Joseph Larkin, University of Florida – What Do Babies’ Dirty Diapers Tell Us About COVID-19 Vaccination

Mothers may be protecting their babies against COVID-19 by passing along antibodies.

Joseph Larkin, associate professor of microbiology and cell science at the University of Florida, describes the process.

Joseph Larkin III is an immunologist specializing in autoimmune diseases and novel treatments for these conditions. He is also interested in understanding how human milk affects infants’ immune systems.

What Do Babies’ Dirty Diapers Tell Us About COVID-19 Vaccination

In our study, we provide evidence that moms vaccinated against COVID-19 produce antibodies in their breast milk that could protect babies from the disease. We detected the antibodies by “sifting” through babies’ poop! 

In 2019, SARS-CoV-2, the deadly virus responsible for COVID-19, emerged and completely changed our way of life.  In 2020, two mRNA vaccines received approval for emergency use. These vaccine-induced antibodies specific to the virus in adults, but questions remained about whether vaccinated individuals could provide antibodies to infants through breast milk. We were among the first groups of researchers to show that these antibodies were present in the breast milk of vaccinated moms. 

Next, we wanted to know how long antibodies continued to appear in breast milk after vaccination, and if the antibodies were functional once inside the baby.  We found that SARS-CoV-2 antibodies remained present in the breast milk of vaccinated individuals for at least 6 months.  Mothers that were providing our research with milk also happily provided us with their infants’ poop filled diapers.  Why?  Well, if we could find antibodies at the end of the digestive tract, that meant they had gotten in the baby through feeding. In the lab, we found that the antibodies present in the breast milk and stool could likely inhibit SARS-CoV-2 virus activity. Our next steps include exploring other components of breast milk that help protect infants. To the diapers we go!