Immunity and COVID

The passive immunity in newborn babies is built through the antibody obtained by the transfer via the placenta and the breast milk following natural infection and immunization. The immune systems of newborns are still in the developing and immature stage; hence passive immunity plays a very essential and important for protecting them against neonatal infectious diseases against different pathogenic microorganisms.¹

For newborns, breast milk is the gold standard and it is a food with complete nutritional needs of the infant and varies between mothers. Mainly the breast milk contains multipotent stem cells, hormones, immunoglobulins, and bacteria. It also has human milk oligosaccharides (HMOs), which provide several protective biological functions such as immune-modulation and protection against disease.² Studies have shown that sIgA, is the most abundant antibody found in breast milk providing protection against different pathogens. The previous infection of the mother determines the specificity of sIgA, which explains the low rates of infection or milder symptoms of the infected breastfed infants of SARS-CoV–infected mothers. Also, the cytokines and growth factors present in the milk boost the infant’s immune system and keep a balance between the anti-inflammatory and pro-inflammatory cytokines, reducing the effect of  “cytokine storm” described in viral infections, such as H1N1 ‘swine flu’ and H5N1 ‘bird flu’.³

Recent studies among pregnant and lactating women reported that the COVID-19 vaccine in pregnant and lactating women enhanced the SARS-CoV-2-antibodies production and was transported to infants through cord blood and breast milk. Vaccination and antibodies produced due to previous natural infection in women could induce antibody responses and T-cell responses against different infections and also against SARS-CoV-2.¹

According, to new research from the University of Florida, it was reported that the breast milk of lactating mothers vaccinated against COVID-19 contained a significant supply of antibodies that could protect nursing infants from the illness. The study was conducted between December 2020 and March 2021, when the Pfizer and Moderna vaccines first became available to health care workers. The study included 21 lactating health care workers who were never infected with COVID-19. Breast milk samples were tested thrice: before vaccination, after the first dose and after the second dose. Results from the study conclude that almost a hundredfold increase was observed in the antibody response in blood and breast milk after the second dose, proving that vaccinating mothers with COVID-19 vaccines could provide protection to the infant too.⁴

Some officials state that it is already established that expectant mother who is vaccinated against whooping cough and flu because these can be serious illnesses for infants, provide protection to the baby. Hence, routine vaccination of mothers against the virus could be helpful to protect in the future.⁴

Some research papers published in the journal Breastfeeding Medicine, strongly state that vaccinating pregnant or lactating women could help protect both mother and baby, and so vaccination with COVID-19 vaccine among this group should be encouraged.

References:

1. VDM. Breast Milk and Passive Immunity during the COVID-19 Pandemic. Front Immunol. 2021;Medolac Laboratories.Available from: Breast Milk and Passive Immunity during the COVID-19 Pandemic | Frontiers Research Topic (frontiersin.org)
2. Dessì A, Briana D, Corbu S, Gavrili S, Cesare Marincola F. Metabolomics of Breast Milk: The Importance of Phenotypes. 2018;8(4).
3. Vassilopoulou E, Feketea G, Koumbi L, Mesiari C, Berghea EC, Konstantinou GN. Breastfeeding and COVID-19: From Nutrition to Immunity. Frontiers in immunology. 2021;12:661806-.
4. Murray S. Breast milk of mothers who received COVID-19 vaccine contains antibodies that fight illness: Science News; 2021 [updated 24 August 2021.; cited 2021 12-Sep-21]. Available from: https://www.sciencedaily.com/releases/2021/08/210824104139.htm