The first coronavirus vaccine to be tested in people appears to be safe and able to stimulate an immune response against the infection, the manufacturer, Moderna, announced Monday, offering a glint of hope to a world desperate for ways to stop the pandemic.

The preliminary findings, in the first eight people who each received two doses of the experimental vaccine, must now be repeated in far larger tests in hundreds and then thousands of people, to find out if the vaccine can work in the real world. Moderna’s technology, involving genetic material from the virus called mRNA, is relatively new and has yet to produce an approved vaccine.

The promising early news sent Moderna’s stock soaring by more than 25 percent on Monday afternoon and helped drive Wall Street to its best day in six weeks. Stocks were also lifted by statements from the Federal Reserve chair, Jerome H. Powell, that the central bank would continue to support the economy and markets.

Dozens of companies and universities are rushing to create coronavirus vaccines, and human trials have already started for several manufacturers, including Pfizer and its German partner BioNTech, the Chinese company CanSino and the University of Oxford, which is working with AstraZeneca.

Experts agree that it is essential to develop multiple vaccines because the urgent global need for billions of doses will far outstrip the production capacity of any one manufacturer. But there is widespread concern among scientists that haste could compromise the safety, resulting in a vaccine that does not work or even harms patients.

The potential strength of Moderna’s mRNA approach to vaccine making is that it uses a genetic framework that can be quickly adapted for each new viral threat. The company has said that it is proceeding on an accelerated timetable, with the second phase of tests involving 600 people to begin soon, and a third phase to begin in July involving thousands of healthy people. The Food and Drug Administration gave Moderna the go-ahead this month for the second phase.

If those trials go well, some doses of a vaccine could become available for widespread use by the end of this year or early 2021, Dr Tal Zaks, Moderna’s chief medical officer, said in an interview. “We’re doing our best to make it as many millions as possible.”