The breast milk of mothers who have had Covid-19 vaccines contains a significant level of antibodies that may help protect nursing babies from the virus, a small study suggests.
When babies are born, their underdeveloped immune systems make it hard for them to fight infections on their own.
They are also often too young to respond adequately to certain types of vaccines, experts say.
Joseph Larkin III, senior author of the study and an associate professor at the University of Florida, said: “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.”
Josef Neu, one of the study’s co-authors and a professor in the University of Florida’s College of Medicine’s department of paediatrics, division of neonatology, said: “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.
“The results of our study strongly suggest that vaccines can help protect both mum and baby, another compelling reason for pregnant or lactating women to get vaccinated.”
The study was conducted between December 2020 and March 2021, when the Pfizer and Moderna vaccines first became available to healthcare workers in the US.
Researchers recruited 21 lactating healthcare workers who had never contracted the virus.
They sampled the mothers’ breast milk and blood three times – before vaccination, after the first dose and after the second dose.
There was a robust antibody response in blood and breast milk after the second dose, about a hundred-fold increase compared with levels before vaccination, the study found.
The data also indicates these levels are higher than those observed after natural infection with the virus.
Researchers are continuing to look at how breast milk containing Covid-19 antibodies gained through vaccination protects babies who consume it.
But they said they were encouraged by their initial results.
The study is published in the journal Breastfeeding Medicine and was funded by the Children’s Miracle Network.