Mr Biden turned around slowly and bluntly replied: “I just explained that I think thoroughly, I hope I did anyway.”
Another reporter asked a follow-up question and wondered if some states should pause their reopening efforts.
Once more, the President turned around and bluntly replied: “Yes.”
Commentators below the video ridiculed the President who has repeatedly made errors during public appearances.
One wrote: “I don’t understand what he said.”
Another added: “It’s almost like he’s not even President.”
More commented and said Biden was getting “worse by the day” and wondered how he would manage another three years in office.
During his press conference, Biden revealed 90 percent of US adults would be eligible for a vaccine in the next few weeks as America ramps up its programme.
Some states in the US have begun reopening after weeks of lockdown.
But Mr Biden also called for renewed mask mandates to be put in place to curb the spread of the coronavirus and urged states to slow down their reopening.
The US is also developing vaccine passports to reopen parts of the country and to prove that citizens have received their jab.
The rollout could see other nations following suit as the topic of vaccine passports have circled Westminster and the European Union as a way to reopen the travel and tourism industry.