Pfizer and BioNTech will supply the United States with an additional 100 million doses of their vaccine for the coronavirus disease 2019 (Covid-19) under a second agreement.

The drugmakers said on Wednesday that they expect to deliver all the doses by July 31.

Pfizer already has a contract to supply the government with 100 million doses of its vaccine, which requires two doses per patient.

Under the nearly $2 billion deal announced Wednesday, the companies will deliver at least 70 million additional doses by June 30, with the remaining 30 million to be delivered no later than July 31. The government also has the option to acquire up to an additional 400 million doses.

Health and Human Services Secretary Alex Azar said in a statement that the latest deal can give people confidence “that we will have enough supply to vaccinate every American who wants it by June 2021.”

Pfizer’s vaccine was the first to gain authorization for emergency use from the Food and Drug Administration (FDA), and initial shipments went to states last week. It has now been joined by a vaccine from Moderna, which was developed in closer cooperation with scientists from the National Institutes of Health.

Moderna’s vaccine, which also requires two doses, comes under the umbrella of the government’s own effort, which is called Operation Warp Speed. That public-private endeavor was designed to have millions of vaccine doses ready and available to ship once a shot received FDA approval. SOVEREIGNPH