U.S. Outpatient Influenza-Like Illness Activity by State and Week

More than 100 million patient visits were reported during the 2022-23 season. This dataset contains weekly activity levels for influenza-like illness (ILI) across U.S. states and territories, derived from reports by over 3,000 outpatient healthcare providers. It was published by the CDC via data.cdc.gov and was archived, with no further updates after October 16, 2024.

Use Cases

• Analyze temporal trends in respiratory illness by plotting the `activity_level` against `week_ending` for a specific `state`.
• Compare seasonal intensity by aggregating `activity_level_label` (e.g., 'high', 'very high') across different `season` values.
• Identify geographic hotspots by mapping the `activity_level` or `activity_level_label` for each `state` during a peak `week`.
• Study age-stratified burden by linking jurisdiction-level activity to the underlying age-group visit data described in the methodology.

Strengths

• National coverage includes all 50 states, Puerto Rico, the District of Columbia, and the U.S. Virgin Islands.
• Derived from a large surveillance network of over 3,000 reporting outpatient healthcare providers.
• Provides a standardized `activity_level` (1-13) and `activity_level_label` for consistent cross-jurisdiction comparison.

Limitations

• Dataset is archived and will not be updated after October 16, 2024, limiting use for current surveillance.
• The number of reporting sites varies weekly, requiring baseline adjustments as noted in the methodology.
• Sample data and exact row counts are unavailable, making initial assessment of data volume difficult.

Provenance

Source

U.S. Centers for Disease Control and Prevention (CDC) via data.cdc.gov.

Collection Method

Data collected through the U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet), where providers report weekly patient visit counts for ILI and total visits.

Time Range

Covers multiple seasons up to the archive date; the 2022-23 season is specifically referenced.

Freshness

Final update was on 2024-10-16; the dataset is archived.

Geography

United States, including states, Puerto Rico, the District of Columbia, and the U.S. Virgin Islands.