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Posted Apr 4, 2020, 9:10 PM
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Registered User
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Join Date: Dec 2016
Location: San Francisco
Posts: 24,176
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Quote:
Rapid Sentinel Surveillance for COVID-19 — Santa Clara County, California, March 2020
Early Release / April 3, 2020 / 69
Marissa L. Zwald, PhD1; Wen Lin, MD, PhD2; Gail L. Sondermeyer Cooksey, MPH3; Charles Weiss, MD4; Angela Suarez, MD5; Marc Fischer, MD1; Brandon J. Bonin, MS2; Seema Jain, MD3; Gayle E. Langley, MD1; Benjamin J. Park, MD1; Danielle Moulia, MPH1; Rory Benedict4; Nang Nguyen, PhD5; George S. Han, MD2 (View author affiliations)
Summary
On February 27, 2020, Santa Clara County, California, identified its first case of coronavirus disease 2019 (COVID-19) associated with probable community transmission.
During March 5–14, among patients with respiratory symptoms evaluated at one of four Santa Clara County urgent care centers serving as sentinel surveillance sites, 23% had positive test results for influenza. Among a subset of patients with negative test results for influenza, 11% had positive test results for COVID-19.
COVID-19 cases identified through this sentinel surveillance system helped confirm community transmission in the county. Local health departments can use sentinel surveillance to understand the level of community transmission of COVID-19 and to better guide the selection and implementation of community mitigation measures . . . .
Discussion
Identification of cases from this sentinel surveillance system helped confirm community transmission of SARS-CoV-2 in Santa Clara County. Among county residents evaluated at participating urgent care centers in early March with respiratory illness and no known exposure to SARS-CoV-2, approximately one quarter had positive test results for influenza, but 11% of patients with negative test results for influenza had positive test results for COVID-19. If it is assumed there were no influenza and SARS-CoV-2 coinfections and that persons with negative test results for influenza and not tested for SARS-CoV-2 were similar to those who were tested, then an estimated 8% (19 of 226) of persons seen at participating urgent care centers with respiratory symptoms had COVID-19. This is similar to the 5% SARS-CoV-2 infection rate identified among patients evaluated for mild influenza-like illness at one Los Angeles medical center during a similar time frame.
The findings in this report are subject to at least two limitations. First, SARS-CoV-2 testing was performed on a convenience sample of specimens that tested negative for influenza. Second, the findings are based on a small number of patients evaluated for respiratory illness at four participating sentinel sites and might not be representative of the broader community. However, as a result of these data and an increasing number of cases with no known source of transmission in Santa Clara County, the county initiated a series of community mitigation strategies to slow the spread of SARS-CoV-2. On March 9, the county issued recommendations to cancel gatherings of ≥1,000 people and to take action to protect vulnerable populations (e.g., older adults).* On March 16, Santa Clara County and five adjacent counties joined to order all residents to shelter in place and all schools, businesses, and government agencies to cease nonessential operations. Santa Clara County also posted updated community mitigation guidance and recommendations for populations at high risk, long-term care facilities, and hospitals.
Early implementation of community intervention is likely essential to maximize its effectiveness in slowing the spread of SARS-CoV-2. Local public health departments can use sentinel surveillance to assess the level of community transmission of COVID-19 and to better guide the selection and implementation of community mitigation measures, including the scale, timing, duration, and settings in which to focus these strategies. Sentinel surveillance in outpatient settings and emergency departments, implemented together with hospital-based surveillance, mortality surveillance, and serologic surveys, can provide a robust, multifaceted approach to monitor the epidemiology of COVID-19.
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https://www.cdc.gov/mmwr/volumes/69/...cid=mm6914e3_w
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