The president tested negative for COVID on Monday a day after he had been in close contact with a White House staff member who had tested positive for the virus.

Biden appeared to cough and excused himself twice while speaking about his administration’s plans to deal with COVID amid the surge of the Omicron variant in the U.S. He also appeared to briefly have a catch in his throat.

“I know there are some parts of this country where people are very eager to get their booster, where it’s harder to get an appointment. Excuse me,” Biden said, coughing into his hand.

He soon coughed again while discussing Federal Emergency Management Agency (FEMA) vaccination sites and later seemed to catch his breath while talking about military medical teams.

Some social media users highlighted Biden’s cough and expressed concern about it.

Bruce Coleridge-Taylor Wright, editorial director of NewsOne, shared a gif of Biden putting on a face mask and wrote: “Biden coughing while addressing the nation about Covid and omicron…”

Lawyer Exavier Pope tweeted: “President Joe Biden was coughing in his presser. Wouldn’t be shocked if Omicron paid him a visit. This variant is so contagious.”

Joe Concha, media and political columnist for The Hill, wrote: “The president continues to cough throughout this speech,” while conservative columnist Todd Starnes asked “Does Biden have a COVID cough?”

MSNBC Daily writer and editor Hayes Brown shared a gif of characters from the TV show Supernatural looking concerned and tweeted: “me, every time Biden coughs or clears his throat during this address.”

The 79-year-old president is fully vaccinated and has received a booster shot, and he is also regularly tested.

White House press secretary Jen Psaki issued a statement on Monday saying that a “mid-level staff member” had tested positive for COVID-19 and while the person in question does not regularly have contact with Biden, they had spent about 30 minutes near the president on Air Force One on Friday.

The staff member had tested negative before boarding Air Force One but subsequently tested positive on Monday. Biden received a PCR test on Monday and tested negative. He will receive another test on Wednesday. It is not known which variant of COVID the White House staff member contracted.

Before Biden delivered his address on Tuesday, Psaki told reporters: “He’s asymptomatic. I spent several hours with him this morning, and he is feeling great. And you’ll see him at the speech shortly.”

On December 3, Biden attributed coughing during a speech about the November jobs report to a cold he’d caught from his grandson. White House physician Kevin O’Connor issued a letter at the time saying the president was suffering from “nasal congestion” and “frog in one’s throat.”

Newsweek has asked the White House for comment.