The Global Signal Desk exists because outbreak and recall information is scattered across agencies that publish on different schedules, in different formats and with different definitions. The desk gathers what those agencies have published, links to it, and adds the context a reader needs to interpret it. This page describes the rules we follow and the limits we accept.
What a signal is
A signal is a dated record of a public-health event reported by at least one primary source, such as an outbreak investigation, a product recall or an environmental alert. Each signal links to its sources, states what the source says, separates our own analysis from the source text, and shows a confidence label and open questions. A signal can be updated, downgraded or closed. Resolved signals move to the archive rather than disappearing.
Source selection
- Primary first. Government health agencies (WHO, CDC, FDA, ECDC, national and state health departments) and the originating company for recalls take priority over news coverage.
- A specific primary or authoritative source is required. Secondary reporting, such as news coverage, can help us discover an event, but it is not enough on its own to create a signal.
- No anonymous tips, social-media rumors or private medical information are used as evidence.
Time stamps: observed, published, updated
Three dates can differ, and the desk keeps them apart. The source date is when the agency published or revised its page. The observed date is when the desk detected that version. The updated date is when we last made a material edit. A dated scan is a snapshot of what was known on that day, so it does not change when events later develop; the signal record does.
Confidence labels
Confidence describes the evidence, not the danger. A high-confidence signal means a primary source states the facts clearly and consistently. A lower-confidence signal may rest on preliminary counts, a source that is still being updated, or conflicting figures. Confidence reflects the evidence, not guaranteed truth, and is never a prediction of how an event will unfold.
Counts, definitions and geography
- We report the number a source states, with its cutoff date, and say whether cases are confirmed, probable or suspected.
- We keep different geographies apart. States where people became ill are not the same as states where a product was distributed, and a national total is not a local risk level.
- When two sources disagree, we show both and explain the discrepancy rather than averaging them.
- Percentages are given with their denominators, because a share of interviewed people is not a share of all cases.
What the desk does not do
- It is not real-time. Agencies publish with delay and so do we.
- It is not an official agency status page, and it does not replace your health department.
- It does not give clinical advice, diagnose illness or predict outbreaks.
- It does not guarantee human review. Automated scans assist collection, and staged changes are auto-approved, applied and logged in the review record. Always check the linked primary source.
- It does not identify private individuals or publish patient-level details.
Corrections and updates
If a material fact changes or we find an error, the signal shows an update note with what changed and when. Send corrections through the contact details on the about page. To repeat a check yourself, follow the investigation guide.