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.
President Donald Trump could meet Russian leader Vladimir Putin as soon as next week, a White House official said, as the US continued preparations to impose secondary sanctions, including potentially on China, to pressure Moscow to end the war in Ukraine.
Ghana's Defence Minister Edward Omane Boamah died in a military helicopter crash on Wednesday along with four other officials and three airforce crew, the government said.
Israel's military chief has pushed back against Benjamin Netanyahu's plans to seize areas of Gaza it doesn't already control, three Israeli officials said, as the prime minister faces increasing pressure over the war both at home and abroad.
Hezbollah said on Wednesday the Lebanese government was committing a "grave sin" by tasking the army with establishing a state monopoly on arms, sharpening a national divide over calls for the Shi'ite Muslim group to disarm.
US envoy Steve Witkoff held talks with Russian President Vladimir Putin in the Kremlin on Wednesday, two days before the expiry of a deadline set by President Donald Trump for Russia to agree to peace in Ukraine or face new sanctions.