inclusion criteria: - a healthcare worker at high risk for covid-19 exposure (defined below): * persons primarily working in emergency departments (physicians, nurses, ancillary staff, triage personnel) * persons primarily working in intensive care units (physicians, nurses, ancillary staff, respiratory therapists) * persons performing aerosol generating procedures (i.e. anesthesiologists, nurse anesthetists (crnas) * first responders (i.e. emts, paramedics)

inclusion criteria: - a healthcare worker at high risk for covid-19 exposure (defined below): * persons primarily working in emergency departments (physicians, nurses, ancillary staff, triage personnel) * persons primarily working in intensive care units (physicians, nurses, ancillary staff, respiratory therapists) * persons performing aerosol generating procedures (i.e. anesthesiologists, nurse anesthetists (crnas) * first responders (i.e. emts, paramedics)

inclusion criteria: - a healthcare worker at high risk for covid-19 exposure (defined below): - persons primarily working in emergency departments (physicians, nurses, ancillary staff, triage personnel) - persons primarily working in intensive care units (physicians, nurses, ancillary staff, respiratory therapists) - persons performing aerosol generating procedures (i.e. anesthesiologists, nurse anesthetists (crnas) - first responders (i.e. emts, paramedics)

inclusion criteria: - a healthcare worker at high risk for covid-19 exposure (defined below): - persons primarily working in emergency departments (physicians, nurses, ancillary staff, triage personnel) - persons primarily working in intensive care units (physicians, nurses, ancillary staff, respiratory therapists) - persons performing aerosol generating procedures (i.e. anesthesiologists, nurse anesthetists (crnas) - first responders (i.e. emts, paramedics)