The California lawmaker said she got sick over the February recess.
California Sen. Dianne Feinstein has been hospitalized in her home state with shingles.
A spokesperson for her office on Thursday confirmed her hospitalization, which was first reported by The San Francisco Chronicle.
“I was diagnosed over the February recess with a case of shingles. I have been hospitalized and am receiving treatment in San Francisco and expect to make a full recovery,” Feinstein said in a statement. “I hope to return to the Senate later this month.”
Shingles is caused by the same virus, varicella-zoster virus, that causes chickenpox and is characterized by a painful rash that develops on the face or body. A person sickened by chickenpox and who recovers can later get shingles when the virus reactivates.
While about one in every three people in the U.S. develops shingles, according to the Centers for Disease Control and Prevention, only about 1-4% need to be hospitalized.
At 89, Feinstein is the oldest serving member of the Senate. She has not been on Capitol Hill this week.
Her absence is a further blow to the narrow Democratic majority, with Pennsylvania Sen. John Fetterman out for an indefinite amount of time being treated for depression.
If all Republicans are present and voting next week when the chamber returns, they’ll have a one-vote majority, though Senate Majority Leader Chuck Schumer controls the floor.
Last month, Feinstein announced that she would not run for reelection after her term is up in early 2025 but will continue serving until then and “intend[s] to accomplish as much for California as I can.”
She said then that she remains focused on passing legislation important to Democrats through the end of her term, including curbing gun violence in the face of a string of mass shootings and ameliorating homelessness and wildfires.
After announcing her retirement to her colleagues during a closed-door lunch, Feinstein spoke briefly to reporters, saying, “The time has come.”
California Reps. Barbara Lee, Katie Porter and Adam Schiff have all announced bids to succeed her.
ABC News’ Tal Axelrod, Trish Turner and Nicole Wetsman contributed to this report.