Two drug companies that are leading the race to develop coronavirus vaccines bowed to public pressure on Thursday, abandoning their traditional secrecy and releasing comprehensive road maps of how they are evaluating their vaccines.
The companies, Moderna and Pfizer, revealed details about how participants are being selected and monitored, the conditions under which the trials could be stopped early if there were problems, and the evidence researchers will use to determine whether people who got the vaccines were protected from Covid-19.
Moderna’s study will involve 30,000 participants, and Pfizer’s 44,000.
Companies typically share these documents after their studies are complete. The disclosures while the trials are still underway, a rare move, are aimed at addressing growing suspicion among Americans that President Trump’s drive to produce a vaccine before the election on Nov. 3 could result in a product that was unsafe.
The plan released by Moderna on Thursday morning included a likely timetable that could reach into next year for determining whether its vaccine works. It does not jibe with the president’s optimistic predictions of a vaccine widely available to the public in October.
Pfizer’s plan does not appear to estimate when its results could be available. Its chief executive has said repeatedly that the company hopes to have an answer as early as October. Moderna has said only that it could have a result before the end of the year.
Moderna’s 135-page plan, or protocol, indicated that the company’s first analysis of early trial data might not be conducted until late December, though company officials now say they expect the initial analysis in November. In any case, there may not be enough information then to determine whether the vaccine works, and the final analysis might not take place until months later, heading into the spring of next year.
Moderna’s timeline meshes with the cautionary estimates from many researchers, including Dr. Robert R. Redfield, the director of the Centers for Disease Control and Prevention, who told senators on Wednesday that a vaccine would not be widely available until the middle of next year. Hours later, Mr. Trump sharply contradicted him, making unsubstantiated projections that a vaccine could become widely available weeks from now.
On Wednesday, Joseph R. Biden Jr., the Democratic presidential nominee, said in Wilmington, Del., that the process used to evaluate and approve a vaccine would have to be “totally transparent” to win public confidence. He has said that Mr. Trump’s calls for companies and regulators to speed the process have shaken the public’s faith in vaccines and that politics has no place in vaccine development.
Researchers in particular have been urging vaccine makers to share the detailed blueprints of their studies so that outside experts can evaluate them. At least one expert, after reading the plans, has already raised questions about the way the trials were designed.