The U.S. President Joe Biden on Wednesday emerged from five days of isolation after contracting the coronavirus, telling Americans that "COVID isn't gone" but saying serious illness can be avoided with vaccines, booster shoots and treatments.

Biden tested negative for the virus on Tuesday night and Wednesday morning.

"Back to the Oval," Biden tweeted after the White House released the latest daily update from his doctor confirming that he was clear to end the isolation period that is required after someone tests positive for the coronavirus.

Biden's tweet included a photo of a rapid COVID-19 test with the line showing a negative result.

Biden, 79, tested positive last week. He continued to work during isolation, holding meetings virtually and addressing groups through recorded messages.