What happened

Shares of Moderna (NASDAQ:MRNA) were rising 3.1% as of 12:51 p.m. ET. The gain came after results were announced for a COVID-19 vaccine study led by the University of Oxford.

This study found that a second dose of Moderna's vaccine following a first dose of either the Pfizer-BioNTech vaccine or the AstraZeneca vaccine was more effective than two doses of the two other vaccines.

A healthcare professional giving a shot to a person.

Image source: Getty Images.

So what

The University of Oxford study results aren't likely to benefit Moderna all that much in countries that have already vaccinated much of their populations. The U.S. has fully vaccinated around 60% of its population. Close to 66% of people in the European Union have been fully vaccinated.

However, the data could work more to Moderna's advantage in countries that are earlier in their vaccination efforts. It's possible that some of these countries could encourage individuals to use Moderna's Spikevax vaccine as their second dose after receiving a first dose of the AstraZeneca vaccine or the Pfizer-BioNTech vaccine.

There's also a chance that the latest news could sway some in the U.S. and other countries that allow mix-and-match boosters to select Moderna's vaccine. The University of Oxford study didn't evaluate third booster doses, but its results could bolster the perception that Moderna's vaccine offers higher efficacy.

Now what

While Moderna's shares rose modestly today, the most important catalysts for the vaccine stock are potential supply agreements that extend into 2023 and beyond. The main question for Moderna right now is how strong the demand for its COVID-19 vaccine will be over the long term.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.