The cyberattack at UnitedHealth Group's (NYSE:UNH) tech unit last year, which paralyzed the U.S. healthcare system, exposed the personal information of about 190 million people. The nation's largest health insurer said Change Healthcare was not aware of any misuse of individuals' data as a result of the incident.

The cyberattack at UnitedHealth Group's tech unit last year affected the personal information of 190 million people, the health conglomerate said on Friday, making it the largest healthcare data breach in the United States.

UnitedHealth has confirmed the ransomware attack on its Change Healthcare unit last February affected around 190 million people in America — nearly double previous estimates. "Change Healthcare has determined the estimated total number of individuals impacted by the Change Healthcare cyberattack is approximately 190 million,

A cyberattack on UnitedHealth Group Inc. that paralyzed the US health-care system last year, snarling billions of dollars in payments for doctors and hospitals, also exposed sensitive data from 190 million Americans.

The attack, originally thought to have impacted about a 100 million Americans, is even larger than originally disclosed.