The World Health Organization (WHO) has maintained it does not recommend that women vaccinated against COVID-19 discontinue breastfeeding. Though the international health agency recommends the coronavirus vaccine in adults, including lactating women, it has been previously reported that mRNA could be transferred to children via breast milk.
No detectable levels of messenger RNA (mRNA) from vaccines against COVID-19 were found in human milk, according to a new study that analyzed the post-vaccination breast milk samples of seven women earlier this year.
Findings of the small study, approved by the UCSF institutional review board and published earlier this month in JAMA Pediatrics, comes amid concerns that the Pfizer-BioNTech and Moderna vaccines – both of which contain mRNA – could have a negative impact on mothers and their breastfeeding children.
“The results strengthen current recommendations that the mRNA vaccines are safe in lactation, and that lactating individuals who receive the COVID vaccine should not stop breastfeeding,” said Dr. Stephanie Gaw, a corresponding author and assistant professor of Maternal-Fetal Medicine at UCSF.
Storage conditions of the self-collected milk samples could have impacted mRNA stability.
Like the authors of the study, the WHO, as well as the Academy of Breastfeeding Medicine, have declared women who received mRNA-based COVID-19 vaccines should not cease breastfeeding their young children.
“Vaccine effectiveness is expected to be similar in lactating women as in other adults. WHO recommends the use of the vaccine in lactating women as in other adults,” the WHO said in an April release, noting that the benefits of COVID-19 vaccines in pregnant women “outweigh the potential risks.”