Health officials are concerned that data from a large medical database may have been compromised, possibly affecting more than a million people.
A large database containing information from health and other government agencies was hacked and may have included patient information.
The database includes information from about 4.6 million Medicare and Medicaid enrollees, but data was compromised, the Centers for Medicare and Medicare Services said in a statement Thursday.
The agency said there were no immediate reports of health-related injuries or deaths from the breach, and there was no evidence that anyone has been harmed.
The federal agency did not say whether anyone was still enrolled in Medicare or Medicaid, or how many people were affected.
The National Security Agency (NSA) was also not involved in the breach.
The breach of HealthCare.gov was discovered after the site was initially launched, but a fix was not made available until Wednesday, said the agency.
In a blog post, the agency said it would not release the names of individuals who were affected by the breach because they have not been identified.
But the government agency said a total of 4.4 million Medicare beneficiaries may have had their information compromised.
The number was significantly lower than the agency’s estimate that 4.8 million had their data.
The data included information on beneficiaries’ insurance status, medical history, medications and health insurance policies, as well as payment history, and other financial data, according to the agency, which did not identify the breach or give a reason for it.
The Federal Emergency Management Agency, which oversees federal disaster preparedness, said it was assisting the government.
The site was not fully operational until Tuesday, when it was updated with information on Medicaid eligibility, health status and payment history.
The site has been offline for the last three days.
The Department of Veterans Affairs said that people who were enrolled in its system may have also been affected.”VA has been informed of a data breach involving HealthCare, VA.gov.
We are actively investigating the incident and will provide updates as appropriate,” VA said in an email to ABC News.
The department said it is working to secure access to the website.
Affected people can get help with enrolling in Medicare, Medicaid and the Veterans Health Administration by contacting the U, VA and the UPMC websites.
If you or someone you know is experiencing any of the issues, contact the U Health HealthCare Service at 866-931-0240 or the VA online at www.va.gov or call toll-free at 1-877-273-8255.