New Brunswick-based Johnson & Johnson has asked U.S. regulators to clear the world’s first single-dose COVID-19 vaccine, an easier-to-use option that could boost scarce supplies.

Preliminary results from a massive study showed J&J’s vaccine was safe and offered strong protection against moderate to severe COVID-19. The vaccine was found to be 66% effective against moderate to severe infection, and provided strong protection against hospitalization and death. 

It didn’t appear quite as strong as two-dose competitors made by Pfizer and Moderna, but the vaccine can also be stored in regular refrigerators. Medical experts say it’s coming just in time.

"This could not come at a better time,” says Dr. Jonathan Reiner, medical analyst. “Cases are dropping rapidly in the United States. The seven-day moving average for new cases is down 54% since its peak in January, now is the time to put the fire out. This is the perfect vaccine for mass vaccination events, where you really don't want to get people back."

Johnson & Johnson filed an application with the Food and Drug Administration on Thursday.

An FDA panel will meet later this month and pore over the results. The company also is studying a two-dose version of its vaccine, but results won’t be available for several more months.

If approved, authorization could come soon thereafter. Once that happens, the company says they're ready to start shipping immediately. They have a plan to deliver more than 100 million doses this spring.

AP wire services helped contribute to this report.