UnitedHealth has confirmed that the data breach at Change Healthcare has impacted 190 million Americans.

UnitedHealth recently confirmed to TechCrunch on Friday after the markets closed that a ransomware attack on its subsidiary, Change Healthcare, in February 2024 impacted the data of around 190 million individuals in the United States, nearly doubling a prior estimate.

Tyler Mason, a UnitedHealth spokesperson, said Change Healthcare now estimates that roughly 190 million people were affected. Most of those were already notified, either directly or through substitute notices. The final total will be confirmed and reported to the Office for Civil Rights at a later date.

While the breach was huge, UnitedHealth has assured that it has not observed any misuse of personal information, nor was there any indication that medical record databases were accessed. This breach, now considered the largest healthcare data leak in U.S. history, disrupted U.S. healthcare services for months.

Change Healthcare, one of the largest providers of health technology and one of the largest processors of healthcare claims, deals in huge volumes of extremely sensitive medical and insurance data. The cyberattack resulted in the theft of huge amounts of health-related data, which hackers published partially online. To prevent further data leakage, Change Healthcare paid at least two ransoms to the attackers.

UnitedHealth had initially estimated that the breach could have affected as many as 100 million people. It was after an in-depth analysis that the revised estimate was available to the concerned authorities. “The breach notification provided by Change Healthcare further identifies stolen data containing personal data including, among others: names, addresses, dates of birth and contact data”. In addition, Social Security numbers, driver’s licenses number, as well as passport number were also pilfered. Health stolen information includes diagnosis and medication information and test results. Treatment plans apart, insurance information and financial records were also siphoned.

It was attributed to the ALPHV ransomware group, considered one of the most prominent Russian-language cybercrime groups. The hackers exploited an account credential that had been stolen and did not employ multi-factor authentication to access Change Healthcare’s systems.