References and Sources

Local COVID-19 Prevalence

The default value is based on active infection data for the U.S. as a whole. State specific information can be found by going to the COVID-19 CDC web-page below. 
Some calculation will be required. To get a rate, simply divide the number of active cases by the specific population, and multiply by 100 to get the percentage.

https://covid.cdc.gov/covid-data-tracker/?utm_source=morning_brew#cases

COVID-19 PCR Test Sensitivity

PCR test sensitivity can vary by test type and location. 70% has been chosen as a reasonable estimate for most testing in the United States. Please see the following journal article for more in-depth information.

Variation in False-Negative Rate of Reverse Transcriptase Polymerase Chain Reaction–Based SARS-CoV-2 Tests by Time Since Exposure
https://www.acpjournals.org/doi/10.7326/M20-1495

COVID-19 & Healthcare Professionals

Numbers from the CDC regarding cases and deaths among healthcare professionals can be found on the web-page below:

https://covid.cdc.gov/covid-data-tracker/#health-care-personnel