The U.S. Food and Drug Administration (FDA) issued new guidance Tuesday for Operation Warp Speed, the Trump administration’s expedited push to develop a viable coronavirus vaccine by year’s end.

FDA Commissioner Stephen Hahn and Health and Human Services Secretary Alex Azar previously outlined how Warp Speed is bypassing the usual clinical trial structure to rush a vaccine to market, but Tuesday’s guidance makes it clear that vaccine candidates will only be deemed successful if they prove to be 50% more effective than a placebo in preventing the disease.

Vice President Mike Pence told reporters at a briefing Friday, the first public coronavirus task force briefing in two months, that the administration believes that multiple vaccine candidates are capable of hitting that efficacy benchmark. (RELATED: Trump Administration Transitioning To ‘More Sustainable’ Federal Testing Strategy, To Be Completed By June 30)

The text also notes that the current initiative will be terminated 60 days after the president ends the declared state of emergency on coronavirus.

The Wall Street Journal estimated Tuesday that the FDA’s new guidance will require clinical trials of at least 30,000 patients to be deemed successful.

Trump has repeatedly stated his goal of producing between 200 and 300 million doses of a viable vaccine by the end of the year, and Hahn and Azar previously told the Daily Caller “that is a goal that would be unprecedented and historic.”

The pair also explained that expediting preliminary efficacy tests will allow mass production and final stage clinical trials to occur simultaneously, with the successful candidates immediately being put into circulation.