How does the Moderna Covid-19 vaccine work?

US firm Moderna said the trial results indicate the jab is generally well tolerated with no serious safety concerns

(Moderna/PA)

President Donald Trump has said a coronavirus vaccine made by Moderna has been approved for use in the US and distribution will start immediately.

It comes after a panel of US Food and Drug Administration (FDA) advisers said the benefits of the vaccine outweighed the risks for those aged 18 and up.