(Ames, IA) -- Iowa State University is looking at the effectiveness of the CDC's COVID-19 vaccine rollout in Iowa. ISU researchers ran 17 million strategic models to analyze the ways the CDC could have rolled out the vaccines. They found the CDC's strategy was close to optimal, but could have prioritized different types of pre-existing conditions that were more critical than others. Iowa State researchers are now looking into how the pandemic may further develop if people do or don't receive booster shots.