The WCCHD flu surveillance system does not attempt to capture all cases
of influenza or influenza-like illness. The number of reporters sending in flu reports may vary from week to week. These data should be used to look for trends over time rather than for estimating the total number of cases.
Flu activity categories are calculated based on guidance from CDC
. The data presented each week are preliminary and may change as more data is received. Data will be refreshed weekly on Tuesdays.
Data on ILI is collected throughout the season from a variety of sources. On a weekly basis, school districts report to WCCHD absences due to ILI. Hospitals report numbers of patients seen with ILI and/or flu (rapid test by type: A, B, or not differentiated). Lone Star Circle of Care reports total counts of ILI seen in their clinics, and they provide additional data derived from their electronic medical record system aggregated by age, gender and zip code of residence. RediClinics and Texas MedClinic report total ILI seen to CDC’s ILINet and their data is available to WCCHD one week later. In addition, hospital emergency departments report chief complaint data to a syndromic surveillance system. Occasionally, other health departments relay information on cases from Williamson County seen by providers in other jurisdictions. Information related to each of these data streams is reviewed and analyzed by WCCHD weekly for trends.
Useful Resources & References