New research has shown that women who are vaccinated against Covid-19 during pregnancy not only protect themselves against the virus, but are able to transfer immunity to their babies.
Transfer Of Immunity
The study, by the University of Massachusetts, measured the immune response to the COVID-19 mRNA vaccine in both breast milk and the stools of breastfed infants.
Prior to this, several preliminary studies have shown that women who receive an mRNA vaccine such as Moderna or Pfizer during pregnancy had Covid-19 antibodies in their umbilical cord blood.
Another also points to the presence of antibodies in their breastmilk, indicating that at least some immunity could be transferred to babies both before and after birth.
Lead author Vignesh Narayanaswamy, Ph.D., said:
This research is the first to detect SARS-CoV-2 antibodies in stool samples from infants of vaccinated mothers. This is really important because women want to know whether their babies have these antibodies, and our study shows that antibodies are being transferred via breast milk.
He added that this research could prove what the medical and scientific community have been hoping for, which is that vaccines could provide protective antibodies to fetuses.
A Case For Breastfeeding
Thirty lactating women from across the U.S. – most of them healthcare workers – were enrolled in the study. The participants were given the COVID-19 mRNA vaccine between January and April 2021.
Infant stool samples were collected 21 days after the mothers’ second vaccination. Pre-pandemic samples of breast milk, dried blood spots and infant stools were used as controls for the study. Narayanaswamy said:
Providing this compelling evidence is motivation for women to continue breastfeeding after they receive the vaccine.
The study, published in the journal Obstetrics & Gynaecology, also measured the antibody responses of the women to the various vaccines. The levels of antibodies correlated with the vaccine side effects the mother experienced.
Senior Author, Kathleen Arcaro explained:
Women who did feel sick from the vaccine was associated with greater antibodies in the infant stool. So you might have felt badly, but that was a benefit for your infant.