Johnson & Johnson announced today (January 29) that its one-shot vaccine is 66% effective at preventing moderate and severe COVID-19 and 85% protective against severe disease.

“This is a really great result,” Akiko Iwasaki, an immunologist at Yale University, tells The New York Times. “I hope this vaccine gets approved as soon as possible to reduce disease burden around the world.”

No one who received the shot died of COVID-19, while five individuals in the placebo group did, Reuters reports. “The key is not only overall efficacy but specifically efficacy against severe disease, hospitalization, and death,” Walid Gellad, a physician who studies health policy at the University of Pittsburgh, tells Reuters.

Although the company’s vaccine is less effective at preventing COVID-19 than Moderna’s and Pfizer’s versions are, it still surpasses the US Food and Drug Administration’s 50% efficacy requirement for emergency use approval. Unlike rival vaccines that are administered as two doses, Johnson’s and Johnson’s vaccine requires just a single injection.

The one-shot vaccine could be a “game changer,” Jonathan Temte, a vaccine expert at the University of Wisconsin School of Medicine and Public Health, tells The Washington Post, because it could simplify vaccine distribution. In addition, Johnson & Johnson’s vaccine doesn’t need to be stored in temperatures as cold as Moderna and Pfizer’s versions.

Interim results from the Phase 3 trial—which involved more than 40,000 participants in eight countries—found that vaccine performance varied across the world. In the US, it protected against moderate or severe COVID-19 72% of the time, but just 57% of the time in South Africa, where a worrying new variant of the virus—B.1.351—first emerged. Against severe COVID-19, the vaccine retained its 85% effectiveness against all variants tested, including B.1.351.

The vaccine “will potentially protect hundreds of millions of people from serious and fatal outcomes of COVID-19. It also offers the hope of helping ease the huge burden placed on healthcare systems and communities,” says Paul Stoffels, Johnson & Johnson’s vice chairman of the executive committee and chief scientific officer, in the announcement.

Johnson & Johnson’s vaccine uses deactivated common cold viruses to deliver SARS-CoV-2 DNA, whereas Pfizer’s and Moderna’s vaccines both use messenger RNA technology. The company says it will apply to the US Food and Drug Administration for an emergency use authorization in early February and have doses ready to ship immediately.