Assessing classroom and laboratory spread of COVID-19 in a university after elimination of physical distancing

PLOS ONE RESEARCH ARTICLE Assessing classroom and laboratory spread of COVID-19 in a university after elimination of physical distancing Terri Rebmann ID1,2*, Travis M. Loux3, Ashley Gomel2, Kaeli A. Lugo2, Firas Bafageeh3, Haley Elkins4, Lauren D. Arnold3 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 1 Institute for Biosecurity, College for Public Health and Social Justice, Saint Louis University, St Louis, Missouri, United States of America, 2 President’s Office, Saint Louis University, St Louis, Missouri, United States of America, 3 Department of Epidemiology and Biostatistics, College for Public Health and Social Justice, Saint Louis University, St Louis, Missouri, United States of America, 4 Saint Louis County Department of Public Health, St Louis, Missouri, United States of America * Abstract OPEN ACCESS Citation: Rebmann T, Loux TM, Gomel A, Lugo KA, Bafageeh F, Elkins H, et al. (2023) Assessing classroom and laboratory spread of COVID-19 in a university after elimination of physical distancing. PLoS ONE 18(3): e0283050. https://doi.org/ 10.1371/journal.pone.0283050 Editor: Mayar Al Mohajer, Baylor College of Medicine, UNITED STATES Received: November 3, 2022 Accepted: February 28, 2023 Published: March 16, 2023 Copyright: © 2023 Rebmann et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: We cannot publicly share our full data set due to IRB restrictions (the data is considered sensitive since it involves employee and student COVID-19 infection and exposure data). We have arranged to have a nonauthor institutional contact for data access. His name is Dr Min Qian, who can be reached at: . Funding: The authors received no specific funding for this work. The objective of this study was to assess COVID-19 classroom transmission in the university setting when physical distancing was eliminated. Data was collected in fall 2021 at a private university. Universal masking, robust contact tracing, vaccination requirement, and enforced testing were in place. Exposures were classified as classroom versus non-classroom. ANOVA and chi-squared tests were used to identify significant relationships between predictors and COVID-19 test result. Logistic regression was conducted to investigate the relationship between exposure type and test result. A total of 162 student cases were identified with 1,658 associated close contacts. One-third of contacts (31.1%, n = 516) only had a non-classroom exposure, 63.8% (n = 1,057) only had a classroom exposure, and 5.1% (n = 85) had both. Close contacts were significantly more likely to test positive if they had a non-classroom exposure (60 of 601; 10.0%) compared to a classroom exposure (1 of 1057; 0.1%) (OR 58.8, CI 18.5–333.3, p < 0.001). Removing physical distancing in classrooms that had universal masking did not result in high rates of COVID-19 transmission. This has policy implications because eliminating physical distancing does not greatly increase transmission risk when universal masking is in place. Background The COVID-19 pandemic greatly changed the way educational institutions functioned. Many institutions of higher education (IHEs) elected to only offer online education during the 2020/ 2021 academic year. Those that remained open for in-person instruction had to implement extensive mitigation strategies, such as universal masking, physical distancing in classrooms and non-classroom/social spaces, reducing density on campus, diagnostic and asymptomatic surveillance testing, daily health screening for employees and students, isolation, quarantine, and contact tracing [1, 2]. These interventions were expensive and not sustainable for most PLOS ONE | https://doi.org/10.1371/journal.pone.0283050 March 16, 2023 1/9 PLOS ONE Competing interests: The authors have declared that no competing interests exist. Elimination of physical distancing IHEs [2]. Furthermore, after COVID-19 vaccine became widely available to IHE students and employees in mid-spring 2021, there appeared to be less need for such extensive public health safeguards. Physical distancing was one of the most difficult COVID-19 mitigation strategies to implement for IHEs, because maintaining six feet of physical distance between students and faculty often reduced classroom capacity to 50% or less. Many IHEs were required to use event or meeting space as classroom space in order to accommodate physical distancing. This was not a sustainable solution, but the risk of eliminating physical distancing in classrooms was unknown. A study conducted in a K-12 school setting found that COVID-19 transmission can occur in schools when physical distancing and universal masking compliance are lacking [3], but there was not sufficient data on the impact of masking versus physical distancing. In planning for the 2021–2022 academic year, the American College Health Association issued guidelines for reopening institutions of higher education in fall 2021 [4] that stated the need for classroom physical distancing was dependent on whether a vaccine requirement policy was implemented, which variant(s) was circulating, and community transmission rates. These ACHA guidelines were consistent with CDC guidance that indicated that some COVID-19 safeguards, including physical distancing, could be relaxed at IHEs that had high vaccine uptake in a setting of low community infection transmission rates [5]. This meant that many IHE classrooms could return to pre-pandemic capacity, with students sitting close to one another once again. However, the impact of eliminating physical distancing in IHE classrooms, even with a COVID-19 vaccine requirement policy and universal masking, was unknown. The purpose of this study was to assess classroom spread of COVID-19 at an IHE with a COVID-19 vaccine policy that required students and employees to be up-to-date with the COVID-19 vaccination series at that time, consisting of completion of the primary vaccination series. Also in place was a universal masking requirement, but classroom physical distancing was eliminated for the fall 2021 semester. It was hypothesized that close contacts who only had masked exposure to an infected individual in a classroom would have lower infection rates compared to close contacts who had exposure(s) to an infected individual in social settings outside of the classroom. Methods Data was collected for the entire fall 2021 semester (August 18—December 21, 2021) at Saint Louis University (SLU), a medium-sized Midwestern private IHE, with approximately 12,000 students and 6,000 employees who lived and/or worked on campus that semester. SLU required all employees and students to receive the COVID-19 primary vaccination series before the start of the fall 2021 semester unless they had an appr (...truncated)