Is this real surveillance data?

Yes. It's the CDC's US Outpatient Influenza-like Illness Surveillance Network (ILINet) series as republished by the Delphi Epidata project at Carnegie Mellon — credited on screen as CDC FluView via Delphi Epidata (CMU).

Does it need an API key?

No. The Delphi Epidata API is public, key-less and CORS-enabled, so the browser fetches it directly.

FluView is compiled weekly and published with a lag of a week or more, and recent weeks are often revised as late reports arrive — so it's a live official series, not a realtime tracker.

Does it work offline?

No. It fetches the surveillance series over the internet; offline it shows a short notice instead of stale numbers.

What does the ILI percentage mean?

The weighted share of outpatient doctor visits where the patient had fever plus cough or sore throat — a symptom-based signal of flu activity, not a count of confirmed influenza cases.

Flu Surveillance Curve Screensaver

The Flu Surveillance Curve screensaver plots the real CDC FluView series — the weighted percentage of US outpatient visits for influenza-like illness, week by week — fetched in your browser from the key-less Delphi Epidata API at Carnegie Mellon. It's free, needs an internet connection, and ESC exits.

How the Flu Surveillance Curve screensaver works

The saver queries the Delphi Epidata API (api.delphi.cmu.edu) directly from your browser for national FluView data — no key, no pipeline.

It computes the CDC epiweek range itself, asking for the last one to three flu seasons from each season's week-40 start.

The weekly weighted-ILI percentage is drawn as one continuous curve with alternating season shading, so each winter's peak stands out against the summer floor.

The headline shows the latest reported rate and its epiweek; surveillance is compiled weekly and lags by a week or more, and recent weeks can be revised.

A worked example

In mid-January the curve typically climbs past 4–5% before rolling over in February — set three seasons of history and you can compare this winter's peak against the last two at a glance. In summer it flattens near 1%, which is exactly what the current 0.87% ILI style headline looks like.

Settings & tips

Seasons of history — how many flu seasons to plot, from just the current one to three back-to-back for peak-to-peak comparison.

Frequently asked questions

Is this real surveillance data?: Yes. It's the CDC's US Outpatient Influenza-like Illness Surveillance Network (ILINet) series as republished by the Delphi Epidata project at Carnegie Mellon — credited on screen as CDC FluView via Delphi Epidata (CMU).
Does it need an API key?: No. The Delphi Epidata API is public, key-less and CORS-enabled, so the browser fetches it directly.
How current is it?: FluView is compiled weekly and published with a lag of a week or more, and recent weeks are often revised as late reports arrive — so it's a live official series, not a realtime tracker.
Does it work offline?: No. It fetches the surveillance series over the internet; offline it shows a short notice instead of stale numbers.
What does the ILI percentage mean?: The weighted share of outpatient doctor visits where the patient had fever plus cough or sore throat — a symptom-based signal of flu activity, not a count of confirmed influenza cases.

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