Drugmakers made big promises for a quick turnaround on coronavirus vaccines. The moment of truth for the front-runners is coming as soon as this month.

The first results showing whether a vaccine can stop people from getting the virus could come by mid-September from AstraZeneca PLC, according to Airfinity Ltd., an analytics company that tracks drug trials. The drugmaker has pledged as many as 30 million doses to the U.K. by the end of the month.

Two other contenders — the U.S.’s Moderna Inc. and the U.S.-German partnership of Pfizer Inc. and BioNTech SE — may also have initial data before a key Food and Drug Administration meeting on virus vaccines scheduled for Oct. 22, Airfinity said. A fourth, China’s Sinovac Biotech Ltd., could have preliminary results shortly after the meeting.