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.
Hamas decided not to respond or engage with Israel's counter-proposal for a ceasefire in Gaza, an official told Reuters on Wednesday, affirming it is committed to the mediators' plan instead.
Israel launched airstrikes on military airbases and infrastructure sites in the Syrian cities of Damascus, Hama and Homs on Wednesday, the Israeli military said.
The White House has confirmed that tech billionaire Elon Musk will stay on to complete his mission to slash government spending and downsize the federal workforce, dismissing media reports that he will leave the role soon.
At least one person was killed and 10 injured, including three children, in overnight drone attacks by Russia on Ukraine, officials said on Wednesday. Various attacks also damaged energy facilities in two regions, according to the Ukrainian president Volodymyr Zelenskyy.
Israel announced a major expansion of military operations in Gaza on Wednesday, saying large areas of the enclave would be seized and added to its security zones, accompanied by large-scale evacuation of population.