this is the first review summarizing the current knowledge on SARS-CoV-2 effects on BM, resuming both "conventional data" (antibodies) and "omics technologies" (metabolomics and microbiomics).

Early human milk lactoferrin during SARS-CoV-2 infection

BACKGROUND/AIM

Early human milk provides protection against viral infections due to its high nutritional value, abundance of maternal antibodies and the specific role of lactoferrin (Lf). Lf blocks the early interaction between SARS-CoV-2 and host cells by binding to specific cell receptors and has been proposed as a preventative and adjunct treatment for COVID-19. This preliminary report aimed to investigate concentrations of Lf in early milk of SARS-CoV-2 positive mothers versus non-infected controls.

MATERIAL AND METHODS

In a cohort of 13 SARS-CoV-2 positive mothers and 15 controls, breast milk concentrations of Lf were determined by ELISA on day 3 postpartum. Additionally, colostrum samples of infected mothers were analyzed for SARS-CoV-2 RNA detection and anti-SARS-CoV-2 IgA and IgG determination using RT-qPCR and ELISA, respectively.

RESULTS

No differences were found in breast milk Lf concentrations between SARS-CoV-2 positive mothers and controls. In a subgroup analysis, however, symptomatic mothers (n = 7) presented with lower breast milk Lf concentrations, as compared to asymptomatic mothers (p = .041) and healthy controls (p = .029). All milk samples tested negative for SARS-CoV-2 RNA. Early human milk of infected mothers displayed IgA and IgG SARS-CoV-2 specific reactivity.

CONCLUSIONS

Our data showed a different early breast milk Lf "profile" between COVID-19 symptomatic and asymptomatic mothers with the latter being at non-COVID levels (control group). SARS-CoV-2 RNA was not detected in any breast milk sample. Early human milk Lf levels are potentially influenced by the severity of maternal COVID-19 infection during pregnancy.

Review of Current COVID-19 Diagnostics and Opportunities for Further Development

Diagnostic testing plays a critical role in addressing the coronavirus disease 2019 (COVID-19) pandemic, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Rapid and accurate diagnostic tests are imperative for identifying and managing infected individuals, contact tracing, epidemiologic characterization, and public health decision making. Laboratory testing may be performed based on symptomatic presentation or for screening of asymptomatic people. Confirmation of SARS-CoV-2 infection is typically by nucleic acid amplification tests (NAAT), which requires specialized equipment and training and may be particularly challenging in resource-limited settings. NAAT may give false-negative results due to timing of sample collection relative to infection, improper sampling of respiratory specimens, inadequate preservation of samples, and technical limitations; false-positives may occur due to technical errors, particularly contamination during the manual real-time polymerase chain reaction (RT-PCR) process. Thus, clinical presentation, contact history and contemporary phyloepidemiology must be considered when interpreting results. Several sample-to-answer platforms, including high-throughput systems and Point of Care (PoC) assays, have been developed to increase testing capacity and decrease technical errors. Alternatives to RT-PCR assay, such as other RNA detection methods and antigen tests may be appropriate for certain situations, such as resource-limited settings. While sequencing is important to monitor on-going evolution of the SARS-CoV-2 genome, antibody assays are useful for epidemiologic purposes. The ever-expanding assortment of tests, with varying clinical utility, performance requirements, and limitations, merits comparative evaluation. We herein provide a comprehensive review of currently available COVID-19 diagnostics, exploring their pros and cons as well as appropriate indications. Strategies to further optimize safety, speed, and ease of SARS-CoV-2 testing without compromising accuracy are suggested. Access to scalable diagnostic tools and continued technologic advances, including machine learning and smartphone integration, will facilitate control of the current pandemic as well as preparedness for the next one.

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.

Immune system: development and acquisition of immunological competence

OBJECTIVES

To describe the ontogeny of the immune system and the adaptive mechanisms of the immune system in the neonatal period, with an emphasis on transplacental antibody transport and breastfeeding.

SOURCE OF DATA

Non-systematic literature review in the PubMed database.

SUMMARY OF THE FINDINGS

The last two decades have witnessed a great advance in the knowledge of the immune system since conception. Several investigation tools have provided insight on phenomena that were previously inadequately understood. Still expanding, the functional and molecular investigation of various aspects of the immune system will make it possible to understand how intra-uterus maternal-fetal exchanges, the maternal microbiota interacting with the fetus and newborn, and the acquisition of immunological competence occur in healthy and disease scenarios.

CONCLUSIONS

In-depth knowledge of the development of the immune system and of the adaptive mechanisms that allow a safer transition to the extrauterine environment are fundamental components of optimizing maternal and young infant vaccination, as well as the strategies associated with full postnatal development, and the early diagnosis and treatment of innate errors of immunity.