In a letter to patients, Poway, Calif.-based Palomar Health Medical Group said it is investigating "suspicious activity on certain computer systems within its network," NBC San Diego reported May 7.
In the May 6 letter, Palomar said it detected the activity May 5 and took affected systems offline to prevent the spread of any potential malware. The outage is affecting Palomar's phones, faxes and patient portal.
Palomar is advising patients to go in person to their physician's office for new prescriptions and refills, and warning there could be delays in seeing their physicians, according to the letter.
The Palomar Health Healthcare District, which encompasses Palomar Medical Center Poway (Calif.) and Palomar Medical Center Escondido (Calif.), remains unaffected.
"Third-party specialists are working with Palomar Health Medical Group to investigate the source of this disruption, to confirm its impact on our systems, and to restore full functionality to our systems as soon as possible," Palomar told the publication. "We are also investigating what impact, if any, this incident had on the security of data within our environment."