The US Food and Drug Administration on Monday gave full approval to the COVID-19 vaccine made by Pfizer and German partner BioNTech for use in people over the age of 16.
It's the first such approval of a COVID-19 shot.
The vaccine has been authorised for emergency use since December and more than 204 million people in the United States have received it, based on Sunday's data.
But none of the three authorised COVID-19 vaccines had previously received full FDA approval.
Public health officials hope it will convince more unvaccinated Americans that Pfizer's shot is safe and effective.
Vaccine hesitancy among some Americans has hindered the United States response to the novel coronavirus.
"While millions of people have already safely received COVID-19 vaccines, we recognize that for some, the FDA approval of a vaccine may now instill additional confidence to get vaccinated," said Janet Woodcock, the US Food and Drug Administration's acting commissioner.
Roughly 51 per cent of Americans have been fully vaccinated so far, even as a recent surge of infections spurred by the contagious Delta variant ravages parts of the country with low vaccination rates.
Prince Harry said on Friday that he wanted reconciliation with the British royal family but his father King Charles will not speak to him over a row over his security and he did not know how long the monarch, who has cancer, would live.
A magnitude 7.4 earthquake struck Drake Passage between Cape Horn and Antarctica at a depth of 10 km (6 miles) on Friday, the United States Geological Survey said.
A ship with humanitarian aid and activists for Gaza was bombed by drones while in international waters off Malta early on Friday, its organisers said, and the Maltese government said after a rescue operation that everyone on board was safe.
A power outage hit several regions of Indonesia's resort island of Bali on Friday and efforts were underway to restore services to those affected, state utility Perusahaan Listrik Negara said.
A Russian drone attack late on Thursday set buildings ablaze in Ukraine's southeastern city of Zaporizhzhia, injuring 29 people, regional governor Ivan Fedorov said.