Interventions to Disrupt Coronavirus Disease Transmission at a University, Wisconsin, USA, August-October 2020

Abstract

University settings have demonstrated potential for coronavirus disease (COVID-19) outbreaks; they combine congregate living, substantial social activity, and a young population predisposed to mild illness. Using genomic and epidemiologic data, we describe a COVID-19 outbreak at the University of Wisconsin-Madison, Madison, Wisconsin, USA. During August-October 2020, a total of 3,485 students, including 856/6,162 students living in dormitories, tested positive. Case counts began rising during move-in week, August 25-31, 2020, then rose rapidly during September 1-11, 2020. The university initiated multiple prevention efforts, including quarantining 2 dormitories; a subsequent decline in cases was observed. Genomic surveillance of cases from Dane County, in which the university is located, did not find evidence of transmission from a large cluster of cases in the 2 quarantined dorms during the outbreak. Coordinated implementation of prevention measures can reduce COVID-19 spread in university settings and may limit spillover to the surrounding community.

Keywords: COVID-19; COVID-19 testing; SARS-CoV-2; United States; University of Wisconsin–Madison; Wisconsin; coronavirus disease; dormitory; respiratory infections; severe acute respiratory syndrome coronavirus 2; students; university; viruses; whole-genome sequencing; zoonoses.

Figure 1

Overall epidemic curves of coronavirus disease cases among University of Wisconsin–Madison students and staff, Dane County, Wisconsin, USA, August 1–October 31, 2020. We categorized 10 student case-patients affiliated with both a dormitory and FSL as dormitory students. Student was considered the primary affiliation, such that any student who was also a staff member was categorized as a student. FSL, fraternity and sorority life.

Figure 2

Coronavirus disease epidemic curves and percent positivity for University of Wisconsin–Madison students living in dormitories A and B versus all other dormitories, Dane County, Wisconsin, USA, August 25–October 31, 2020.

Figure 3

Phylogenetic tree of the coronavirus disease outbreak in dormitories A and B, University of Wisconsin–Madison, Dane County, Wisconsin, USA, January 2020–January 2021. A) Phylogenetic tree of all cases sequenced in Dane County, Wisconsin (light gray tips) during January 2020–January 2021 and cases sequenced in each dormitory. Pink shading indicates cluster associated with dormitories A and B. B) Expanded view of phylogenetic tree of the large cluster of cases associated with dormitories A and B during the September 2020 outbreak. C) Mutations relative to the initially identified severe acute respiratory syndrome coronavirus 2 genome in Wuhan, China (GenBank accession no. MN908947.3), during the outbreak in dormitories A and B.

Figure 4

Phylogenetic tree of severe acute respiratory syndrome coronavirus 2 specimens sequenced in Dane County, Wisconsin, USA, January 2020–January 2021, coded by age of case-patient providing specimen.