US health group hit with major data breach

New York - Tens of millions of US patients' information such as Social Security numbers have been stolen from Anthem, the company said on Wednesday, in the worst hacking revealed by a health insurer to date.

"Cyber attackers executed a very sophisticated attack to gain unauthorised access to one of Anthem's IT systems and have obtained personal information relating to consumers and Anthem employees who are currently covered, or who have received coverage in the past," a statement from the second-largest US health insurer said.

"The information accessed includes names, birthdays, social security numbers, street addresses, email addresses and employment information, including income data."

The numbers of people hit by the data breach are in the tens of millions said a company spokesperson.

"The affected database has records for 80 million people and tens of millions" of them were stolen, spokesperson Cindy Wakefield said.