A new Penn Medicine study puts researchers within closer reach of vaccines that can protect infants against infections by overcoming a mother’s antibodies, which are known to shut down immune defenses initiated by conventional vaccines. That hurdle largely explains why vaccinations for infectious diseases like influenza and measles are not given until 6 to 12 months of age. Findings from the preclinical study were published online in Science Translational Medicine.

The research team, led by Scott E. Hensley, an associate professor of microbiology, and Drew Weissman, a professor of infectious diseases in the Perelman School of Medicine, found that a specialized modified-RNA (mRNA) influenza vaccine developed at Penn successfully protected young mice against the infection in the presence of maternal antibodies. The study suggests this protection occurred because the vaccine programs cells to constantly churn out new antigens for a prolonged period of time, rather than delivering a one-time shot of a viral protein.

“Around the world, every year, many young infants become infected and often die from infections because of a lack of effective vaccines to protect them earlier in life,” Weissman says. “mRNA-based vaccines could potentially help prevent that. What’s more, it would not only be effective against influenza but also other pathogens, as the vaccine’s platform is easily adaptable to different antigens.”