Public health

Pathology

Sociology

Disease

Population

Coronavirus disease 2019 (COVID-19)

Infectious disease (medical specialty)

Outbreak

Mathematics education

Demography

Nursing

Psychology

Virology

2019-20 coronavirus outbreak

School district

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

Medicine

Environmental health

MMWR Morbidity and Mortality Weekly Report

CDC recommends universal indoor masking by students, staff members, faculty, and visitors in kindergarten through grade 12 (K-12) schools, regardless of vaccination status, to reduce transmission of SARS-CoV-2, the virus that causes COVID-19 (1). Schools in Maricopa and Pima Counties, which account for >75% of Arizona's population (2), resumed in-person learning for the 2021-22 academic year during late July through early August 2021. In mid-July, county-wide 7-day case rates were 161 and 105 per 100,000 persons in Maricopa and Pima Counties, respectively, and 47.6% of Maricopa County residents and 59.2% of Pima County residents had received at least 1 dose of a COVID-19 vaccine. School districts in both counties implemented variable mask policies at the start of the 2021-22 academic year (Table). The association between school mask policies and school-associated COVID-19 outbreaks in K-12 public noncharter schools open for in-person learning in Maricopa and Pima Counties during July 15-August 31, 2021, was evaluated.

Association Between K–12 School Mask Policies and School-Associated COVID-19 Outbreaks — Maricopa and Pima Counties, Arizona, July–August 2021