The breast milk of lactating mothers vaccinated against Covid-19 contains a significant supply of antibodies that may help protect nursing infants from the illness, according to new research from the University of Florida.
The study showed a robust antibody response in blood and breast milk after the second dose -- about a hundred-fold increase compared with levels before vaccination -- higher than those observed after natural infection with the virus.
The findings, published in the journal Breastfeeding Medicine, strongly suggest that vaccines can help protect both mother and the baby, another compelling reason for pregnant or lactating women to get vaccinated.
"Our findings show that vaccination results in a significant increase in antibodies against SARS-CoV-2 -- the virus that causes Covid-19 -- in breast milk, suggesting that vaccinated mothers can pass on this immunity to their babies, something we are working to confirm in our ongoing research," said Joseph Larkin III, Associate Professor in the department of microbiology and cell science at University of Florida, US.
When babies are born, their immune systems are underdeveloped, making it hard for them to fight infections on their own. They are also often too young to respond adequately to certain types of vaccines. During this vulnerable period, breast milk allows nursing mothers to provide infants with "passive immunity".
"Think of breast milk as a toolbox full of all the different tools that help prepare the infant for life. Vaccination adds another tool to the toolbox, one that has the potential to be especially good at preventing Covid-19 illness," said Josef Neu, Professor at the varsity's College of Medicine.
The study was conducted between December 2020 and March 2021, when the Pfizer and Moderna vaccines first became available to health care workers. For the study, researchers recruited 21 lactating health care workers who had never contracted Covid-19.
The research team is continuing to explore how breast milk, containing Covid-19 antibodies gained through vaccination, protects babies who consume it.
"We would like to know if infants who consume breast milk containing these antibodies develop their own protection against Covid-19. In addition, we would also like to know more about the antibodies themselves, such as how long they are present in breast milk and how effective they are at neutralising the virus," the researchers said.