Datasets:

EPI-Eval
/

cdc-nssp

pretty_name: CDC NSSP / ESSENCE — ED visits for ILI / COVID / RSV (aggregate)
license: other
size_categories:
  - 10K<n<100K
tags:
  - cadence-weekly
  - geo-us
  - surveillance-syndromic
  - pathogen-influenza
  - pathogen-sars-cov-2
  - pathogen-rsv
  - tier-1
  - availability-open
schema_version: '0.1'
source_id: cdc-nssp
source_url: >-
  https://data.cdc.gov/Public-Health-Surveillance/2023-Respiratory-Virus-Response-NSSP-Emergency-Dep/vutn-jzwm
manifest_section: §1.8
surveillance_category: syndromic
pathogens:
  - influenza
  - sars-cov-2
  - rsv
availability: open
availability_notes: null
access_type: socrata
tier: 1
cadence: weekly
geography_levels:
  - national
  - subnational-state
geography_countries:
  - US
gold_standard_for: []
vintaged_version_of: null
succeeds: null
derived_from: []
value_columns:
  - name: percent_visits
    unit: percent (0-100)
    value_type: proportion
    description: >-
      Percentage of ED visits with chief complaint or diagnosis matching the
      syndromic case definition for the row's `condition`.
    aggregation: proportion
notes:
  extra_columns:
    - column: location_name
      description: >-
        Source's full state name (or "United States"). Kept for traceability;
        `location_id` is canonical.
    - column: condition_native
      description: >-
        Source's pathogen label as published (`Influenza`, `COVID-19`, `RSV`).
        Mapped to canonical `condition` slug for cross-source filtering.
  interpretation_caveats:
    - column: percent_visits
      caveat: >-
        Syndromic — based on chief complaint or diagnosis codes at ED triage,
        not lab confirmation. Sensitive to coding practices, which vary by
        hospital and state. Not directly comparable to NHSN HRD's
        `totalconfflunewadm` (lab-confirmed admissions) or ILINet's `wili`
        (sentinel outpatient ILI).
    - column: condition
      caveat: >-
        `sars-cov-2` here means 'ED visits with COVID-19 syndromic match', not
        'PCR-confirmed COVID admissions'. Same for `influenza` and `rsv`.
  general: >
    NSSP (National Syndromic Surveillance Program) covers a large fraction of US
    ED visits

    via the BioSense platform / ESSENCE. This Socrata feed is a state-aggregated
    weekly

    summary of three respiratory pathogens; finer-grained NSSP data (sub-state
    HSA, broader

    case definitions) is gated and not exposed here.


    South Dakota does not participate in NSSP and is absent from this feed.
    State

    participation has expanded over time, so historical sparsity differs by
    state.
extra:
  socrata_endpoint: https://data.cdc.gov/resource/vutn-jzwm.json
  delphi_alternative: >-
    Delphi epidata exposes the same NSSP data via the `nssp` endpoint with full
    vintaging support. A future `cdc-nssp-vintaged` source could provide the
    as-of history.
  source_columns_omitted: 0 (all 4 source columns retained as either canonical or extra columns)
computed:
  last_ingested: '2026-04-25T23:03:27Z'
  row_count: 19950
  time_coverage:
    - start: '2023-10-07'
      end: '2026-04-18'
  geography_unit_count: 50
  observed_cadence_days: 7
  missing_gaps: []
  data_hash: 6e1674942505ecdf

CDC NSSP / ESSENCE — ED visits for ILI / COVID / RSV (aggregate)

NSSP (National Syndromic Surveillance Program) covers a large fraction of US ED visits via the BioSense platform / ESSENCE. This Socrata feed is a state-aggregated weekly summary of three respiratory pathogens; finer-grained NSSP data (sub-state HSA, broader case definitions) is gated and not exposed here.

South Dakota does not participate in NSSP and is absent from this feed. State participation has expanded over time, so historical sparsity differs by state.

Source: https://data.cdc.gov/Public-Health-Surveillance/2023-Respiratory-Virus-Response-NSSP-Emergency-Dep/vutn-jzwm

Coverage

Time: 2023-10-07 → 2026-04-18
Cadence: weekly (observed median spacing: 7 days)
Geography levels: national, subnational-state — 50 unique location IDs
Countries: US
Pathogens: influenza, sars-cov-2, rsv
Surveillance category: syndromic
Rows: 19,950

Columns

Column	Unit	value_type	Aggregation	Description
`percent_visits`	percent (0-100)	`proportion`	`proportion`	Percentage of ED visits with chief complaint or diagnosis matching the syndromic case definition for the row's `condition`.

Additional data columns

location_name — Source's full state name (or "United States"). Kept for traceability; location_id is canonical.
condition_native — Source's pathogen label as published (Influenza, COVID-19, RSV). Mapped to canonical condition slug for cross-source filtering.

Interpretation caveats

Things that may differ from how other sources define a similar measure. If you're combining this dataset with another, read these first.

percent_visits — Syndromic — based on chief complaint or diagnosis codes at ED triage, not lab confirmation. Sensitive to coding practices, which vary by hospital and state. Not directly comparable to NHSN HRD's totalconfflunewadm (lab-confirmed admissions) or ILINet's wili (sentinel outpatient ILI).
condition — sars-cov-2 here means 'ED visits with COVID-19 syndromic match', not 'PCR-confirmed COVID admissions'. Same for influenza and rsv.

Access

Availability: open
Access type: socrata
License: other
Tier: 1

Schema version 0.1 · Last ingested 2026-04-25T23:03:27Z · source_id: cdc-nssp · Manifest section §1.8