The two-week cumulative incidence rate summarizes new cases reported in the past 14 days per 100,000 people. It looks at the recent burden of cases in an area given its population. Areas with elevated incidence rates will have a higher burden of ill people who may be infectious and/or currently accessing healthcare.
The current epidemic curve looks at how the trend in cases is changing over time and assigns a trend category to each day, based on whether the three-day daily average of cases is increasing, staying stable, or decreasing. It is calculated by using the daily case incidence rate per 100,000 people (bars), finding the three-day moving average of daily incidence rates (grey points), fitting a smoothed curve to these incidence rates (grey line), and looking at the slope of that curve (colors on the bars). If the slope of the curve is above zero, incidence is increasing. If the slope is about zero, incidence is holding stable (a plateau). If the slope is decreasing after at least five days of plateau, incidence is decreasing.
Please note: Recent increases or decreases in testing can lead to changes in daily incidence. Epidemic curve status can fluctuate from day to day so trends need to be interpreted cautiously and in conjunction with other surveillance data.
The graphs below show data reported by Emergency Departments (EDs) which submit syndromic surveillance data to the National Syndromic Surveillance Program (NSSP) at the CDC. Currently, 49 EDs submit data in Utah. These data reflect the 7 day average of both the total number of visits and the percent of visits that match CDC’s national syndromic definitions for COVID-19, Influenza, and RSV. These definitions only consider the diagnosis discharge codes for each condition, since January 1, 2019. These data are reported prior to a person being tested and are intended to provide indications of trends occurring throughout Utah. The numbers and percentages presented are based on the patient’s address of residence when visiting an ED. For example, if a Davis County resident visits a Salt Lake County ED, the count will be associated within the Davis County numbers.