Still reeling from the coronavirus, the U.S. government has opted to double its take-up of Pfizer (NYSE:PFE) and BioNTech's (NASDAQ:BNTX) coronavirus vaccine. Both companies announced Wednesday morning that the federal government has reached an agreement with them to supply an additional 100 million doses of BNT162b2, adding to the original 100 million-dose order.

The feds will pay $1.95 billion for the new order.

Pfizer and BioNTech said that they expect to fill the total order of 200 million doses by July 31, 2021. As for the new part of the order, the companies said that a minimum of 70 million doses will be delivered by the end of June, with the rest to come within the following month.

"This new federal purchase can give Americans even more confidence that we will have enough supply to vaccinate every American who wants it by June 2021," the companies quoted Health and Human Services (HHS) Secretary Alex Azar as saying.

Nevertheless, that might not be the end of the government's commitment. Per the terms of its agreement with Pfizer and BioNTech, it has an option to secure an additional 400 million doses of BNT162b2 should that be deemed necessary.

Earlier this month, the vaccine received Emergency Use Authorization (EUA) from the Food and Drug Administration (FDA). Roll-out has been relatively quick; at the moment, some frontline healthcare workers and high-ranking government officials such as Vice President Mike Pence have received their initial jabs (BNT162b2 is a two-dose vaccine).

While Pfizer's stock was up robustly (by 2.1%) in late-afternoon trading Wednesday, eclipsing the gain of the S&P 500 index, BioNTech shares were down by nearly 0.8%.

This article originally appeared in the Motley Fool.

Eric Volkman has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.

covid-19 vaccine A COVID-19 vaccine is pictured. Photo: AFP / Ricardo ARDUENGO