A window into the data work behind this tracker.
One free API for the website and for other tools.
This is the exact accepted record served by the summary API. The parser extracts the report date, year, scope and count from the captured official page, then validates resident/visitor totals. The retrieval timestamp remains separate from the report date.
As of September 17, 2026, 3,471 confirmed* measles cases were reported in the United States in 2026.Read the original at CDC
Source: CDC. Original material is available free on the CDC website. Use does not imply CDC, HHS, or U.S. Government endorsement.
{
"canonical_url": "https://www.cdc.gov/measles/data-research/index.html",
"data_as_of": "2026-09-17",
"definition": "Cumulative confirmed cases; not infections today",
"geo_id": "US",
"measure": "confirmed_cases",
"outbreak_status": "not_specified",
"parser_version": "cdc-bundle/2",
"period_basis": "CDC surveillance year by rash-onset epidemiologic week; period bounds label the reporting year, not individual onset dates",
"period_end": "2026-09-17",
"period_start": "2026-01-01",
"raw_format": "cdc-source-bundle/1",
"scope": "all_reported_in_US",
"source_excerpt": "As of September 17, 2026, 3,471 confirmed* measles cases were reported in the United States in 2026.",
"source_id": "cdc",
"source_published_at": null,
"source_updated_at": "2026-09-18",
"status": "reported",
"supporting_sources": [
{
"sha256": "32f99bcaf5ebc5aadf99485d2a223efe527bb5ebfc3d1268ea2b630d6644a316",
"url": "https://www.cdc.gov/measles/data-research/index.html"
},
{
"sha256": "7ac01c5d399112ada254ee2d911bb402f5100d43ebf3a15c5aabe8818044c947",
"url": "https://www.cdc.gov/measles/states-cases-2024.json"
},
{
"sha256": "0de8925fd92fbc49e424c9791080d7e5cbf392f323563f09d47b2a89c2e835ec",
"url": "https://www.cdc.gov/wcms/vizdata/measles/MeaslesCasesMap.json"
}
],
"value": 3471,
"revision": 20,
"snapshot_id": 4,
"sha256": "1ca2531252fe3843da341fd510efa4516f2a9cc314ee1eaf8b5020a2e582169b",
"fetched_at": "2026-09-21T20:33:02.585401+00:00"
}SHA-256 1ca2531252fe3843da341fd510efa4516f2a9cc314ee1eaf8b5020a2e582169b
SHA-256 of retained lossless CDC bundle; supporting_sources contains each original response hash
The server counts successful, rejected, failed, and cached API requests. Fetching an upstream source is a separate event. Anonymous traffic does not establish an agent’s identity. These are aggregate totals from this local database; no IP histories, payments, accounts, or keys.
HTML page views and internal rendering do not increment these API totals. A GET to the usage API appears in its next read. A shared anonymous rate limit returns 429 with Retry-After; it is abuse protection, not billing.
curl http://127.0.0.1:8787/api/v1/summary curl "http://127.0.0.1:8787/api/v1/county-layer"OpenAPI 3.1 document ↗
null means there is no publishable value. Suppressed and unreported are explicit statuses. A reported zero is the number 0.
data_as_of belongs to the official report. fetched_at says when it was retrieved. Staleness and source failures are separate fields.
News does not change official case counts. There is no public ingestion or administration endpoint.