Illinois Respiratory Illness Hospital Visits by Week, Demographics, and Activity Level

The Illinois Department of Public Health (IDPH) and Chicago Department of Public Health (CDPH) aggregate weekly data on emergency department, inpatient, and outpatient visits for influenza-like illness (ILI), COVID-19, influenza, RSV, and acute respiratory illness. Data is collected from 185 acute care hospitals in Illinois via the CDC's BioSense Platform and from outpatient clinics in the ILINet network. The dataset includes demographic breakdowns and respiratory illness activity levels for emergency department visits from MMWR Week 202427 onward.

Use Cases

• Track weekly trends in respiratory illness visits using week_start, week_end, and percent columns.
• Compare disease burden across demographic groups using demographic_group and demographic_category columns.
• Analyze healthcare setting utilization for different illnesses using visit_type and respiratory_category columns.
• Assess public health activity levels for influenza, COVID-19, and RSV using the activity_level column.
• Correlate outpatient ILI surveillance (data_source) with hospital-based metrics (essence_category).

Strengths

• Data is sourced from all 185 acute care hospitals in Illinois, providing a statewide view.
• Includes multiple respiratory illness categories (COVID-19, influenza, RSV, ARI) and three healthcare settings (inpatient, ED, outpatient).
• Features demographic stratification by age group and race/ethnicity via demographic_group and demographic_category columns.
• Integrates a standardized CDC activity_level metric for emergency department visits from mid-2024.

Limitations

• Row count and dataset size are unknown, which may limit suitability assessment.
• Data is provisional and subject to change, as noted by the publisher.
• Description metadata is limited; actual data quality requires manual inspection after download.

Provenance

Source

Illinois Department of Public Health (IDPH), Chicago Department of Public Health (CDPH), CDC National Syndromic Surveillance Program (NSSP), CDC ILINet.

Collection Method

Aggregated from electronic health records submitted by 185 Illinois hospitals to the CDC BioSense Platform and from outpatient clinics in the ILINet network.

Time Range

Weekly data; activity_level data is included from MMWR Week 202427 (week starting 6/30/2024) forward.

Freshness

Last updated 2026-05-22 17:34:21.

Geography

State of Illinois, with specific outpatient data from Chicago.