United States President Donald Trump approved the Pfizer-BioNTech Covid-19 vaccine on Friday, calling it a “medical miracle”. He added that the first doses of the vaccine will be given to the millions of vulnerable people “in less than 24 hours”.

The US has recorded more than 300,000 confirmed deaths due to the coronavirus pandemic. The world’s worst-affected country by the virus became sixth to approve a two-dose regimen. Britain, Canada, Bahrain, Saudi Arabia and Mexico are among the countries that approved a two-dose regimen earlier.

Earlier in the day, the White House had threatened to fire Food and Drug Administration chief Stephen Hahn for failing to grant an emergency approval on Friday.

As many as 20 million people will be injected with the vaccine this month, with health care workers being on the top of the priority.

“The FDA’s authorization for emergency use of the first COVID-19 vaccine is a significant milestone in battling this devastating pandemic that has affected so many families in the United States and around the world,” FDA Commissioner Hahn said in a statement.

“Today’s action follows an open and transparent review process that included input from independent scientific and public health experts and a thorough evaluation by the agency’s career scientists to ensure this vaccine met FDA’s rigorous, scientific standards for safety, effectiveness, and manufacturing quality needed to support emergency use authorization. The tireless work to develop a new vaccine to prevent this novel, serious, and life-threatening disease in an expedited timeframe after its emergence is a true testament to scientific innovation and public-private collaboration worldwide,” he added.