The Pfizer / BioNTech vaccine was urgently authorized in the United States, a first in the country, the most affected by the Covid-19 pandemic.

Donald Trump also indicated the first doses would be inoculated during the day of Saturday, with a prioritization of the elderly, caregivers and first aid.

The United States granted emergency authorization for the Pfizer / BioNTech alliance vaccine against Covid-19 on Friday, the scientific director of the United States Medicines Agency (FDA) announced.

A huge logistics operation was immediately launched to distribute the vaccine to the four corners of the country.

"The first vaccine will be administered in less than 24 hours," Donald Trump said in a video posted on Twitter.

"We have already started sending the vaccine to all states," the US president also said.

Three million doses

It is the first vaccine authorized in the United States, the country most affected by the pandemic, less than eight months after the first injection in a volunteer as part of clinical trials.

In the immediate term, approximately three million doses will be shipped by Pfizer directly to hospitals, pharmacies and designated sites by individual states and some major cities.

The federal government has decided to reserve another three million available doses to send them three weeks later, when the vaccine booster is due to be injected.

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"Governors decide where vaccines should go in their states and who will get them first," said Donald Trump.

"We want our older citizens, caregivers and first aid to be the first." 

Recommendations followed?

The Centers for Disease Prevention and Control (CDC) had recommended that residents of retirement homes (3 million people) and professionals in the health sector (21 million) be given priority.

Most states should adhere to these recommendations.

Never before has the FDA given the green light to a new vaccine so quickly, just three weeks after companies filed their request.

The vaccine, of which the US government has pre-purchased 100 million doses, is 95% effective, which means that it reduces the chances of contracting Covid-19 by the same amount.