U. S. OFFICIALS PREPARED FRIDAY FOR THE MOST AMBITIOUS VACCINATION CAMPAIGN IN DECADES AS REGULATORS AUTHORIZED USE OF PFIZER'S COVID-19 VACCINE TO SLOW A PANDEMIC NOW KILLING 3,000 AMERICANS PER DAY.

The U.S. Food and Drug Administration said it authorized the use of Pfizer Inc's COVID-19 vaccine on Friday, with the first inoculations expected within days, marking a turning point in the United States where the pandemic has killed more than 292,000 people.

The U.S. Food and Drug Administration granted an emergency use authorization for the vaccine, developed with German partner BionTech, which was shown to be 95% effective in preventing the disease in a late-stage trial.

The FDA said the vaccine can be given to people aged 16 and older. Healthcare workers and elderly people in long-term care facilities are expected to be the main recipients of a first round of 2.9 million doses.

The U.S. government has said it will begin distributing the vaccine around the country immediately after FDA authorization, and that the first inoculations would happen early next week.

Millions of Americans could begin getting vaccinated this month, especially if a second vaccine from Moderna Inc is quickly approved.

The Pfizer/biontech vaccine was first approved in Britain earlier this month, and U.K. residents began receiving the shots on Tuesday. Canada also authorized the vaccine and expects to start inoculations next week.

Mexico and Bahrain have also approved the vaccine.

The FDA authorization comes at a time when infections, hospitalizations and deaths are soaring to record levels in the United States, which has failed to mount a coordinated effort to slow the spread of the virus. Earlier this week, the one-day COVID-19 death total topped 3,000, while hospital intensive care units across the country are nearing capacity, threatening to overwhelm healthcare systems.

Others with vaccines in advanced development include Moderna, which could win emergency U.S. authorization as soon as next week, Astrazeneca Plc with Oxford University, and Johnson & Johnson.

Biontech began developing the vaccine in January, using a technology called synthetic messenger RNA (MRNA) that had yet to produce an approved product. The technology uses a chemical messenger to instruct cells to make proteins that mimic part of the new coronavirus, which the immune system learns to recognize as an invader. Biontech struck a development deal with Pfizer in March.

The vaccine comes with complex distribution challenges as it must be shipped and stored at -70C, requiring specialized ultra-cold freezers or supplies of dry ice.

Moderna's vaccine employs the same technology but does not need to be stored at sub-arctic temperatures.