PORTLAND, Ore. (KOIN) – Oregon Senator Jeff Merkley announced he has re-tested positive for COVID-19 after initial infection in late May.

In a statement released on Thursday, the senator said he is experiencing mild symptoms and is following isolation guidelines from the CDC.

“After recovering and feeling better, some COVID symptoms have returned and I again tested positive. This is occurring in a modest percent of folks who used Paxlovid and is referred to as ‘COVID-19 rebound,’” Merkley said.

The senator added, “this is yet another reminder that the virus is evolving and changing, and we all must be diligent to stay one-step ahead. We know the best ways to mitigate the spread: getting vaccinated and boosted, wearing masks, and isolating and testing when you know you have been exposed.”

Merkley previously announced he tested positive for COVID-19 on May 23 after a close contact had it. During that time, the senator noted he also had mild symptoms.