On Oct. 6, 2021, Washington University School of Medicine announced the start of a pediatric COVID-19 vaccine clinical trial in St. Louis. About 140 area children, ages 6 months to 11 years, received the two-shot Moderna vaccine or placebo at St. Louis Childrenﾒs Hospital as part of a clinical trial involving about 100 medical institutions in the U.S. and Canada.

The study helped determine how well kids tolerated the vaccine, and their immune response.