Hospitals, doctors and clinics expressed frustration that they will have to wait even longer for reimbursements after hackers paralyzed the largest U.S. billing clearinghouse.

Read More Health Insurance and Managed Care, Hospitals, Drugs (Pharmaceuticals), Cyberattacks and Hackers, Drugstores, Computers and the Internet, UnitedHealth Group Inc, Medicare, Doctors, ALPHV/BlackCat, Federal Bureau of Investigation, American Hospital Assn, Health and Human Services Department