COVID-19 Cases and Transmission in 17 K–12 Schools — Wood County, Wisconsin, August 31–November 29, 2020

Abstract

On January 26, 2021, this report was posted as an MMWR Early Release on the MMWR website (https://www.cdc.gov/mmwr). The coronavirus disease 2019 (COVID-19) pandemic has disrupted in-person learning in the United States, with approximately one half of all students receiving online-only instruction since March 2020.* Discontinuation of in-person schooling can result in many hardships (1) and disproportionately affects families of lower socioeconomic status (2). Current evidence suggests that transmission of SARS-CoV-2, the virus that causes COVID-19, in kindergarten through grade 12 (K-12) schools might not significantly contribute to COVID-19 spread nationwide (3). During August 31-November 29, 2020, COVID-19 cases, spread, and compliance with mask use were investigated among 4,876 students and 654 staff members who participated in in-person learning in 17 K-12 schools in rural Wisconsin. School-attributable COVID-19 case rates were compared with rates in the surrounding community. School administration and public health officials provided information on COVID-19 cases within schools. During the study period, widespread community transmission was observed, with 7%-40% of COVID-19 tests having positive results. Masking was required for all students and staff members at all schools, and rate of reported student mask-wearing was high (>92%). COVID-19 case rates among students and staff members were lower (191 cases among 5,530 persons, or 3,453 cases per 100,000) than were those in the county overall (5,466 per 100,000). Among the 191 cases identified in students and staff members, one in 20 cases among students was linked to in-school transmission; no infections among staff members were found to have been acquired at school. These findings suggest that, with proper mitigation strategies, K-12 schools might be capable of opening for in-person learning with minimal in-school transmission of SARS-CoV-2. Among 18 selected schools in Wood County, Wisconsin, 17 agreed to participate in this study of COVID-19 in schools and compliance with mask use. One school opted not to participate based on teacher preference. Surveillance was initiated by a small group of physician and medical student researchers. Participating schools were from three public school districts, one private school district, and one independent private school. Eight schools were elementary (grades K-6) with 1,529 students attending in-person, and nine were * Accessed January 13, 2021. https://cai.burbio.com/school-opening-tracker/

Effectiveness of Non-Pharmaceutical Interventions on Child and Staff COVID-19 Cases in US Summer Camps

“…Our findings are consistent with evidence showing lower incidence rates in children overall [6] and within congregate settings [7], reduced risks of SARS-CoV-2 infection with the use of facial coverings and physical distancing [2,8,9,10] and with anecdotal evidence of SARS-CoV-2 outbreaks in camps where camper and often staff face coverings was not universal [3,4,11]. For example, in a study of COVID-19 cases and transmission in 17…”

“…Wisconsin schools, authors reported low transmission rates in schools that required student masking and cohorting [10]. Correspondingly, In a study of almost 2 million confirmed COVID-19 cases from 190 countries [12], for example, the individual and combined effectiveness of mandatory public face coverings, quarantine, social distancing, and traffic restrictions on the COVID-19 effective reproduction number (R t ) was examined.…”

Reported COVID-19 Incidence in Wisconsin High School Athletes During Fall 2020

“…This is consistent with prior reports that schools have not been significant contributors to the spread of COVID-19. 20 However, 90% of our respondent schools reported in-person instruction, making it difficult to fully evaluate the role of in-person school instruction in COVID-19 incidence among high school athletes. Nonetheless, we included school instruction type within our adjusted models in order to account for this as a potential confounder.…”

Data and Policy to Guide Opening Schools Safely to Limit the Spread of SARS-CoV-2 Infection

“…Similarly, in a report released by CDC on January 26, 2021, with data from 17 K-12 schools in rural Wisconsin with high mask adherence (4876 students and 654 staff), COVID-19 incidence was lower in schools than in the community. 7 During 13 weeks in the fall of 2020, there were 191 COVID-19 cases in staff and students, with only 7 of these cases determined to result from inschool transmission. A European Centre for Disease Prevention and Control report from December 2020 that included findings from 17 country-level surveys found that 12 countries reported from 1 (Latvia) to 400 (Spain) school-based clusters of 2 or more epidemiologically linked SARS-CoV-2 infections, but that overall cluster sizes were small (most <10 cases) and could often not be definitively linked to in-school vs community-based transmission.…”