(NewsNation) — President Joe Biden left Delaware, where he was recovering from COVID-19 following his decision to end his campaign, and arrived at the White House Tuesday night.

Biden tested negative for the virus as of Tuesday, according to a letter from his physician.

“The president’s symptoms have resolved,” the letter stated. “Over the course of his infection, he never manifested a fever, and his vital signs remained normal.”

Biden told reporters he was “feeling well” before boarding Air Force One on Tuesday. It was the first time the news media had spotted Biden since Wednesday night.

“It’s great to be back at the White House,” he shared on X, formerly known as Twitter, hours later.

The president’s first public speech since then could be his upcoming Oval Office address, which is scheduled for 8 p.m. ET Wednesday.

Biden had been attending virtual meetings and performing all his duties as he isolated, according to his staff. A White House official told NewsNation the president is expected to meet with Israeli Prime Minister Benjamin Netanyahu this week, as is Vice President Kamala Harris.

Biden’s absence follows his letter announcing his withdrawal from the presidential race.

Biden’s struggling campaign

Following the first presidential debate, worried Democrats began calling on Biden to resign due to his poor performance and concerns he would not be able to win in November.

Voters also expressed worries about Biden’s age and mental fitness, which the campaign tried to address in a series of interviews, campaign events and official duties.

Those efforts, however, were marred with verbal gaffes and performances that led to an increasing number of Democrats to urge Biden to step aside. The campaign received another blow when Biden tested positive for COVID-19, leading him to isolate at his home and cancel campaign events.

While the president remained committed to running in the days following the debate, the tide turned over the weekend. In a letter, Biden announced he would be stepping back and gave his endorsement of Harris as the new nominee.

What happens next for Democrats?

While Biden’s support for Harris will certainly have an impact, she isn’t automatically going to take his place on the ticket.

With Biden’s announcement, his delegates will now be open to supporting a nominee. For many, Harris is the obvious choice, given her experience and previously presumed place on the ballot as vice president.

But the Democratic National Convention and an advance virtual vote made necessary by Ohio’s election laws haven’t happened yet. While many notable Democrats have stepped forward with endorsements for Harris, there’s also a chance delegates could put forth other nominees.

Many of the names floated — including Pennsylvania Gov. Josh Shapiro, Kentucky Gov. Andy Beshear and North Carolina Gov. Roy Cooper — could also be contenders for the vice presidential spot alongside Harris.

When will Biden be back?

Biden’s campaign had already suspended advertising following an assassination attempt on former President Donald Trump in Butler, Pennsylvania. That, combined with the president’s COVID-19 isolation, led to quiet as Biden considered his future.

In his letter, Biden teased an address to the nation sometime this week, and on Tuesday he announced the speech would come on Wednesday night.

Another outstanding schedule item is an address the president was set to give commemorating the 60th anniversary of the Civil Rights Act. Originally set to take place at the LBJ Presidential Library, the speech was canceled due to the Trump rally shooting.

While the president recovered, Harris stepped up her schedule, meeting with top Democrats and hosting campaign events in advance of the convention.

NewsNation’s Kellie Meyer contributed to this report.