A federal agency has made a deal that will lead to the eventual delivery of enough doses of an experimental coronavirus vaccine to innoculate every American adult at least once.

The Department of Health and Human Services (HHS) will provide AstraZeneca (NYSE:AZN) up to $1.2 billion to accelerate the development of ChAdOx1 nCoV-19, a gene therapy the British pharmaceutical giant licensed from Oxford University last month. Among other commitments, HHS will support a clinical trial with 30,000 participants to determine whether the vaccine candidate works as hoped.

In return, AstraZeneca has agreed to provide the U.S. with up to 300 million doses, the first of which could ship out before the end of 2020. AstraZeneca has also agreed to provide 100 million doses to people in Great Britain.

Gloved hands pipetting lots of samples.

Image source: Getty Images.

ChAdOx1 nCoV-19 is really a set of genetic blueprints for a recognizable spike protein that occurs on the surface of the coronavirus that causes COVID-19. Those blueprints are delivered by a non-replicating adenovirus, which is an increasingly common technique in the treatment of inherited disorders, but is something new in the world of vaccines.

The Oxford University researchers who developed ChAdOx1 nCoV previously used the same adenovirus to deliver blueprints for the spike protein found on the coronavirus responsible for Middle East respiratory syndrome (MERS). In a small clinical study, ChAdOx1 MERS appeared to prevent transmission of MERS-CoV, which means there's a good chance ChAdOx1 nCoV-19 can effectively prevent further COVID-19 outbreaks.

AstraZeneca licensed Oxford's vaccine on April 30, and the pharmaceutical giant has already secured manufacturing capacity for 1 billion doses. The first deliveries are expected to begin in September if ongoing clinical studies continue pointing in the right direction on its efficacy.