The world's biggest COVID-19 vaccine test got underway Monday with the first of 30,000 planned volunteers.

The experimental vaccine is made by the National Institutes of Health and Moderna Inc. It's one of several candidates in the final stretch of the global vaccine race.

Officials are seeking to find out whether more people who get dummy shots become infected than those given two doses of the real vaccine.

The U.S. government plans separate huge studies of several leading vaccine candidates through fall, each in hot spots where the virus still is spreading.

Dr. Anthony Fauci and other Trump administration officials have said that the company is already producing millions of doses of the vaccine in the event that it receives Emergency Use Authorization from the FDA following the trial. Fauci remains cautiously optimistic that a vaccine could be available by January of next year — though it's unclear how long it would take for a vaccine to be available for all Americans who want it.