The average daily incidence rate is calculated by taking the total number of unique cases in each zip code according to the CDC Morbidity and Mortality Weekly Report (MMWR), divided by seven to get a daily average, divided by the 2010 U.S. census bureau population and multiplied by 100,000 to get the incidence per 100,000 people. The cases counted each week are based on the date an investigation was opened in the Kentucky Contact Tracing and Tracking System. Duplicate cases are removed before the calculation, so each positive case is included only once.