During the 2020-2021 school year, many schools adopted remote learning or a part-time in-person learning ("hybrid") approach to reduce the risk of in-school transmission of COVID-19. The purpose of this work is to describe case rates of COVID-19 in schools practicing different learning modalities on rates of COVID-19 to support risk-benefit decisions in the context of respiratory disease outbreaks. We conducted a person-time-at-risk analysis of rates of COVID-19, as well as testing and test positivity rates among Colorado students. Schools practicing remote learning had a lower adjusted rate of COVID-19 cases compared to either hybrid or in-person learning modalities. Students attending a school with remote learning had fewer reported tests, and test positivity was higher for remote learning. Our analysis found that both case rate and test positivity were similar in hybrid and in-person learning modalities, indicating that hybrid learning modalities may not reduce the risk of respiratory disease transmission.