Low SARS-CoV-2 Transmission in Elementary Schools - Salt Lake County, Utah, December 3, 2020-January 31, 2021

MMWR Morb Mortal Wkly Rep. 2021 Mar 26;70(12):442-448. doi: 10.15585/mmwr.mm7012e3.

Abstract

School closures affected more than 55 million students across the United States when implemented as a strategy to prevent the transmission of SARS-CoV-2, the virus that causes COVID-19 (1). Reopening schools requires balancing the risks for SARS-CoV-2 infection to students and staff members against the benefits of in-person learning (2). During December 3, 2020-January 31, 2021, CDC investigated SARS-CoV-2 transmission in 20 elementary schools (kindergarten through grade 6) that had reopened in Salt Lake County, Utah. The 7-day cumulative number of new COVID-19 cases in Salt Lake County during this time ranged from 290 to 670 cases per 100,000 persons. Susceptible§ school contacts (students and staff members exposed to SARS-CoV-2 in school) of 51 index patients** (40 students and 11 staff members) were offered SARS-CoV-2 reverse transcription-polymerase chain reaction (RT-PCR) testing. Among 1,041 susceptible school contacts, 735 (70.6%) were tested, and five of 12 cases identified were classified as school-associated; the secondary attack rate among tested susceptible school contacts was 0.7%. Mask use among students was high (86%), and the median distance between students' seats in classrooms was 3 ft. Despite high community incidence and an inability to maintain ≥6 ft of distance between students at all times, SARS-CoV-2 transmission was low in these elementary schools. The results from this investigation add to the increasing evidence that in-person learning can be achieved with minimal SARS-CoV-2 transmission risk when multiple measures to prevent transmission are implemented (3,4).

MeSH terms

  • Adult
  • COVID-19 / epidemiology*
  • COVID-19 / prevention & control
  • COVID-19 / transmission*
  • COVID-19 Nucleic Acid Testing
  • Child
  • Child, Preschool
  • Contact Tracing
  • Female
  • Humans
  • Male
  • Masks / statistics & numerical data
  • Middle Aged
  • Physical Distancing
  • SARS-CoV-2 / isolation & purification*
  • Schools / organization & administration
  • Schools / statistics & numerical data*
  • Utah / epidemiology