As a neonatologist, Alison Carey, M.D., sees many premature babies in the neonatal intensive care unit (NICU) who develop lung infections. "Infections are a major cause of death for these babies," says Dr. Carey, Assistant Professor of Pediatrics and Immunology at Drexel University College of Medicine in Philadelphia.
Death and disability from flu infection is highest in infants younger than 6 months, currently an age group not eligible for flu vaccines because they cannot mount a good immune response to the existing vaccines. Premature babies are also at risk for other respiratory illnesses such as respiratory syncytial virus (RSV).
Dr. Carey decided to study neonatal influenza in order to reduce the dangers that lung infections pose to babies. With a Biomedical Research Grant from the American Lung Association, she is studying flu in neonatal mice. "In the past, scientists have used adult animals and extrapolated to infants," she says. "But we've learned over the last decade that how a baby responds to infection is very different than older children and certainly than adults. That's why it's really important to be able to study treatments with an age-appropriate model."
Dr. Carey has found that when mice are infected with the flu, they have a high rate of death. But when they are treated with lactobacillus probiotics, they have a much-improved survival rate. Probiotics, known as "good" bacteria, can be found in yogurt or dietary supplements. They have been studied as an infection fighter in older children.
"The main focus of the Lung Association grant is to figure out the way in which probiotics are protecting babies' lungs," Dr. Carey says. "There are certain receptors on cells in the lungs that recognize the flu and other viruses, and we believe they are important in detecting probiotics. We want to figure out if those receptors are part of the protective mechanism of probiotics."
If the study is successful and leads to human trials, probiotics could be given to babies in the NICU or after discharge from the hospital through an inhaler or nebulizer, she says. "Premature babies often have other treatments that go directly into the lungs. Probiotics could be added to these other treatments to fight respiratory infections," she notes. The treatment also might be useful in preventing lung damage from mechanical ventilation that many premature babies rely on to support their breathing. "That damage can cause long-lasting effects," she says.
The discoveries about the workings of probiotics that are made through this research will be critical in translating the research to humans, Dr. Carey says, adding, "We need this information to take the research to the next level."
Page last updated: February 25, 2020