ATTACK2024-02-21 · Change Healthcare / UnitedHealth Group · US-wide · 21 days

The Day the Claims Stopped

Change Healthcare, ransomware, and the anatomy of a single point of failure

TL;DR

In February 2024, ransomware took down Change Healthcare — a clearinghouse most patients had never heard of that touched roughly a third of U.S. claims. Pharmacies reverted to cash and paper; small practices went weeks without revenue. The clearest demonstration yet that healthcare's most critical systems are the ones nobody can see.

TL;DR

[Write the 3-sentence TL;DR here — this can restate or expand on the tldr frontmatter field above, since that field also drives the case card on the Observatory index.]

Timeline

[Five labeled moments, in order. First one is the incident (red), the rest are gold. Example format:

  1. 2024-02-21 — Ransomware detected, systems taken offline
  2. …]

The System

[What was this system, who relied on it, why did it matter? Plain, confident, first person.]

The Stress

[What actually happened — the event itself.]

Points of Failure

[The failure. Be specific: what stopped working, for whom, for how long.]

Points of Resilience

[Equal weight to “Points of Failure.” What kept working, what people or systems improvised, what safety nets caught the fall. Teal always means resilience — don’t skip this section.]

What It Teaches

[Numbered takeaways.

  1. …]

Sources

[Numbered, primary sources first.

  1. …]

Last reviewed 2026-07-14 · Public sources only