Although employees showing COVID-19 symptoms are currently discouraged from going to work, significant workplace COVID-19 outbreaks were recently reported. Virus spread by asymptomatic SARS-CoV-2 infected individuals has been reported to be a significant cause of contamination clusters. Yet, other than PCR testing every employee each day using an invasive nasal or nasopharyngeal swab, few options exist to detect asymptomatic virus spreaders who can contaminate other employees or visitors.   Foll...