Related Experiment Video
Updated: Oct 13, 2025
Large-Scale SARS-CoV-2 Testing Utilizing Saliva and Transposition Sample Pooling
Published on: June 23, 2022
Testing for SARS-CoV-2 in Symptomatic Vaccinated and Unvaccinated Health Care Workers During the Delta Variant Surge
Anthony Lopez1, Robert Kosnik, Paul D Blanc
1Division of Occupational and Environmental Medicine, Department of Medicine, San Francisco Veterans Affairs Health Care System (Mr Lopez, Dr Blanc, Dr Guntur); Division of Occupational Medicine, Department of Medicine, University of California San Francisco (Dr Kosnik, Dr Blanc, Dr Guntur); and Office of Population Health, University of California San Francisco Medical Center (Dr Taylor), University of California San Francisco, San Francisco, California.
Background:
Infection with SARS- CoV- 2 in health care workers (HCWs) challenges employee health services.
Methods:
We analyzed telephone Coronavirus Disease 2019 (COVID-19) hotline data over 8 weeks in 2021 during SARS- CoV- 2 Delta variant surge. We calculated COVID-19 case rates among persons-under-investigation (PUIs) for illness at two health care centers (HCs).
Results:
There were 41 COVID-19 cases among the 285 PUIs (14.4%) at the study HC and 549 (16.9%) of 3244 at the comparison HC. At the study HC, 11.7% of vaccinated PUIs versus 36.6% of unvaccinated PUIs were COVID-19 positive. The COVID-19 positivity rates among vaccinated and unvaccinated PUIs at the comparison HC were 16.1% and 33.3%, respectively.
Discussion:
In the SARS-CoV-2 Delta variant surge, COVID-19 test positivity rates among unvaccinated symptomatic HCWs are dramatically elevated. Aggressive testing of HCW PUIs is particularly critical during periods of disease upsurge.
More Related Videos
Related Concept Videos
01:29Contingency Table
01:13Controls in Experiments
01:17Transmission-based Precautions I: Contact, Enteric, and Droplets
Contact Precautions:
Contact precautions are the measures taken to prevent the transmission of infectious agents, especially epidemiologically important microorganisms such as MRSA or influenza, primarily transmitted through direct or indirect contact with an...