A study conducted by researchers in the United States found no evidence to suggest that the messenger RNA (mRNA) present in the Pfizer-BioNTech and Moderna vaccines that protect against coronavirus infection may be 2019 (COVID-19) to human breast milk.
The team’s analysis found no vaccine-related mRNA in breast milk samples collected from six individuals up to 48 hours after receiving the vaccine with one of the vaccines.
Stephanie Gaw and colleagues from the University of California at San Francisco say the findings support recommendations from the World Health Organization (WHO) and the Academy of Breastfeeding Medicine (ABM) that people should individuals receiving mRNA-based vaccinations continue to breastfeed unbroken infants.
However, clinical data from larger numbers are needed to better estimate the impact of these vaccines on lactation results, adds the team.
A pre-printed version of the research paper can be found on the medRxiv* server, while the article is under peer review.
Distribution of mRNA-based vaccines has begun in several countries
Several countries have begun rolling out mVNA-based COVID-19 vaccines recently approved for emergency use.
These mRNAs are in these vaccine codes for a protein called “spike,” found on the surface of true respiratory coronavirus 2 (SARS-CoV-2) syndrome – the causative agent of COVID-19.
This spike is the main structure used by the virus to capture host cells and a key target of the neutral antibodies produced after vaccination.
However, phase 3 clinical trials of the currently administered Pfizer-BioNTech and Moderna vaccines did not include pregnant or lactating women, despite an increased risk of serious COVID-19 complications. in this population group.
As a result, no clinical data are available on the safety or efficacy of mRNA-based vaccines in this population.
The WHO advises that breastfeeding people should be vaccinated if they belong to a priority group such as health care workers and continue to breastfeed after receiving the vaccine. The ABM also states that there is little plausible risk of vaccine lipid fractions entering the bloodstream and breast augmentation or the transfer of nanoparticles or mRNA to breast milk.
However, some mothers have still opted out of vaccination, while others have opted to pump and dump breast milk for up to 72 hours after vaccination, and some have stopped breastfeeding altogether. .
What did the current study cover?
Human breast milk samples were collected from six individuals between 4 and 48 hours after vaccination with the Pfizer-BioNTech BNT162b2 (n = 5) vaccine or the Moderna mRNA-1273 vaccine (n = 1).
Total RNA was separated from the breast milk components, including cells, the surface and the fat content.
The gold standard method of SARS-CoV-2 detection – transverse-chain polymerase reverse chain (RT-qPCR) – has been tripled using primers that specifically target the spike-coded mRNA. vaccines.
The Moderna vaccine was “introduced” into pre-vaccination samples before RNA was administered to provide advanced control. Pre-vaccination samples that were not vaccinated were added as negative controls.
What did the team find?
The researchers found vaccine mRNA in the “spiked-in” pre-vaccine samples, with higher levels found in the fat cover portion.
However, milk samples collected from six individuals within 24 hours of vaccination and six serial milk samples collected at 4, 8, 22, 28, 33, and 48 hours after vaccination did not show any evidence of vaccine-related mRNA in any of the breast milk components tested.
What did the authors decide?
“We show here that the mRNA from COVID vaccines is not detected in human breast milk samples collected 4-48 hours after vaccination,” said Gaw and colleagues.
The researchers say the findings support recommendations from the WHO and ABM that lactating women who receive an mRNA-based vaccine will have their breasts unbroken.
However, “clinical data from larger numbers need to be collected and analyzed to better estimate the impact of these vaccines on lactation outcomes,” the team advises.
* Important message
medRxiv publish preliminary scientific reports that are not peer-reviewed and, therefore, should not be seen as final, guiding health-related clinical practice / behavior, or be treated as information established.