A Parrish Medical Center medical worker holds a vial of the Moderna COVID-19 vaccine on a ride through the vaccination clinic for Port Canaveral workers, workers at local hotels and restaurants, and residents of the Port Canaveral community.

Paul Hennessy | LightRakete | Getty Images

The U.S. government is in negotiations with Moderna to potentially secure additional doses of Covid-19 vaccine to supply the world, according to a trusted person.

The discussions could result in a similar number of cans purchased as a deal announced Wednesday with Pfizer, said the person who refused to be named because the negotiations are not public.

President Joe Biden is expected to announce at the G-7 summit that the US has purchased 500 million doses of the Pfizer BioNTech vaccine to be donated to 92 low-income countries and the African Union through the Covax global alliance next Year to distribute, according to another trusted person. The news was first reported by the Washington Post and the New York Times.

The Pfizer cans will be bought at a charitable price, the person said. The terms of a possible Moderna deal were not immediately clear.