Emergency Department Visit Trends for Respiratory Pathogens by U.S. Region

NSSP Emergency Department Visit Trajectories provides weekly percentages of ED visits for COVID-19, flu, and RSV across U.S. states and Health Service Areas. The dataset classifies trends as increasing, decreasing, stable, or sparse based on statistical modeling of syndromic surveillance data. It is updated weekly by the U.S. Department of Health & Human Services.

Use Cases

• Model the relationship between weekly trend classifications (increasing, decreasing, stable) and pathogen type (COVID-19, Flu, RSV) across geographic regions.
• Analyze the spatial distribution of 'sparse' data classifications to identify Health Service Areas with insufficient reporting for model fitting.
• Track the weekly percentage of ED visits attributed to a combined respiratory illness metric over time for public health surveillance.
• Compare state-level and sub-state (HSA) trajectory classifications to assess regional variations in respiratory virus spread.

Strengths

• Data is updated weekly on Fridays, providing near real-time surveillance.
• Trends are derived from statistical models (generalized additive models) with 95% confidence intervals, adding analytical rigor.
• Coverage includes multiple respiratory pathogens (COVID-19, Flu, RSV) and a combined metric for comprehensive illness tracking.
• Geographic granularity extends to sub-state Health Service Areas (HSA), enabling localized analysis.

Limitations

• Trend classifications for HSAs are not computed when data is deemed too sparse (many weeks with 0%), limiting analysis for some regions.
• The underlying row count, column structure, and sample size are unspecified, making it difficult to assess data volume and feature set.
• As a derived, aggregated dataset, it does not contain raw patient-level ED visit records.

Provenance

Source

U.S. Department of Health & Human Services, National Syndromic Surveillance Program (NSSP)

Collection Method

Aggregated from emergency department visit data submitted to the NSSP, with trends modeled using generalized additive models (GAMs).

Freshness

Updated weekly on Fridays.

Geography

United States, by state and sub-state Health Service Areas (HSA).