SARS-CoV-2 epidemiology on a public university campus in Washington State

Weil AA, Sohlberg SL, O'Hanlon JA, Casto AM, Emanuels AW, Lo NK, Greismer EP, Magedson AM, Wilcox NC, Kim AE, Back L, Frazar CD, Pelle B, Sibley TR, Ilcisin M, Lee J, Ryke EL, Craft JC, Schwabe-Fry KM, Fay KA, Cho S, Han PD, Heidl SJ, Pfau BA, Truong M, Zhong W, Srivatsan SR, Harb KF, Gottlieb GS, Hughes JP, Nickerson DA, Lockwood CM, Starita LM, Bedford T, Shendure JA, Chu HY. 2021. medRxiv: 2021.03.15.21253227.

Abstract

Background: Testing programs have been utilized as part of SARS-CoV-2 mitigation strategies on university campuses, and it is not known which strategies successfully identify cases and contain outbreaks.

Objective: Evaluation of a testing program to control SARS-CoV-2 transmission at a large university.

Design: Prospective longitudinal study using remote contactless enrollment, daily mobile symptom and exposure tracking, and self-swab sample collection. Individuals were tested if the participant was (1) exposed to a known case, developed new symptoms, or reported high-risk behavior, (2) a member of a group experiencing an outbreak, or (3) at baseline upon enrollment.

Setting: An urban, public university during Autumn quarter of 2020.

Participants: Students, staff, and faculty.

Measurements: SARS-CoV-2 PCR testing was conducted, and viral genome sequencing was performed.

Results: We enrolled 16,476 individuals, performed 29,783 SARS-CoV-2 tests, and detected 236 infections. Greek community affiliation was the strongest risk factor for testing positive. 75.0% of positive cases reported at least one of the following: symptoms (60.8%), exposure (34.7%), or high-risk behaviors (21.5%). 88.1% of viral genomes (52/59) sequenced from Greek-affiliated students were genetically identical to at least one other genome detected, indicative of rapid SARS-CoV-2 spread within this group, compared to 37.9% (11/29) of genomes from non-Greek students and employees.

Limitations: Observational study.

Conclusion: In a setting of limited resources during a pandemic, we prioritized testing of individuals with symptoms and high-risk exposure during outbreaks. Rapid spread of SARS-CoV-2 occurred within outbreaks without evidence of further spread to the surrounding community. A testing program focused on high-risk populations may be effective as part of a comprehensive university-wide mitigation strategy to control the SARS-CoV-2 pandemic.