August is all about lactation!  August 1-7 is World Breastfeeding* Week, August 8th - 14th is Native Breastfeeding Week, August 25th - 31st is Black Breastfeeding Week and in the USA,  the entire month recognized as National Breastfeeding Month. Today’s research review summarizes a study that examined nursing and the passage of COVID-19 antibodies from parents who received a COVI-19 vaccination after birth and during bodyfeeding.

Introduction

In the just published Presence of SARS-CoV-2 antibodies in lactating women and their infants following BNT162b2mRNA vaccine, Israeli researchers examined whether immunoglobulins (antibodies) to the COVID-19 virus would be present in the milk of lactating people who received the COVID-19 vaccine after birth and who were feeding their babies with their human milk.  The presence of these antibodies were also tested in the sera and oral mucosa (saliva) secretions of their newborns.

How was the study conducted

This study was conducted between December 2020 and April 2021 in Israel.  Lactating people who received the COVID-19 vaccination after they birthed were included in the study along with their newborns.  People who had COVID-19 previously, or been vaccinated prior to giving birth were excluded from the study.

Blood samples and human milk from the lactating people were obtained. Blood samples from the infants were also collected along with the infants’ saliva samples. The infant saliva samples were collected immediately after breast/chestfeeding, and additionally at 30, 90 and 150 minutes after the feeding.

Using a variety of testing protocols, the milk and serum samples were analyzed for SARS-CoV-2 IgG and IgA, the antibodies that protect against COVID-19.

What were the results

61 lactating people provided their milk and blood samples. All the maternal blood samples showed the presence of antibodies to COVID-19.  55 human milk samples also indicated that antibodies to COVID-19 were present.  The more antibodies that were present in a person’s blood sample corresponded with higher levels of antibodies present in their milk sample. Additionally, upon further testing it was found that 18 of 47 milk samples were found to neutralize the COVID-19 virus.

Five newborns’ oral mucosa were sampled and 60% of the samples showed the presence of COVID-19 antibodies.  The dried blood samples of 21 infants were also tested and were negative for COVID-19 antibodies.

Conclusion

In this longitudinal cohort study, lactating people who were vaccinated to COVID-19 after birth were found to have SARS CoV-2 IgG (antibodies to COVID-19) in milk samples. Half of those samples were able to neutralize COVID-19 infectivity.  Antibodies were present in the saliva of the sampled infants but not in their blood samples.  The researchers state that it may be suggestive that the infants of those people who were vaccinated after birth may acquire passive immunity to the COVID-19 virus.  As antibodies were not detected in the infants’ blood samples, the researchers concluded that vaccinating pregnant people with the COVID-19 vaccine may offer better protection via trans-placental passage of antibodies to the fetus than that protection received by bodyfeeding infants of parents vaccinated post birth.

Resources

Schwartz A, Nir O, Toussia-Cohen S, Leibovich L, Strauss T, Asraf K, Doolman R, Sharabi S, Cohen C, Sapir E, Lustig Y, Regev-Yochay G, Yinon Y, Presence of SARSCoV-2 antibodies in lactating women and their infants following BNT162b2mRNA vaccine, American Journal of Obstetrics and Gynecology (2021), doi: https://doi.org/10.1016/j.ajog.2021.07.016

*Note: While the term “breastfeeding” is used in the marketing of these promotional events, I want to acknowledge that people who lactate include many diverse populations who may breastfeed, chestfeed or bodyfeed or simply feed their babies human milk in another way.

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