Scientists and investors were celebrating Monday after drug maker Pfizer announced positive early results from a COVID-19 vaccine.

The news broke after a weekend in which the U.S. media declared Joe Biden the next U.S. president. Biden assembled a coronavirus task force as his first order of business. But President Trump, who has yet to concede defeat, was also celebrating the breakthrough. Biden tempered his reaction.

CGTN’s Owen Fairclough reports.