Calculating the risks of COVID-19 introductions into schools

Houston Independent School District (HISD) is the eighth largest school district in the United States and comprises 284 schools, nearly 215,000 students, and 40,000 staff members. The feasibility and risks of restarting in-person activities on school campuses will partially depend on the changing prevalence of SARS-CoV-2 in the Houston Metropolitan Area. As community prevalence decreases, the chance that students or staff arrive at school infected should also decrease. In this report, we provide simple calculations to help school leadership, students, families and teachers gauge risks in the weeks ahead.