Vaccines have been saving lives for over 200 years, but recent decisions by the current administration have put millions at risk for known diseases as well as possible future pandemics. In this presentation, IU Emerita Professor of Biology, Patricia Foster, will briefly review what vaccines are, how they protect against infections, and how their efficacy and safety are determined. Then she will delve into the science of mRNA vaccines, how they were developed, how effective they were against the COVID pandemic, and why they are our best defense against upcoming pandemics.