Vaccinations are proceeding, even accelerating, but COVID-19 cases are rising, and Americans should remain very concerned, President Biden and members of his administration warned on Monday:

"Our work is far from over. The war against COVID-19 is far from won. This is deadly serious," President Biden said.

"We share the sentiment of Dr. Walensky, the head of the Center for Disease Control and--and Prevention. The CDC expressed earlier today this is not a time to lessen our efforts. That's what she said. We could still see a setback in the vaccination program. And most importantly, if we let our guard down now we could see a virus getting worse, not better."

'Feeling...of impending doom'

Dr. Rochelle Walensky, going off-script at a different news conference earlier on Monday, told Americans she's "scared."

"And I'm going to reflect on the recurring feeling I have of impending doom," Walensky said. "We have so much to look forward to, so much promise and potential of where we are, and so much reason for hope. But right now, I'm scared."

Walensky talked about her experience with dying patients, with hospitals running out of supplies, with makeshift morgues set up outside: