SARS-CoV-2 Incidence in K–12 School Districts with Mask-Required Versus Mask-Optional Policies — Arkansas, August–October 2021

Abstract

On March 8, 2022 this report was posted as an MMWR Early Release on the MMWR website (https://www.cdc.gov/mmwr).Masks are effective at limiting transmission of SARS-CoV-2, the virus that causes COVID-19 (1), but the impact of policies requiring masks in school settings has not been widely evaluated (2-4). During fall 2021, some school districts in Arkansas implemented policies requiring masks for students in kindergarten through grade 12 (K-12). To identify any association between mask policies and COVID-19 incidence, weekly school-associated COVID-19 incidence in school districts with full or partial mask requirements was compared with incidence in districts without mask requirements during August 23-October 16, 2021. Three analyses were performed: 1) incidence rate ratios (IRRs) were calculated comparing districts with full mask requirements (universal mask requirement for all students and staff members) or partial mask requirements (e.g., masks required in certain settings, among certain populations, or if specific criteria could not be met) with school districts with no mask requirement; 2) ratios of observed-to-expected numbers of cases, by district were calculated; and 3) incidence in districts that switched from no mask requirement to any mask requirement were compared before and after implementation of the mask policy. Mean weekly district-level attack rates were 92-359 per 100,000 persons in the community* and 137-745 per 100,000 among students and staff members; mean student and staff member vaccination coverage ranged from 13.5% to 18.6%. Multivariable adjusted IRRs, which included adjustment for vaccination coverage, indicated that districts with full mask requirements had 23% lower COVID-19 incidence among students and staff members compared with school districts with no mask requirements. Observed-to-expected ratios for full and partial mask policies were lower than ratios for districts with no mask policy but * Community attack rates were based on the weekly number of cases in the school district, minus the weekly number of cases among staff members or students during the same period. Denominators were calculated based on the population for each school district, minus the district student and staff member 2021-22 enrollment.

Covid-19 in the UK: policy on children and schools

“…Although deaths from covid-19 are rare in children (85 up to June 2022, table 2), they are more common than from many other childhood illnesses (eg, mumps, measles, varicella, rubella). 78 Furthermore, death rates for children were calculated using population denominators, ignoring the substantial changes in infection rates during the pandemic. For example, in the five months from December 2021 to mid-April 2022 about 50% of 8-11 year olds in the UK caught covid-19 compared with an estimated 40% over the previous 20 months.…”

“…The effect on children was underestimated consistently, as severe disease in children was compared with that in adults rather than against other childhood illnesses. Although deaths from covid-19 are rare in children (85 up to June 2022, table 2), they are more common than from many other childhood illnesses (eg, mumps, measles, varicella, rubella) 78. Furthermore, death rates for children were calculated using population denominators, ignoring the substantial changes in infection rates during the pandemic.…”

“…Mask use remained low in classrooms in England, with secondary school headteachers reporting only 32% of secondary school children wearing masks in classrooms in December 2021 49. In January 2022, nearly two years into the pandemic, UKHSA and DfE58 acknowledged the large body of observational evidence showing that masks were effective in reducing transmission, including in school 62707178. However, masks were reintroduced in secondary schools for just three weeks during the omicron wave (table 1).…”

Impact of Lifting School Masking Requirements on Incidence of COVID-19 among Staff and Students in Greater-Boston Area School Districts: A Difference-in-Differences Analysis

“…[38][39][40][41] A growing body of evidence supports the effectiveness of universal masking requirements in reducing SARS-CoV-2 transmission both in community and school settings. [42][43][44][45][46][47][48] During the emergence of the Delta variant prior to the start of the 2021-2022 school year, CDC issued guidance recommending "... universal indoor masking by all students, staff, teachers, and visitors to K-12 schools, regardless of vaccination status". 49 However, on February 25, 2022, CDC released updated guidance that limited masking recommendations in public indoor settings (including K-12 schools) to counties with high COVID-19 Community Levels -a CDC-defined metric largely determined by COVID-19 hospitalizations.…”

BNT162b2 induces robust cross-variant SARS-CoV-2 immunity in children

“…However, as the pandemic continued, it has become evident that children, too, can suffer from severe COVID-19 1 as well as long-term disease 2 . There has been a marked increase in SARS-CoV-2 cases in children under the age of 18 3 , potentially fueled by loosened mask mandates 4 and the widespread transmission of novel variants of concern (VOC) including B.1.1.529 (Omicron) and its sub-variants 5 . In some areas in the US with low vaccination rates and lack of herd immunity, there is a four-fold increase of hospitalizations in children compared to areas with high vaccine rates 6 .…”