A mounting US death toll has tempered enthusiasm about a coming Covid-19 vaccine with 9/11-like fatalities projected every day for the months ahead, even with a rapid rollout of inoculations, which could start as soon as Monday.
The country is poised to hit a record 16 million cases in the coming days, with deaths closing in on the 300,000 mark.
The first vaccine was approved late on Friday by the US Food and Drug Administration and is expected to touch off a mass-inoculation campaign of unparalleled dimension to end the pandemic that has upended daily life and devastated the US economy.
"FDA APPROVES PFIZER VACCINE FOR EMERGENCY USE!!!" President Donald Trump announced on Friday night on Twitter. He promised Americans the vaccinations would begin in less than 24 hours.
But US Army General Gustave Perna said on a Saturday news call that the first shipments will begin on Sunday and will be delivered to 145 locations around the country on Monday.
The remainder of the 636 delivery locations selected by states and US territories will receive doses on Tuesday and Wednesday, he said, adding that Pfizer will have more doses ready every week for distribution and administration.
The first batch of shots is expected to be aimed largely at health care workers and residents and staff of long-term care facilities.
The approval of the Pfizer drug by the US Food and Drug Administration marks a turning point in the United States, where the pandemic has killed more than 295,000 people - more than in any other nation in the world - as the recent surge of infections has again overwhelmed healthcare systems.
The country reported its highest daily cases, more than 232,700, on Friday, according to a Reuters tally. In the latest 7-day average, the United States is reporting 2,411 deaths per day, the highest 7-day average since the pandemic started.
US coronavirus hospitalisations were 107,684 by the end of Friday, the highest so far.
On Nov. 21, the United States hit a landmark 12 million cases.
New York Governor Andrew Cuomo, who along with several other governors vowed to review the vaccine before allowing it in their states, announced late on Friday that state officials have given the drug the green light.
"The vaccine, that is the weapon that ends the war," Cuomo said in a press briefing on Saturday.
But he warned that it might be June or later before life will start to return to normal as more of the US population receives the drug.
Urging people to be patient, Cuomo said, "Between today and June, that's a long way."