Antibodies In Milk Research Articles

IgG and IgA Antibodies Post SARS-CoV-2 Vaccine in the Breast Milk and Sera of Breastfeeding Women.

The COVID-19 pandemic has carried massive global health and economic burden that is currently counteracted by a challenging anti-COVID-19 vaccination campaign. Indeed, mass vaccination against COVID-19 is expected to be the most efficacious intervention to mitigate the pandemic successfully. The primary objective of the present study is to test the presence of neutralizing anti-SARS-CoV-2 antibodies (IgA and IgG) in the breast milk and sera samples from vaccinated women at least 20 days after the complete vaccine cycle. A secondary aim is to compare the IgG antibodies level in maternal serum and breast milk. The third target is to evaluate the presence of the IgG antibodies in breast milk after several weeks from the vaccination. Finally, we collected information on the health status of infants in the days following maternal vaccination. Forty-two mothers were enrolled in the study. Thirty-six received the Pfizer/BioNTech vaccine, four the Astra Zeneca vaccine, one the Moderna vaccine and another woman Astra Zeneca in the first dose and Pfizer/BioNTech in the second dose. All 42 milk samples confirmed the presence of anti-SARS-CoV-2 IgG, and none showed IgA presence. Regarding the matched 42 sera samples, 41 samples detected IgG presence, with one sample testing negative and only one positive for seric IgA. None of the 42 infants had fever or changes in sleep or appetite in the seven days following the maternal vaccination. The level of IgG antibodies in milk was, on average, lower than that in maternal serum. According to our analysis, the absence of IgA could suggest a rapid decrease after vaccination even if frequent breastfeeding could favour its persistence. IgG were present in breast milk even 4 months after the second vaccine dose. Information on the immunological characteristics of breast milk could change mothers’ choices regarding breastfeeding.

A rapid phage assay for detection of viable Mycobacterium avium subsp. paratuberculosis in milk

Paratuberculosis is an incurable gastroenteritis among ruminants that is promoted by Mycobacterium avium subsp. paratuberculosis (MAP), an acid-fast mycobacterium. To accelerate the detection of viable pathogen, a conventional (peptide mediated magnetic separation: PMS) and novel (phage-bead qPCR: PBQ) phage based assay was optimized. A superior limit of detection (LOD) of 10 MAP per 10 mL milk was suggested for PBQ compared to 100 cells/10 mL for PMS-phage assay. Via PBQ, viable MAP was found in 48.78% out 41 unpasteurized sheep and goat milk samples. Sheep milk samples (n = 29) that were tested by PMS-phage assay contained no viable MAP. The absence of viable MAP in milk collected from 21 of the recent sheep animals was also confirmed by PBQ after a 2-week gap. Although, the two phage assays comparably detected no viable MAP in the milk samples, MAP DNA and antibodies against MAP were recognized in milk and sera of some of these animals within two instances of sampling representing that some sheep animals were MAP shedders. In conclusion, PBQ and PMS-phage could be promising methods for the assessment of MAP viability in milk samples. However, PBQ was privileged over the PMS-phage assay due to the lower LOD, rapidity, higher sensitivity, lack of need to M. smegmatis and consequent virucidal treatment that are essential in PMS-phage assay for making lawn and inactivation of exogenous mycobacteriophages respectively.

Milk Antibody Response after 3rd Dose of COVID-19 mRNA Vaccine and SARS-CoV-2 Breakthrough Infection and Implications for Infant Protection

Milk Antibody Response after 3rd Dose of COVID-19 mRNA Vaccine and SARS-CoV-2 Breakthrough Infection and Implications for Infant Protection

Milk Antibody Response After 3rd Dose of COVID-19 mRNA Vaccine and SARS-CoV-2 Breakthrough Infection and Implications for Infant Protection

Milk Antibody Response After 3rd Dose of COVID-19 mRNA Vaccine and SARS-CoV-2 Breakthrough Infection and Implications for Infant Protection

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.

Frequency of Neospora caninum-specific antibodies in bulk milk from dairy farms from Mar y Sierras Dairy Basin, Argentina.

The aim of this study was to describe the prevalence of Neospora caninum based on the detection of specific antibodies in bulk tank milk (BTM) from dairy cattle farms in the Mar y Sierras Basin by using an enzyme-linked immunosorbent assay (ELISA). A total of 98 BTM samples from 49 dairy farms were collected during autumn and spring of 2019. Additionally, 147 paired individual milk and serum samples were collected from two dairy farms to assess the prevalence within-herd by ELISA and indirect fluorescent antibody test (IFAT, serum samples). Additionally, 12 individual serum samples were also assessed to test the agreement between IFAT and ELISA (total serum samples 159). Noteworthy, 100 and 91.84% of 49 dairy farms were positive in the BTM in autumn and spring, respectively. For the within-herd individual samples, a good agreement between serum and milk results was obtained for ELISA and IFAT (0.86-0.90). This is the first study in Argentina in which milk samples were tested to determine the N. caninum infection status at herd and within-herd levels in dairy farms, providing a base for further research.

Functional Antibodies Against SARS-CoV-2 Receptor Binding Domain Variants with Mutations N501Y or E484K in Human Milk from COVID-19-Vaccinated, -Recovered, and -Unvaccinated Women.

Background: New variants are evolving in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and receptor binding domain (RBD) mutations have been associated with a higher capacity to evade neutralizing antibodies (NAbs). We aimed at determining the impact of COVID-19 vaccine and infection on human milk antibody titers and activity against the RBD mutations from SARS-CoV-2 variants of concern. Materials and Methods: Milk samples were collected from 19 COVID-19 vaccinated women, 10 women who had a positive COVID-19 PCR test, and 13 unvaccinated women. The titers and NAbs of secretory IgA (SIgA)/IgA, secretory IgM (IgM)/IgM, and IgG against SARS-CoV-2 RBD with mutations N501Y or E484K were measured by using ELISA and a surrogate virus neutralization assay. Results: The titers of human milk IgG against N501Y were higher in the COVID-19 vaccine group than in the no-vaccine group but comparable with the COVID-19 PCR group. Other antibody titers did not differ between the three groups. The titers of SIgA/IgA were higher than those of SIgM/IgM and IgG in all three groups. The titers of SIgM/IgM and the inhibition of NAbs were higher against the mutation E484K than N501Y. Milk NAb did not differ between the three groups, but the inhibition of NAb against binding of the two mutant RBD proteins to their receptor was higher in the COVID-19 vaccine and PCR groups than in milk from prepandemic women. Conclusions: COVID-19 vaccination and exposure of mothers to SARS-CoV-2 influenced the titers and NAbs in breast milk against the variants of concern.

Association of Human Milk Antibody Induction, Persistence, and Neutralizing Capacity With SARS-CoV-2 Infection vs mRNA Vaccination

Long-term effect of parental COVID-19 infection vs vaccination on human milk antibody composition and functional activity remains unclear. To compare temporal IgA and IgG response in human milk and microneutralization activity against SARS-CoV-2 between lactating parents with infection and vaccinated lactating parents out to 90 days after infection or vaccination. Convenience sampling observational cohort (recruited July to December 2020) of lactating parents with infection with human milk samples collected at days 0 (within 14 days of diagnosis), 3, 7, 10, 28, and 90. The observational cohort included vaccinated lactating parents with human milk collected prevaccination, 18 days after the first dose, and 18 and 90 days after the second dose. COVID-19 infection diagnosed by polymerase chain reaction within 14 days of consent or receipt of messenger RNA (mRNA) COVID-19 vaccine (BNT162b2 or mRNA-1273). Human milk anti-SARS-CoV-2 receptor-binding domain IgA and IgG and microneutralization activity against live SARS-CoV-2 virus. Of 77 individuals, 47 (61.0%) were in the infection group (mean [SD] age, 29.9 [4.4] years), and 30 (39.0%) were in the vaccinated group (mean [SD] age, 33.0 [3.4] years; P = .002). The mean (SD) age of infants in the infection and vaccinated group were 3.1 (2.2) months and 7.5 (5.2) months, respectively (P < .001). Infection was associated with a variable human milk IgA and IgG receptor-binding domain-specific antibody response over time that was classified into different temporal patterns: upward trend and level trend (33 of 45 participants [73%]) and low/no response (12 of 45 participants [27%]). Infection was associated with a robust and quick IgA response in human milk that was stable out to 90 days after diagnosis. Vaccination was associated with a more uniform IgG-dominant response with concentrations increasing after each vaccine dose and beginning to decline by 90 days after the second dose. Vaccination was associated with increased human milk IgA after the first dose only (mean [SD] increase, 31.5 [32.6] antibody units). Human milk collected after infection and vaccination exhibited microneutralization activity. Microneutralization activity increased throughout time in the vaccine group only (median [IQR], 2.2 [0] before vaccine vs 10 [4.0] after the first dose; P = .003) but was higher in the infection group (median [IQR], 20 [67] at day 28) vs the vaccination group after the first-dose human milk samples (P = .002). Both IgA and non-IgA (IgG-containing) fractions of human milk from both participants with infection and those who were vaccinated exhibited microneutralization activity against SARS-CoV-2. In this cohort study of a convenience sample of lactating parents, the pattern of IgA and IgG antibodies in human milk differed between COVID-19 infection vs mRNA vaccination out to 90 days. While infection was associated with a highly variable IgA-dominant response and vaccination was associated with an IgG-dominant response, both were associated with having human milk that exhibited neutralization activity against live SARS-CoV-2 virus.

First detection of anti-Toxoplasma gondii antibodies in domestic goat's serum and milk during lactation in China

Goat milk is considered as one of the most suitable substitute for human milk, especially for children, the aged and those with cow milk allergies. Consumption of raw or unpasteurized goat milk has been known to be a potential route of Toxoplasma gondii infection for human beings. However, no studies have been carried out to detect T. gondii in goat milk in China. Thus, this stuy was firstly carried out to detect T. gondii IgG antibody in domestic goat's serum and milk during lactation by a commercial validated ELISA kit in China. In total, 10.49% (66/629) serum samples and 9.70% (61/629) milk samples randomly collected from Shandong and Jilin provinces were seropositive for anti-T. gondii IgG, respectively. A high correlation of S/P% value was obtained between serum and milk samples (Spearman's coefficient = 0.891, p-value <0.001 and Kendall's tau = 0.724, p-value < 0.001). Statistical analysis showed that history of abortion, source of water and source of fodder were considered to be highly related to the T. gondii infection in the investigated domestic goats. The present results provide important information for the control and prevention of toxoplasmosis in goats and human beings in China.

Detection of SARS-CoV-2 IgG antibodies in breast milk and serum of immunized lactating mothers.

As coronavirus disease 2019 (COVID-19) continuous to spread, the transfer of maternal anti severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies via lactation is an important source of immunity innewborns that requires more comprehensive studies toimprove vaccine options in these candidates. The aim of this study was to evaluate SARS-CoV-2 spike protein antibodies against COVID-19 in breast milk and serum oflactating mothers post vaccination and to establish a correlation between both. Hundred and eighty lactating mothers were included in this cross sectional cohort study conducted at Rehman Medical Institute, Peshawar. We described the immunogenicity 21days after the booster dose of vaccine in 21 patients. Breast Milk and serum specimens were collected and investigated for SARS-CoV-2 spike protein antibodies by consuming electro-chemiluminescence immunoassay (Elecsys Anti-SARS-CoV-2S Roche, Switzerland). One-hundred percent of patients revealed robust positive findings to SARS-CoV-2 spike proteins antibodies in breast milk and 85 percent in serum, i.e.,>0.8IU/mL. Our study shows that lactating mothers can mount robust immune reactions against SARS-CoV-2 post vaccination. All participants had significantly higher antibody titers against SARS-CoV-2 after vaccination. Participants had antibody titers one scale higher post vaccination than pre vaccination. A significant correlation was found between SARS-CoV-2 antibodies in milk and serum. Constant monitoring of antibodies titers is estimated to attain significant humoral immunity against SARS-CoV-2 infection.

SARS-CoV-2 Antibodies in Breast Milk After Vaccination.

Passive and active immunity transfer through human milk (HM) constitutes a key element in the infant's developing immunity. Certain infectious diseases and vaccines have been described to induce changes in the immune components of HM. We conducted a prospective cohort single-institution study from February 2 to April 4, 2021. Women who reported to be breastfeeding at the time of their coronavirus disease 2019 (COVID-19) vaccination were invited to participate. Blood and milk samples were collected on day 14 after their second dose of the vaccine. Immunoglobulin G (IgG) antibodies against nucleocapsid protein as well as IgG, immunoglobulin M and immunoglobulin A (IgA) antibodies against the spike 1 protein receptor-binding domain against severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2 RBD-S1) were analyzed in both serum and HM samples. Most of the participants (ie, 94%) received the BNT162b2 messenger RNA COVID-19 vaccine. The mean serum concentration of anti-SARS-CoV-2 RBD-S-IgG antibodies in vaccinated individuals was 3379.6 ± 1639.5 binding antibody units per mL. All vaccinated study participants had anti-SARS-CoV-2 RBD-S1-IgG, and 89% of them had anti-SARS-CoV-2 RBD-S-IgA in their milk. The antibody concentrations in the milk of mothers who were breastfeeding 24 months were significantly higher than in mothers with breastfeeding periods <24 months (P < .001). We found a clear association between COVID-19 vaccination and specific immunoglobulin concentrations in HM. This effect was more pronounced when lactation periods exceeded 23 months. The influence of the lactation period on immunoglobulins was specific and independent of other variables.

Breastfeeding and the developmental origins of mucosal immunity: how human milk shapes the innate and adaptive mucosal immune systems.

Breastfeeding provides passive immunity while the neonatal immune system matures, and may also protect against chronic immune-mediated conditions long after weaning. This review summarizes current knowledge and new discoveries about human milk and mucosal immunity. New data suggest that certain microbes in maternal milk may seed and shape the infant gut microbiota, which play a key role in regulating gut barrier integrity and training the developing immune system. Human milk oligosaccharides, best known for their prebiotic functions, have now been shown to directly modulate gene expression in mast and goblet cells in the gastrointestinal tract. Epidemiologic data show a reduced risk of peanut sensitization among infants breastfed by peanut-consuming mothers, suggesting a role for milk-borne food antigens in tolerance development. Cross-fostering experiments in mice suggest the soluble Toll-like receptor 2, found in human milk, may be critical in this process. Finally, interest in human milk antibodies surged during the pandemic with the identification of neutralizing severe acute respiratory syndrome coronavirus 2 antibodies in maternal milk following both natural infection and vaccination. Human milk provides critical immune protection and stimulation to breastfed infants. Understanding the underlying mechanisms could identify new therapeutic targets and strategies for disease prevention across the lifespan.

COVID-19 mRNA vaccine and antibody response in lactating women: a prospective cohort study

BackgroundImmunological protection via breastfeeding is well known. The immunological profile of human milk changes during lactation. No clinical trials have been conducted in lactating women with the newest mRNA vaccines against SARS- CoV-2. A Few studies have shown the presence of antibodies in breastmilk after vaccination. The aim of this work is to study possible antibodies transfer via breastmilk and also the immunological characteristics of lactating women compared to non-lactating women, after using the BNT162b2 Pfizer vaccine.MethodsThis is a prospective cohort study with a convenience homogenous sample of 24 healthcare workers (14 lactating and 10 non-lactating women) enrolled at the time of COVID-19 vaccination. Clinical data was registered in a questionnaire. Titers of SARS-CoV-2 spike IgG, IgA and IgM were quantified in post vaccination blood and human milk. Antibody quantification was performed by an in-house ELISA to SARS-CoV-2 trimeric spike protein.ResultsAll women showed immunity after vaccination with positive antibodies for IgM, IgA and IgG antibodies. The dominant serum antibody response was IgG. Modest levels of antibodies in breastmilk of lactating mothers were observed in this study, especially IgG in 42.9%. There was a moderate association between higher titers of IgG and a longer duration of breastfeeding (R= 0.55, p=0.041).ConclusionsEvidence of antibody transfer in human milk after COVID-19 vaccination is scarce. The presence of antibodies in human milk is reported, but immunization through breastfeeding is still to be established.

One common enemy, a pandemic, uniting interdisciplinary teams

One common enemy, a pandemic, uniting interdisciplinary teams

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

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

Induction of SARS-CoV-2-Specific IgG and IgA in Serum and Milk with Different SARS-CoV-2 Vaccines in Breastfeeding Women: A Cross-Sectional Study in Northern Spain.

Breastfeeding mothers were excluded from the clinical trials conducted for vaccines against SARS-CoV-2. Since the start of the vaccination, some doubts have arisen regarding its compatibility with breastfeeding. The aim of this study was to analyse the presence of anti-SARS-CoV-2 antibodies in breast milk and serum (IgG and IgA) of vaccinated breastfeeding women. The main variables of the observational study were: adverse related events after vaccination and determination of the presence of IgG and IgA isotypes antibodies in serum and in breast milk of vaccinated women against the SARS-CoV-2 antigens. Results: 110 breastfeeding mothers were included; 70 women (63.6%) were vaccinated with two doses of BNT162b2, 20 women (18.2%) with two doses of mRNA-1273, and 20 women (18.2%) with a single dose of ChAdOx1-S. Regarding adverse reactions and vaccine safety, 38 women had no adverse reactions; 20 (18.2%) had general malaise or adenopathies; 10 (9.1%) had a headache; and 7 (6.4%) had fever. When analysing IgG antibodies, significantly higher levels of antibodies were found in serum and breast milk from mothers vaccinated with BNT162b2 or mRNA-1273 vs. ChAdOx1-S (p < 0.001 and p = 0.001, respectively). Analysing IgA antibodies, significant differences were found when comparing mean values in serum from mothers vaccinated with BNT162b2 or mRNA-1273 vs. ChAdOx1-S (0.12, 0.16, and 0.02, respectively; p < 0.001) and breast milk of mothers vaccinated when comparing BNT16b2 vs. ChAdOx1-S. All vaccinated breastfeeding mothers had serum anti-S1 IgG antibodies in response to vaccination against SARS-CoV-2, regardless of the commercial vaccine administered. Conclusions: the anti-SARS-CoV-2 vaccines were well tolerated by the mothers and the breastfed infant. In addition, breastfeeding mothers offer their infants IgA and IgG isotype antibodies directed against SARS-CoV-2 protein S in breast milk.

Quantification of Specific Antibodies Against SARS-CoV-2 in Breast Milk of Lactating Women Vaccinated With an mRNA Vaccine

The COVID-19 pandemic has raised questions among individuals who are breastfeeding, both because of the possibility of viral transmission to infants during breastfeeding and, more recently, of the potential risks and benefits of vaccination in this specific population. Previous studies have reported the presence of anti–SARS-CoV-2 antibodies in breast milk of COVID-19–infected lactating women,1 and recently several studies have demonstrated the passage of postvaccine antibodies through breast milk in women vaccinated with novel mRNA-based vaccines.1,2 In the present study, conducted between February and March 2021 at Parc Sanitari Sant Joan de Deu, an urban hospital in Spain, we sought to characterize the levels of specific SARS-CoV-2 antibodies in the breast milk of mRNA-vaccinated women across time, as well as their correlation with serum antibody levels.

Seroprevalence of pestivirus infections is low in Belgian small ruminant flocks and is significantly associated with the presence of cattle

A study was implemented to estimate the pestivirus seroprevalence in sheep and goats in Belgium, to identify circulating species and to check for a potential association between seropositivity of small ruminants and presence of cattle in the same farm. It was based on the testing of serum samples and bulk tank milk samples (BTM) collected in sheep and goat flocks in 2018–2019 all over the country. 7460 serum samples collected from 410 flocks were tested by a commercial ELISA able to detect antibodies (Ab) against Border Disease Virus (BDV), and Bovine Viral Diarrhea Virus (BVDV). BTM samples (n = 144) were collected from dairy flocks in November 2019 and tested with the same Ab ELISA. ELISA positive serum samples were also tested by virus neutralization test (VNT) for neutralizing antibodies against BDV, BVDV-type1 and BVDV-type2. Virological tests (RT-PCR) were performed on pools of serum samples from pestivirus-exposed flocks with at least two seropositive animals and on all Antibody-positive BTM samples. Information about serum and milk samples (identification, test results, farm of origin and location, presence of cattle) were gathered in animal-level and farm-level databases.Based on this study, the apparent animal seroprevalence for pestiviruses in small ruminant flocks in Belgium in 2018 was estimated to be 0.87 % (95 % C.I. [0.68 %–1.11 %]). The prevalence of flocks exposed to pestivirus (i.e. with at least one seropositive animal) was estimated to be 8.5 % (95 % C.I. [6.4 % - 11.6 %]). In exposed flocks, the average within-flock seroprevalence was 9.9 %. In dairy sheep and goats, the estimated proportion of exposed flocks in 2019, based on the detection of pestivirus antibodies in the bulk tank milk, was 9.7 % [5.9 %–15.7 %]. All PCR tests were negative, indicating the likely absence of active pestivirus circulation in these flocks. Although the observed pestivirus seroprevalence was found to be low in Belgian small ruminants, this study also showed, based on VNT results, that they are exposed to several pestivirus species: BDV, BVDV-1 and BVDV-2. 22.4 % of the farms included in the serological survey were holding both a small ruminant flock and a cattle herd, hence with a potential risk of contact between the two species. There was a significant positive association between pestivirus seropositivity in the sheep/goat flocks and the presence of a cattle herd in the same farm (OR = 2.42 (95 %C.I. [1.18–4.94]) but this association was not found for Ab-positive BTM in dairy flocks.

Human Milk Antibodies Against SARS-CoV-2: A Longitudinal Follow-Up Study.

Human milk contains antibodies against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) following Coronavirus Disease 2019 (COVID-19). These antibodies may serve as protection against COVID-19 in infants. However, the evolution of these human milk antibodies over time is unclear. To elucidate the evolution of immunoglobulin A (IgA) against SARS-CoV-2 in human milk after a SARS-CoV-2 infection. This longitudinal follow-up study included lactating mothers (N = 24) who had participated in the COVID MILK study. To assess the evolution of SARS-CoV-2 antibodies, serum and human milk samples were collected 14-143 days after the onset of clinical symptoms related to COVID-19. Enzyme-Linked ImmunoSorbent Assay was used to detect antibodies against the ectodomain of the SARS-CoV-2 spike protein. SARS-CoV-2 antibodies remain present up to 5 months (143 days) in human milk after onset of COVID-19 symptoms. Overall, SARS-CoV-2 IgA in human milk seems to gradually decrease over time. Human milk from SARS-CoV-2 convalescent lactating mothers contains specific IgA antibodies against SARS-CoV-2 spike protein up to at least 5 months post-infection. Passive viral immunity can be transferred via human milk and may serve as protection for infants against COVID-19.

SARS-CoV-2 Antibodies Detected in Mother's Milk Post-Vaccination.

BackgroundThe Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic has infected over 127 million people worldwide, with almost 2.8 million deaths at the time of writing. Since no lactating individuals were included in initial trials of vaccine safety and efficacy, research on SARS-CoV-2 vaccination in lactating women and the potential transmission of passive immunity to the infant through mother’s milk is needed to guide patients, clinicians, and policy makers on whether to recommend immunization during the worldwide effort to curb the spread of this virus.Research Aims(1) To determine whether SARS-CoV-2 specific immunoglobins are found in human milk after vaccination, and (2) to characterize the time course and types of immunoglobulins present.MethodsA longitudinal cohort study of lactating women (N = 7) who planned to receive both doses of the Pfizer-BioNTech or Moderna SARS-CoV-2 vaccine between December 2020 and January 2021 provided milk samples. These were collected pre-vaccination and at 11 additional timepoints, with the last sample at 14 days after the second dose of vaccine. Samples were analyzed for levels of SARS-CoV-2 specific immunoglobulins A and G (IgA and IgG).ResultsWe observed significantly elevated levels of SARS-CoV-2 specific IgG and IgA antibodies in human milk beginning approximately 7 days after the initial vaccine dose, with an IgG-dominant response.ConclusionsMaternal vaccination results in SARS-CoV-2 specific immunoglobulins in human milk that may be protective for infants.