The news: More than 100 million patients had health information stolen in a February ransomware attack on Change Healthcare, the provider and its owner, UnitedHealth Group, confirmed last week.

It’s the largest known healthcare data breach to date, affecting about a third of all people in the US.

Zooming out: Stolen data includes personal information such as names, Social Security numbers, and passport numbers, in addition to health data including medications, treatment plans, and diagnoses.