Improving Mask Use and Ventilation to Reduce the Incidence of COVID-19 in Elementary Schools - Georgia, November 16 to December 11, 2020
Schools in kindergarten through fifth grade educate and address the physical, social, and emotional needs of students. Preventing SARS-CoV-2 transmission in schools is essential for safe face-to-face learning.
The incidence of COVID-19 was 37% lower in schools where teachers and staff were required to use masks and 39% lower in schools with improved ventilation. Ventilation strategies associated with lower incidence included dilution alone (35% lower incidence) or in combination with filtration (48% lower incidence).
Improving mask requirements and ventilation for teachers and staff is an important strategy in addition to teacher and staff vaccination that elementary schools can implement as part of a multi-factorial approach to providing safer face-to-face learning environments.
Gettings J, Czarnik M, Morris E, etal. Improving mask use and ventilation to reduce the incidence of COVID-19 in elementary schools-Georgia, November 16-December 11, 2020.MMWRMorbMortal WklyRep. ePub: May 21, 2021. doi: http: //dx.doi.org/10.15585 /mmwr.mm7021e1 external icon.
DESCRIPTION
This study was conducted to investigate the incidence and methods of control of infection in Georgia between November 16 and December 11, 2020, when many schools reopened and infection control measures in schools, such as the use of masks and improved ventilation, were required.
The incidence rate before COVID-19 vaccination was found to be 37% lower in schools where everyone involved in the school used masks, and 39% lower in schools where masks and classroom ventilation were practiced. Therefore, the results state that infection control measures need to be multifaceted and explain that these measures are a necessity until vaccination is available.
Schools with improved ventilation using only dilution methods had a 35% lower incidence of COVID-19, but schools with a combination of dilution and filtration had a 48% lower incidence. This is done by leaving doors and windows open and using fans to increase airflow through open windows, making ventilation a simple and cost effective method. In addition, installation of HEPA filters and UVGIs should be considered in administrative offices and rooms where nurses are stationed, but in practice they report that they are confident that ventilation in classrooms has improved.
There are, however, four limitations to the findings of this study. First, many of the COVID-19 cases were self-reported by staff and parents or guardians, and the prevention strategies reported by administrators and nurses may not reflect daily activities or be representative of all school classrooms. Second, we have limited power to detect the low incidence of potentially effective but less frequently implemented strategies, such as air filtration and purification systems. Third, the low response rate (11.6%) indicates that some participating schools lack information on ventilation improvements. However, the incidence per 500 students participated (3.08 cases) and non-participated (2.90 cases) schools, suggesting that systematic bias may be low. Finally, the data from this cross-sectional study cannot be used to infer causality.
We should refrain from making statements such as it does not occur because we are taking all possible measures, and due to the difficulty in tracking what is the source of the outbreak, the results obtained may be the only way to judge whether the measures are good or bad.
Let's take a more calm approach to infection control.
