US lawmakers and non-profit groups on Friday heaped pressure on the Biden administration to back a temporary patent waiver for Covid-19 vaccines to help poor countries contain the pandemic.

The groups delivered a petition signed by two million people, adding to separate letters already sent to US President Joe Biden by a group of senators, House of Representatives Speaker Nancy Pelosi, nearly 100 members of the House and 60 former heads of state and 100 Nobel Prize winners...