Covid messenger RNA vaccines were not detected in breast milk. This is what emerges from a small study by the University of California San Francisco, which provides positive data for the safety of immunization of pregnant and lactating women. The authors of the study published in ‘Jama Pediatrics’ analyzed the breast milk of 7 women after they were given the vaccine and found no trace of the shield product. The research thus offers the first direct data on the safety of the vaccine in breastfeeding and, the experts note, could help to “dispel the concerns” of those who refuse prophylaxis or choose to stop breastfeeding their baby because of the fear that the vaccine could altering human milk.
The products examined in the study are those from Pfizer and Moderna, both of which contain mRna. The World Health Organization (WHO), the authors recall, recommends that breastfeeding people be vaccinated, and the Academy of Breastfeeding Medicine said there is little risk of vaccine nanoparticles or mRna entering breast tissue. or are transferred into milk, which theoretically could affect infant immunity. “Our results – comments the corresponding author Stephanie L. Gaw (Ucsf) – reinforce the current recommendations according to which these vaccines are safe during breastfeeding”.
And indeed, adds lead author Yarden Golan, “we did not detect the mRna associated with the vaccine in any of the milk samples tested. This provides experimental evidence” confirming what has already been indicated. The study was conducted from December 2020 to February 2021. The average age of the mothers was 37.8 years and their children ranged in age from one month to three years. Milk samples were collected before vaccination and at various times up to 48 hours after vaccination. The study has small numbers. Now, the researchers conclude, more clinical data from larger populations are needed to better estimate the effect of vaccines on lactation outcomes.