The first doses of the COVID-19 vaccine produced by pharmaceutical company Pfizer and German biotechnology company BioNTech will begin arriving in the states across the US after its emergency use was approved, paving the way for a mass immunisation programme in the country.
The US Food and Drug Administration gave the coronavirus vaccine a green light on Friday, after a government expert advisory panel concluded the vaccine appeared safe and effective.
"The FDA’s authorisation 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,” said agency Commissioner Dr Stephen M. Hahn.
Hahn said the action followed "an open and transparent review process" that included input from multiple experts and scientists to determine the vaccine met the agency's standards.
Delivery companies UPS and FedEx will begin rolling out three million doses of the vaccine to nearly 150 distribution centres across the country, according to Army General Gustave Perna of Operation Warp Speed, the Trump administration’s vaccine development program.
Shipments to another 425 sites will be made on Tuesday, and 66 more on Wednesday.
US President Donald Trump called the vaccine news a "medical miracle" and one of the "greatest scientific achievements in history" in a video posted to his Twitter account. He said that the first vaccine would be administered within 24 hours.
The US has signed a deal with Pfizer and BioNTech to buy 100 million doses of the vaccine and can acquire up to 500 million additional doses.
The vaccine requires two doses per person, received several weeks apart.
The United Kingdom was the first country to authorise the Pfizer/BioNTech vaccine and began vaccinating elderly people who are at risk for developing a more severe form of the virus earlier this week.
The European Medicines Agency is currently reviewing the vaccine's safety and efficacy and is set to give a decision before December 29.
Pfizer and BioNTech were the first companies to release preliminary efficacy results from phase three trials, that determined the candidate vaccine was 95% effective, including 94% effective in adults over the age of 65.
The vaccine, like a coronavirus vaccine developed by Moderna, uses messenger RNA to instruct cells in the body to make the virus' spike protein.
This does not cause the illness but triggers the immune system to make antibodies against the virus.