The US government has agreed to pay $1.95 billion to secure 100 million doses of a potential coronavirus vaccine being developed by US pharma giant Pfizer and Germany's Biontech, according to AFP.

The US also has an option to purchase “an additional 500 million doses”, Biontech said in a statement.

“Americans will receive the vaccine for free consistent with US government's commitment for free access for Covid-19 vaccines,” it added.