---
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*