Study shows COVID-19 specific antibodies most present in breastmilk of mRNA vaccinated women

by: Jen Warner

A study published by JAMA Pediatrics on March 14, 2022, found that antibodies capable of neutralizing COVID-19 are most present in the milk of breastfeeding mothers who have received two doses of an mRNA vaccine, thus providing maximum protection for both mother and child.

This new research comes after years of limited data on the efficacy of the COVID-19 vaccine for breastfeeding mothers and the immunity potential for their babies.

“Lactating women have been excluded from vaccination trials due to safety concerns,” said study author Dr. Britt van Keulen in an email interview. “As such, vaccination against COVID-19 has been discouraged for a long time in this specific group, resulting in a lack of knowledge on the effect of vaccinations on human milk.”

The Netherlands based study analyzed 1,650 human milk samples from 124 lactating mothers. Research concluded that COVID-19 specific antibodies were present in almost 100% of participants who received two doses of either the Pfizer-BioNTech vaccine or the Moderna vaccine, the two mRNA options presently available to the public.

Results for participants who opted for a vector-based vaccine were markedly different, with COVID-19 specific antibodies detected in 39% of those who received the AstraZeneca vaccine and in 48% of those who received the Johnson & Johnson vaccine.

The transferability of COVID-19 specific antibodies into breastmilk evident in this study adds to the long list of benefits that experts agree nursing already provides.

According to Cleveland Clinic, breastfed babies have stronger immune systems, fewer gastric issues, lower occurrences of respiratory illnesses and infections, reduced risk of sudden infant death syndrome (SIDS,) lower rates of infant mortality, and more.

As per their website, this is due to the abundance of “easily absorbed nutritional components, antioxidants, enzymes, immune properties, and live antibodies from mother” found in breastmilk. Once ingested, said milk lines the immature gastro-intestinal tract of the baby and prevents germs from passing through.

With four different vaccine options and a deep understanding of the advantages of breastmilk, researchers of this study aimed to provide guidance to future lactating mothers and healthcare providers alike in their COVID-19 vaccine decision making process.

Among those providers utilizing this guidance in their practice is certified birth and postpartum doula Lenamarie Gorski, owner of Birth With A Voice Doula Service.

“I will be encouraging all of my pregnant and/or lactating clients to get vaccinated to protect their babies,” Gorski said in an email interview. “Furthermore, I will be forwarding this research so they may make the informed choice to breastfeed during this pandemic to keep their babies safe until vaccine age.”

For one of Gorski’s clients, the science holds up. This client received the first two doses of the Moderna vaccine while pregnant and received her booster when her exclusively breastfeed twins were just 4 months old.

When COVID-19 came knocking with a positive diagnosis for all in their household, the babies never experienced so much as a sniffle.

“Human milk is remarkable in so many ways,” added Gorski. “The body that makes the baby then protects them from a virus they are too young to be vaccinated against.”

Full study findings can be viewed at https://jamanetwork.com/journals/jamapediatrics/fullarticle/2789947.

Dr. van Goudoevercan be reached at h.vangoudoever@amsterdamumc.nl.