Rates of Asymptomatic COVID-19 Infection and Associated Factors in Olmsted County, Minnesota, in the Prevaccination Era.

• Type of Material: Article
• Authors: Celine M Vachon, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN.; Aaron D Norman, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN.; Kavita Prasad, Integrative Medicine, Zumbro Valley Health Center, Mayo Clinic, Rochester, MN.; Dan Jensen, Department of Health, Housing and Human Services Administration, Olmsted County Public Health, Mayo Clinic, Rochester, MN.; Gavin M Schaeferle, Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN.; Kristy L Vierling, Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN.; Meaghan Sherden, Department of Epidemiology, Surveillance and Preparedness Team, Olmsted County Public Health, Mayo Clinic, Rochester, MN.; Michelle R Majerus, Administration, Hutchinson Health, Hutchinson, MN.; Katherine A Bews, Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN.; Ethan P Heinzen, Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN.; Amy Hebl, Department of Human Resources, Olmsted County, Mayo Clinic, Rochester, MN.; Kathleen J Yost, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN.; Richard B Kennedy, Vaccine Research Group, Division of General Internal Medicine, Mayo Clinic, Rochester, MN.; Elitza S Theel, Department of Laboratory Medicine and Pathology, Division of Clinical Microbiology, Mayo Clinic, Rochester, MN.; Aditya Ghosh, Department of Internal Medicine, Northeast Georgia Medical Center, Gainesville, GA.; Meghan Fries, University of Notre Dame, South Bend, IA.; Chung-II Wi, Department of Precision Population Science Lab, Mayo Clinic, Rochester, MN.; Young J Juhn, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN.; Priya Sampathkumar, Division of Infectious Diseases, Department of Medicine, Mayo Clinic, Rochester, MN.; William G Morice, Department of Laboratory Medicine & Pathology, Mayo Clinic, Rochester, MN.; Walter A Rocca, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN.; Aaron J Tande, Division of Public Health, Infectious Diseases, and Occupational Medicine, Mayo Clinic, Rochester, MN.; James R Cerhan, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN.; Andrew H Limper, Department of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN.; Henry Ting, Emory University; Gianrico Farrugia, Division of Gastroenterology & Hepatology, Department of Medicine, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN.; Rickey E Carter, Department of Quantitative Health Sciences, Mayo Clinic, Jacksonville, FL.; Lila J Finney Rutten, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN.; Robert M Jacobson, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN.; Jennifer St Sauver, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN.
• Language: English
• Date: 2022-12
• Publisher: Elsevier Inc
• Publication Version: Final Published Version
• Copyright Statement: © 2022 The Authors
• Final Published Version (URL): http://dx.doi.org/10.1016/j.mayocpiqo.2022.10.001
• Title of Journal or Parent Work: Mayo Clin Proc Innov Qual Outcomes
• Volume: 6
• Issue: 6
• Start Page: 605
• End Page: 617
• Grant/Funding Information: This research was made possible by funding from Mayo Clinic, including Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, the COVID-19 Task Force, the Division of Epidemiology, and Department of Quantitative Sciences, and the generous support of benefactors. The sources of funding had no role in the conduct of the research and/or preparation of the article, or in the study design; collection, analysis or interpretation of the data, or in the writing of the report; or the decision to submit the article for publication. This study also used the resources of the Rochester Epidemiology Project (REP) medical records-linkage system, which is supported by the National Institute on Aging (NIA; AG 058738), by the Mayo Clinic Research Committee, and by fees paid annually by REP users. The content of this article is solely the responsibility of the authors and does not represent the official views of the National Institutes of Health (NIH) or the Mayo Clinic.
• Keywords: BMI, body mass index; OR, odds ratio; SES, socioeconomic status; HOUSES, HOUsing-based SocioEconomic Status; RT-PCR, reverse transcriptase-polymerase chain reaction; REP, Rochester Epidemiology Project; PCR, polymerase chain reaction
• Research Categories: Health Sciences, Public Health

Abstract

OBJECTIVE: To estimate rates and identify factors associated with asymptomatic COVID-19 in the population of Olmsted County during the prevaccination era. PATIENTS AND METHODS: We screened first responders (n=191) and Olmsted County employees (n=564) for antibodies to SARS-CoV-2 from November 1, 2020 to February 28, 2021 to estimate seroprevalence and asymptomatic infection. Second, we retrieved all polymerase chain reaction (PCR)-confirmed COVID-19 diagnoses in Olmsted County from March 2020 through January 2021, abstracted symptom information, estimated rates of asymptomatic infection and examined related factors. RESULTS: Twenty (10.5%; 95% CI, 6.9%-15.6%) first responders and 38 (6.7%; 95% CI, 5.0%-9.1%) county employees had positive antibodies; an additional 5 (2.6%) and 10 (1.8%) had prior positive PCR tests per self-report or medical record, but no antibodies detected. Of persons with symptom information, 4 of 20 (20%; 95% CI, 3.0%-37.0%) first responders and 10 of 39 (26%; 95% CI, 12.6%-40.0%) county employees were asymptomatic. Of 6020 positive PCR tests in Olmsted County with symptom information between March 1, 2020, and January 31, 2021, 6% (n=385; 95% CI, 5.8%-7.1%) were asymptomatic. Factors associated with asymptomatic disease included age (0-18 years [odds ratio {OR}, 2.3; 95% CI, 1.7-3.1] and >65 years [OR, 1.40; 95% CI, 1.0-2.0] compared with ages 19-44 years), body mass index (overweight [OR, 0.58; 95% CI, 0.44-0.77] or obese [OR, 0.48; 95% CI, 0.57-0.62] compared with normal or underweight) and tests after November 20, 2020 ([OR, 1.35; 95% CI, 1.13-1.71] compared with prior dates). CONCLUSION: Asymptomatic rates in Olmsted County before COVID-19 vaccine rollout ranged from 6% to 25%, and younger age, normal weight, and later tests dates were associated with asymptomatic infection.