Abstract
Objectives: Widespread global transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing coronavirus disease 2019 (COVID-19), continues. Many questions remain about asymptomatic or atypical infections and transmission dynamics. We used comprehensive contact tracing of the first 2 confirmed patients in Illinois with COVID-19 and serologic SARS-CoV-2 antibody testing to determine whether contacts had evidence of undetected COVID-19. Methods: Contacts were eligible for serologic follow-up if previously tested for COVID-19 during an initial investigation or had greater-risk exposures. Contacts completed a standardized questionnaire during the initial investigation. We classified exposure risk as high, medium, or low based on interactions with 2 index patients and use of personal protective equipment (PPE). Serologic testing used a SARS-CoV-2 spike enzyme-linked immunosorbent assay on serum specimens collected from participants approximately 6 weeks after initial exposure to either index patient. The 2 index patients provided serum specimens throughout their illness. We collected data on demographic, exposure, and epidemiologic characteristics. Results: Of 347 contacts, 110 were eligible for serologic follow-up; 59 (17% of all contacts) enrolled. Of these, 53 (90%) were health care personnel and 6 (10%) were community contacts. Seventeen (29%) reported high-risk exposures, 15 (25%) medium-risk, and 27 (46%) low-risk. No participant had evidence of SARS-CoV-2 antibodies. The 2 index patients had antibodies detected at dilutions >1:6400 within 4 weeks after symptom onset. Conclusions: In serologic follow-up of the first 2 known patients in Illinois with COVID-19, we found no secondary transmission among tested contacts. Lack of seroconversion among these contacts adds to our understanding of conditions (ie, use of PPE) under which SARS-CoV-2 infections might not result in transmission and demonstrates that SARS-CoV-2 antibody testing is a useful tool to verify epidemiologic findings.
Original language | English (US) |
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Pages (from-to) | 88-96 |
Number of pages | 9 |
Journal | Public health reports |
Volume | 136 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2021 |
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Centers for Disease Control and Prevention. The authors thank all participants for their time and interest in this investigation; Barney Graham, MD, PhD, and Kizzmekia Corbett, PhD, for the SARS-CoV-2 expression plasmid for assay use; Allison Arwady, MD, Erin Conners, PhD, and Michael Hernandez, MD, for logistical support; and Stefany Moye, BS, for laboratory support. We also acknowledge numerous associates and staff members at AMITA Health St. Alexius Medical Center, Cook County Department of Public Health, Chicago Department of Public Health, DuPage County Health Department, Illinois Department of Public Health, and members of the Emergency Operations Center and Division of Viral Diseases in the National Center for Immunization and Respiratory Diseases at the Centers for Disease Control and Prevention. The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Centers for Disease Control and Prevention.
Keywords
- COVID-19
- SARS-CoV-2
- antibodies
- epidemiology
- serology
ASJC Scopus subject areas
- Public Health, Environmental and Occupational Health