Hypothesis: School reopening had a significant impact on COVID-19 infection rates across USA states. Eight states with fully reopened public schools were studied. States who did not previously have stay-at-home orders for a minimum of 30days were excluded from the study so that increases in infection rates would be solely due to the economies of reopening. This study used event study methodology with a 30-day estimation window. This allowed us to determine if increases in COVID-19 infection rates were significant following schools reopening. Eight states were analyzed, and seven of the states had positive and significant COVID-19 infection increases. The other state's increase was negative and significant. This study found that reopening of schools had an initial 5-day increase in COVID-19 infections in seven of eight states whose data were examined. With schools being re-opened nationwide in Fall 2021, this indicates that with the Delta variant there is an expected significant increase in infections.