Antibodies and inflammatory markers are pervasive in colostrum of SARS-CoV-2 infected women

A recent study, currently available on the medRxiv* preprint server, is among the first to reveal the presence of antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in colostrum and to demonstrate elevated cytokine levels in colostrum from women exposed to the virus.

Current recommendations endorse breastfeeding for mothers infected with SARS-CoV-2, a causative agent of coronavirus disease (COVID-19), since the benefits of mother's milk are believed to outweigh potential risks of viral transmission to the infant.

Still, as the number of both pregnant and lactating women with SARS-CoV-2 increases, there is a dire need to expand limited yet existent research on immune response and specific antibodies in breast milk of infected women, but also in the colostrum (i.e., a nutrient-rich milky fluid produced in late pregnancy and few days after birth).

Available medical literature is pointing towards the conclusion that the transfer of cytokines via breast milk may indeed impact an infant's immune system, bestowing in turn protection against various allergies and infectious disease agents.

Furthermore, multiple studies to date have described a substantial increase in inflammatory cytokines in the bronchoalveolar lavage fluid and serum of COVID-19-infected individuals. Thus far, there are no published reports on the cytokine profiles in breast milk of women with COVID-19, we still cannot draw any parallels.

Consequently, researchers from the University of Massachusetts decided to appraise the presence of antibodies specific to SARS-CoV-2, as well as corresponding cytokines in colostrum from women who tested positive for the virus.

Antibodies and cytokines in colostrum

Between March and September 2020, the researchers obtained bilateral colostrum samples that were hand-expressed on spot cards within 48 hours of delivery from 15 new mothers who had previously tested positive for SARS-CoV-2, as well as one new mother who previously tested negative.

Furthermore, six participants also provided liquid bilateral colostrum (i.e., 5-10 milliliters from each breast into the container) within two days after providing the spot card samples. For comparison purposes, archived bilateral colostrum samples that were collected from 8 women (in the period between 2011 and 2013) were utilized as pre-COVID-19 controls.

All samples were tested for their reactivity to the receptor-binding domain of the SARS-CoV-2 spike glycoprotein with the use of enzyme-linked immunosorbent assay (ELISA) that captures IgG, IgM, and IgA antibodies.

Moreover, ten inflammatory cytokines (interferon-gamma, tumor necrosis factor-alpha, IL-1 beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13) were appraised with the use of a novel multiplex electrochemiluminescent sandwich assay.

Reactivity results

This study has shown that bilateral colostrum samples showed IgG, IgA, and IgM reactivity to the receptor-binding domain of SARS-CoV-2 in 73%, 73%, and 33% of the 15 COVID-19 mothers, respectively. On the other hand, colostrum samples from only two of the eight pre-pandemic controls had IgG and IgA reactivity to the receptor-binding domain.

In addition, COVID-19 mothers exhibited significantly higher levels of 9 of the 10 inflammatory markers (all except interferon-gamma) in comparison to the pre-COVID-19 controls. It has to be noted that analogous results were obtained with both the spot card-eluates and liquid samples.

"While there are some conflicting reports, the lack of increased interferon-gamma expression associated with COVID-19 is consistent with our findings in colostrum and needs further investigation", say study authors in this medRxiv paper.

No barriers for breastfeeding

In a nutshell, colostrum samples that were archived long before the pandemic were crucial controls for this study when used in conjunction with the analysis of bilateral samples. The similarities between results from the spot card and the liquid colostrum demonstrate the value of the spot card collection method.

"The evolution and duration of the antibody response, as well as dynamics of the cytokine response, remain to be determined," caution study authors. "Our results also indicate that future large-scale studies can be conducted with milk easily collected on paper spot cards," they add.

In any case, the detection of SARS-CoV-2-specific antibodies in women with diverse COVID-19 disease presentations provides objective data in favor of initiating breastfeeding, regardless of SARS-CoV-2 infection. These findings also facilitate future large-scale studies that may use milk collected on paper spot cards.

*Important Notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Journal reference:
Dr. Tomislav Meštrović

Written by

Dr. Tomislav Meštrović

Dr. Tomislav Meštrović is a medical doctor (MD) with a Ph.D. in biomedical and health sciences, specialist in the field of clinical microbiology, and an Assistant Professor at Croatia's youngest university - University North. In addition to his interest in clinical, research and lecturing activities, his immense passion for medical writing and scientific communication goes back to his student days. He enjoys contributing back to the community. In his spare time, Tomislav is a movie buff and an avid traveler.


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  1. Carlos N Misty Christian Carlos N Misty Christian United States says:

    I actually am pregnant and due in April, and I have several children & breastfed them all. I would like to say that I have been taught by my lactation consultant, previous years, that if I am sick that my child would receive my antibodies of whatever I had come down with and I will add that I have had flu, etc bugs that my children either didn't get or they were not sick really at all with the exception of maybe a mild temp bc of the antibodies I gave them. I have been really sick a couple of times, fever and all, with a couple of them while breastfeeding and they didn't get it. I don't know 100 percent that I got the cv19 this year but I did experience some of the symptoms that they reported, so I did quarantine myself, and I did get better. I am still pregnant so I know that whatever I had, Father was watching over us, and gave it to me so the baby would be protected, and I know that when my breastmilk comes in that the baby will be just fine. I have complete and 'udder' faith that I have great immunity because I have never had any flu vaccine but have been sick with what I am pretty sure was flu before. My children and I are in great health currently, one of them being an adult and the others still young ranging from 17 all the way down to nearly 3,(in May), so I am pretty confident that I know what I am talking about, even though I don't have any degree in healthcare.

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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