By Raphael Satter and Sriparna Roy
WASHINGTON (Reuters) -Pharmacies across the United States are experiencing disruptions following a hack at UnitedHealth (NYSE:UNH)'s technology unit, Change Healthcare (NASDAQ:CHNG), several pharmacy chains said in statements and on social media.
The problems began on Wednesday after a "suspected nation-state associated cybersecurity threat actor" gained access to Change Healthcare's information technology systems, UnitedHealth said in a filing on Thursday.
"Once we became aware of the outside threat, in the interest of protecting our partners and patients, we took immediate action to disconnect our systems to prevent further impact," Change Healthcare said on its status page. The company did not immediately respond to a request for further comment.
In its filing, UnitedHealth said it "cannot estimate the duration or extent of the disruption at this time." It said it had retained security experts and was working with law enforcement.
A variety of pharmacy chains said that the outage at Change Healthcare, a Tennessee-based provider of healthcare billing and data systems and a key node in the U.S. healthcare system, was having knock-on effects on their businesses.
CVS Health (NYSE:CVS), which has more than 9,000 pharmacies, said in a statement that the hack meant that, "in certain cases" it was unable to process insurance claims.
"We're committed to ensuring access to care as we navigate through this interruption," the CVS statement said. A spokesman for the chain didn't immediately respond when asked for further details.
Walgreens said a "small percentage" of its prescriptions "may be affected" but that the company had procedures in place to process and fill them "with minimal delay or interruption." The company said it had no additional information to share about the incident.
Publix Super Markets didn't immediately respond to a request for comment, but on social media some users complained of issues when trying to fill their prescriptions.
"This is a nationwide disruption," Publix said in a response to one user on X, formerly known as Twitter.
Other companies including GoodRX and BlueCross BlueShield of Montana also flagged potential disruptions on social media. Independent pharmacies also reported problems.
"Please be patient with us and all of the pharmacies affected by this," Dayton Drug and Wellness, a community pharmacy in Dayton, Tennessee wrote on its Facebook (NASDAQ:META) page.
"There have been/will be delays until this resolves," Skippack Pharmacy in Skippack, Pennsylvania said in another message posted to Facebook. "Pharmacies around the country are affected."
Healthcare services were also being disrupted, according to a director at a regional hospital system in Pennsylvania, who asked not to be identified because he wasn't authorized to speak to the media.
The U.S. cybersecurity watchdog agency CISA and the FBI did not return messages seeking comment.