Discover Breastfeedings Newest Benefit

Dr. Hanadys Ale, Pediatric Immunologist and Allergist, JDCH Physician Newsletter Winter 2022

Mammals are the only organisms on the planet capable of feeding their offspring with milk from their breasts. This special milk is meticulously manufactured by the mother’s body to meet her baby’s unique needs. As the most evolved mammals on the face of the earth, we humans can make the conscious decision of nursing our babies or feeding them with formula instead. The decision to breastfeed is a very personal one, and the circumstances are unique to each mother and baby.

However, it is irrefutable that breastfeeding provides incomparable benefits for the health not only of babies, but their mothers as well. The properties of breast milk are just extraordinary. Breast milk contains an ideal balance of nutrients not found anywhere else. It has the perfect amount of fat, sugar, water, and protein that is needed for a baby's growth and development.

Additionally, it contains antibodies that provide immune protection early in life. Breastfeeding triggers biochemical reactions which allow immunologic substances to effectively defend the breastfed infant against numerous infectious diseases.

Ruth Petersen, MD, director of CDC’s Division of Nutrition, affirmed that breastfeeding “is the clinical gold standard for infant feeding and nutrition, with breast milk uniquely tailored to meet the health needs of a growing baby.”

According to the CDC: “Breastfeeding is an investment in health, not just a lifestyle decision.”1

Breastfed infants have a reduced risk of acquiring the following conditions:

  • Asthma
  • Obesity
  • Type 1 diabetes
  • Severe lower respiratory disease
  • Acute otitis media (ear infections)
  • Sudden infant death syndrome (SIDS)
  • Gastrointestinal infections (diarrhea/vomiting)
  • Necrotizing enterocolitis (NEC) for preterm infants

Breastfeeding can help lower a mother’s risk of the following conditions:

  • High blood pressure
  • Type 2 diabetes
  • Ovarian cancer
  • Breast cancer

My personal journey with breastfeeding after receiving an mRNA COVID-19 vaccine

I am a pediatric immunologist and allergist who has always been very pro-breastfeeding. That is why I made the decision to breastfeed my baby when it was my turn. My son, Alejandro, now 14 months old, was born in one of the peaks of the COVID-19 pandemic. This pandemic has changed many things, one of them being the value of breastfeeding.

Because of the COVID-19 pandemic, at least for me, breastfeeding took on a whole new connotation and benefit. Protecting my baby against COVID-19 by giving him my antibodies (acquired after vaccination) through my breastmilk became one of my biggest motivations to continue our breastfeeding journey.

I learned that I was pregnant with my son in late December 2019. Only a couple of months later our country was seeing the first cases of a global pandemic caused by the SARS-COV-2 virus. The fear of being infected with the new deadly virus while pregnant was overwhelming. After delivery of my son, the fear of my baby getting sick created even more trepidation.

However, I was very fortunate to have the opportunity to receive the first dose of the Pfizer mRNA COVID vaccine when he was just three months old.

“The knowledge that I would be creating antibodies against COVID after vaccination and then passing on my very own antibodies to my baby became one of my greatest incentives to continue breastfeeding despite the challenges that it entailed.”

At that time, there were no studies about breastfeeding and COVID specific antibodies in breastmilk after vaccination or infection with COVID. One of the questions asked in the vaccination pre-screening form was, “Are you pregnant or breastfeeding?” I was breastfeeding, yet eagerly received the vaccine without hesitation.

I had faith in my knowledge as a pediatric immunologist that I would produce antibodies that would pass to my baby. I was sure the studies proving the existence of protecting COVID-19 antibodies in breastmilk would start coming out soon. And they did.

Studies proving the presence of naturalizing COVID-19 antibodies in breast milk

Several reports have been published so far proving that breastfeeding mothers who have been either infected with COVID or received COVID vaccines have antibodies in their breast milk, which could help protect their babies. Below is a list of some of those studies and a brief summary of the main findings:

1. Characterization of SARS-CoV-2 RNA, Antibodies, and Neutralizing Capacity in Milk Produced by Women with COVID-192

The authors stated that: “milk produced by infected mothers is a beneficial source of anti-SARS-CoV-2 IgA and IgG and neutralizes SARS-CoV-2 activity.”

2. Antibodies Against SARS-CoV-2 in Human Milk: Milk Conversion Rates in the Netherlands3

This study found a high prevalence of antibodies in human milk, which might lead to passive immunity in many breastfed infants and may serve as protection against COVID-19.

3. COVID-19 Vaccine Response in Pregnant and Lactating Women: A Cohort Study4

The authors concluded that: “COVID-19 mRNA vaccines generated robust humoral immunity in pregnant and lactating women, with immunogenicity and reactogenicity similar to that observed in non-pregnant women. Vaccine-induced immune responses were significantly greater than the response to natural infection. Immune transfer to neonates occurred via placenta and breastmilk.”

4. SARS-Cov-2-Specific Antibodies in Breast Milk After COVID-19 Vaccination in Breastfeeding Women5

This study found robust secretion of SARS-CoV-2 specific IgA and IgG antibodies in breast milk for 6 weeks after vaccination. IgA secretion was evident as early as 2 weeks after vaccination followed by a spike in IgG after 4 weeks (a week after the second vaccine). Antibodies found showed strong neutralizing effects, suggesting a potential protective effect against infection in the infant.

Breastfeeding should always be encouraged, including those patients with current or past infections with COVID and in patients who have received the COVID vaccination.

In summary, breastfeeding has incredible benefits for both the lactating infant and the mother. The presence of COVID-19 antibodies in breastmilk adds an extra layer to the innumerable benefits of breastfeeding. Neutralizing antibodies against the SARS-CoV-2 virus have been found in breast milk suggesting the potential of protection against COVID in the infant.

Breastfeeding should be supported and encouraged by pediatricians, obstetricians and all medical personnel involved with the mother and her baby.

In the words of the U.S. Surgeon general: “Given the importance of breastfeeding on the health of mothers and children, it is critical that we take action to support breastfeeding. Women who choose to breastfeed face numerous barriers—only through the support of family, communities, clinicians, healthcare systems, and employers will we be able to make breastfeeding the easy choice”.


1 CDC: Breastfeeding | Why It Matters:

2 Pace RM, Williams JE, Järvinen KM, et al. Characterization of SARS-CoV-2 RNA, Antibodies, and Neutralizing Capacity in Milk Produced by Women with COVID-19. mBio. 2021;12(1):e03192-20. Published 2021 Feb 9. doi:10.1128/mBio.03192-20

3 Juncker HG, Romijn M, Loth VN, et al. Antibodies Against SARS-CoV-2 in Human Milk: Milk Conversion Rates in the Netherlands. J Hum Lact. 2021;37(3):469-476. doi:10.1177/08903344211018185

4 Gray KJ, Bordt EA, Atyeo C, et al. Coronavirus disease 2019 vaccine response in pregnant and lactating women: a cohort study. Am J Obstet Gynecol. 2021;225(3):303.e1-303.e17. doi:10.1016/j.ajog.2021.03.023

5 Perl SH, Uzan-Yulzari A, Klainer H, et al. SARS-CoV-2-Specific Antibodies in Breast Milk After COVID-19 Vaccination of Breastfeeding Women. JAMA. 2021;325(19):2013-2014. doi:10.1001/jama.2021.5782

About the Author

Ale, Hanadys Hanadys Ale, MD, is a pediatric immunologist and allergist at Joe DiMaggio Children's Hospital. She treats children with atopic diseases such as allergic rhinitis, allergic conjunctivitis, asthma, urticaria, eczema, contact dermatitis, food allergy, food protein induced enterocolitis (FPIES), Eosinophilic Esophagitis (EoE), drug allergy, venom allergy and anaphylaxis.  

Disclaimer: The ideas and opinions presented in this blog post do not reflect the ideas and opinions of Memorial Healthcare System.