(CNN) -- President Joe Biden on Thursday stressed the need to vaccinate the 66 million Americans who have not received their Covid-19 vaccination shots as he touted falling case numbers across the nation.
During brief remarks from the White House, Biden argued that vaccine requirements, which he has promoted for weeks, have been effective.
"Now is not the time to let up. We have a lot more to do. We're in a very critical period as we work to turn the corner on Covid-19," Biden said, speaking from the White House.
The President said: "First, we have to do more to vaccinate the 66 million unvaccinated people in America. It's essential. The vaccine requirements that we started rolling out in the summer are working. They are working."
Biden delivered remarks after he and Vice President Kamala Harris received a briefing from members of the White House Covid-19 Response Team in the Oval Office.
The President updated the public on his national vaccination program as vaccine advisers to the US Food and Drug Administration discuss whether to authorize boosters of Moderna's coronavirus vaccine for some adults. Last month, the FDA authorized booster doses of Pfizer's vaccine for certain people.
Biden touted his administration's response to the pandemic as cases and hospitalizations continue to decline, the official said. He will stress the importance of keeping up the pressure and getting the rest of the country vaccinated, according to the official.
About 188 million people, or 66.2% of the eligible US population, is fully vaccinated, according to the US Centers for Disease Control and Prevention. About 66 million people, or 23.3% of the eligible population, have not received a Covid-19 vaccine.
Biden has touted vaccination requirements in the private and public sector as an effective way to get more people vaccinated, and has expressed frustration with the tens of millions of Americans who have not received their vaccine and are fueling the spread of the virus.
Last month, the President announced stringent new vaccine rules on federal workers, large employers and health care staff in an attempt to contain the latest surge of the virus.
The new requirements could apply to as many as 100 million Americans, which is close to two-thirds of the American workforce.
White House Covid-19 Response Coordinator Jeff Zients said Wednesday that more than 3,500 organizations have adopted vaccine requirements, including major health systems, educational systems and private businesses. Zients said those mandates have increased vaccination rates by 20-plus percentage points, with organizations routinely seeing their share of fully vaccinated workers rise to above 90%.
Biden will also speak about his administration's efforts to keep schools open amid the pandemic, the official said.
CDC Director Dr. Rochelle Walensky on Wednesday said the agency has been meeting with states to discuss a potential "test-to-stay" strategy in schools. Instead of quarantining students who have been exposed to the virus, students would get tested and if their result is negative they could stay in school and attend class.