What is already known about this topic? School-based strategies to improve ventilation are associated with reduced incidence of COVID-19 in schools. Substantial federal resources are available to improve ventilation in schools.

What is added by this report? Among a nationally representative sample of U.S. K–12 public schools, higher-cost and resource-intensive ventilation improvement strategies, such as using portable high-efficiency particular air (HEPA) filtration systems in classrooms were less frequently reported. Overall, rural and mid-poverty schools were the least likely to report implementing several resource-intensive ventilation strategies.

What are the implications for public health practice? Ensuring use of ventilation improvement resources might reduce Transmission of SARS-CoV-2 and other infectious Diseases in schools. Focusing support on schools least likely to have implemented resource-intensive ventilation strategies might facilitate equitable implementation.

Effective COVID-19 Prevention in kindergarten through grade 12 (K–12) schools requires multicomponent Prevention strategies in school buildings and school-based transportation, including improving ventilation (1). Improved ventilation can reduce the concentration of infectious aerosols and duration of potential exposures (2,3), is linked to lower COVID-19 incidence (4), and can offer other health-related benefits (e.g., better measures of respiratory health, such as reduced allergy symptoms) (5). Whereas ambient wind currents effectively dissipate SARS-CoV-2 (the Virus that causes COVID-19) outdoors,* ventilation systems provide protective airflow and filtration indoors (6). CDC examined reported ventilation improvement strategies among a nationally representative sample of K–12 public schools in the United States using wave 4 (February 14–March 27, 2022) data from the National School COVID-19 Prevention Study (NSCPS) (420 schools), a web-based survey administered to school-level administrators beginning in summer 2021.† The most frequently reported ventilation improvement strategies were lower-cost strategies, including relocating activities outdoors (73.6%), inspecting and validating existing heating, ventilation and air conditioning (HVAC) systems (70.5%), and opening doors (67.3%) or windows (67.2%) when safe to do so. A smaller proportion of schools reported more resource-intensive strategies such as replacing or upgrading HVAC systems (38.5%) or using high-efficiency particulate air (HEPA) filtration systems in classrooms (28.2%) or eating areas (29.8%). Rural and mid-poverty–level schools were less likely to report several resource-intensive strategies. For example, rural schools were less likely to use portable HEPA filtration systems in classrooms (15.6%) than were city (37.7%) and suburban schools (32.9%), and mid-poverty–level schools were less likely than were high-poverty–level schools to have replaced or upgraded HVAC systems (32.4% versus 48.8%). Substantial federal resources to improve ventilation in schools are available.§ Ensuring their use might reduce SARS-CoV-2 Transmission in schools. Focusing support on schools least likely to have resource-intensive ventilation strategies might facilitate equitable implementation of ventilation improvements.

Suggested citation for this article: Pampati S, Rasberry CN, McConnell L, et al. Ventilation Improvement Strategies Among K–12 Public Schools — The National School COVID-19 Prevention Study, United States, February 14–March 27, 2022. MMWR Morb Mortal Wkly Rep. ePub: 7 June 2022.

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