Modifications to student quarantine policies in K-12 schools implementing multiple COVID-19 prevention strategies restores in-person education without increasing SARS-CoV-2 transmission risk, January-March 2021.

OBJECTIVE: To determine whether modified K-12 student quarantine policies that allow some students to continue in-person education during their quarantine period increase schoolwide SARS-CoV-2 transmission risk following the increase in cases in winter 2020-2021. METHODS: We conducted a prospective cohort study of COVID-19 cases and close contacts among students and staff (n = 65,621) in 103 Missouri public schools. Participants were offered free, saliva-based RT-PCR testing. The projected number of school-based transmission events among untested close contacts was extrapolated from the percentage of events detected among tested asymptomatic close contacts and summed with the number of detected events for a projected total. An adjusted Cox regression model compared hazard rates of school-based SARS-CoV-2 infections between schools with a modified versus standard quarantine policy. RESULTS: From January-March 2021, a projected 23 (1%) school-based transmission events occurred among 1,636 school close contacts. There was no difference in the adjusted hazard rates of school-based SARS-CoV-2 infections between schools with a modified versus standard quarantine policy (hazard ratio = 1.00; 95% confidence interval: 0.97-1.03). DISCUSSION: School-based SARS-CoV-2 transmission was rare in 103 K-12 schools implementing multiple COVID-19 prevention strategies. Modified student quarantine policies were not associated with increased school incidence of COVID-19. Modifications to student quarantine policies may be a useful strategy for K-12 schools to safely reduce disruptions to in-person education during times of increased COVID-19 community incidence.

SARS-CoV-2 active infection prevalence and seroprevalence in the adult population of St. Louis County.

BACKGROUND: The true prevalence of COVID-19 is difficult to estimate due to the absence of random population-based testing. To estimate current and past COVID-19 infection prevalence in a large urban area, we conducted a population-based survey in St. Louis County, Missouri. METHODS: The population-based survey of active infection (PCR) and seroprevalence (IgG antibodies) of adults (≥18 years) was conducted through random-digit dialing and targeted sampling of St. Louis County residents with oversampling of Black residents. Infection prevalence of residents was estimated using design-based and raking weighting. RESULTS: Between August 17 and October 24, 2020, 1245 residents completed a survey and underwent PCR testing; 1073 residents completed a survey and underwent PCR and IgG testing or self-reported results. Weighted prevalence estimates of residents with active infection were 1.9% (95% CI, 0.4%-3.3%) and 5.6% were ever infected (95% CI, 3.3%-8.0%). Overall infection hospitalization and fatality ratios were 4.9% and 1.4%, respectively. CONCLUSIONS: Through October 2020, the percentage of residents that had ever been infected was relatively low. A markedly higher percentage of Black and other minorities compared to White residents were infected with COVID-19. The St. Louis region remained highly vulnerable to widespread infection in late 2020.

All Hands on Deck: Local Public Health Agencies Leveraging the Incident Command System During Crises.

The COVID-19 pandemic has stretched limited public health resources beyond measures, particularly at the local level. What started as an interesting report of pneumonia of unknown etiology in late December 2019 in Wuhan, China, bloomed into an international crisis by mid-January 2020. However, it was not until late January, when the first case was reported in the United States, that a new reality took shape for US public health agencies. After all, severe acute respiratory syndrome never made it to this country, and the only 2 cases of Middle East respiratory syndrome here were imported and never spread. Local public health agencies are notoriously short-staffed and underfunded. Therefore, when a crisis looms, personnel from a multitude of areas within the agencies are called upon to help out. Under its innovative and forward-thinking leadership, the St. Louis County Department of Health internally implemented the Incident Command System, a component of the National Incident Management System. While reassignment of individuals to new responsibilities under a new and temporary reporting structure did not always go perfectly, Incident Command System kept its promise to be adaptable to a fast-evolving situation, to clearly outline needed areas of responsibility, and to provide scaffolding that kept the Department of Health functional in chaotic times. It was able to be implemented quickly within hours of the first confirmed COVID-19 case in St. Louis County and enhanced the quality and timeliness of the public health response. This experience is being shared to provide a model of how organizations with limited personnel can use the Incident Command System to reorganize and meet unexpected challenges with increased success.

Pilot Investigation of SARS-CoV-2 Secondary Transmission in Kindergarten Through Grade 12 Schools Implementing Mitigation Strategies - St. Louis County and City of Springfield, Missouri, December 2020.

Many kindergarten through grade 12 (K-12) schools offering in-person learning have adopted strategies to limit the spread of SARS-CoV-2, the virus that causes COVID-19 (1). These measures include mandating use of face masks, physical distancing in classrooms, increasing ventilation with outdoor air, identification of close contacts,* and following CDC isolation and quarantine guidance† (2). A 2-week pilot investigation was conducted to investigate occurrences of SARS-CoV-2 secondary transmission in K-12 schools in the city of Springfield, Missouri, and in St. Louis County, Missouri, during December 7-18, 2020. Schools in both locations implemented COVID-19 mitigation strategies; however, Springfield implemented a modified quarantine policy permitting student close contacts aged ≤18 years who had school-associated contact with a person with COVID-19 and met masking requirements during their exposure to continue in-person learning.§ Participating students, teachers, and staff members with COVID-19 (37) from 22 schools and their school-based close contacts (contacts) (156) were interviewed, and contacts were offered SARS-CoV-2 testing. Among 102 school-based contacts who received testing, two (2%) had positive test results indicating probable school-based SARS-CoV-2 secondary transmission. Both contacts were in Springfield and did not meet criteria to participate in the modified quarantine. In Springfield, 42 student contacts were permitted to continue in-person learning under the modified quarantine; among the 30 who were interviewed, 21 were tested, and none received a positive test result. Despite high community transmission, SARS-CoV-2 transmission in schools implementing COVID-19 mitigation strategies was lower than that in the community. Until additional data are available, K-12 schools should continue implementing CDC-recommended mitigation measures (2) and follow CDC isolation and quarantine guidance to minimize secondary transmission in schools offering in-person learning.