The United States Food and Drug Administration has fully approved the Pfizer-BioNTech COVID-19 vaccine.
The move is expected to trigger a new wave of vaccine mandates as the coronavirus Delta variant sweeps the country.
President Joe Biden is endorsing the move and is urging the unvaccinated to go and get their inoculations.
The FDA had previously approved three vaccines - Pfizer, Moderna and Johnson & Johnson - under an emergency use authorisation.
Pfizer is the first to receive full FDA approval, which Mr Biden dubbed the gold standard.
The cumulative total of global COVID-19 cases exceeded 212 million, with the death toll surpassing 4.43 million.
On the day of the Opening Ceremony, International Paralympic Committee President Andrew Parsons has expressed confidence that the Paralympics would be held safely, amid a rise in COVID-19 cases in Japan.
Japan's fifth wave of infections has prompted the government to extend pandemic emergency measures in Tokyo and other regions until the 12th of September.
