(NEW BRUNSWICK, N.J.) — As the race for a safe and effective coronavirus vaccine continues, one manufacturer has announced a major step in the right direction.

American pharmaceutical company Johnson & Johnson said Wednesday it will be starting Phase 3 clinical trials, joining Moderna, Pfizer and AstraZeneca to become the fourth manufacturer affiliated with the U.S. government’s Operation Warp Speed.

Phase 3 clinical trials mark an important sign of progress, as the trial is expanded to tens of thousands of volunteers and is generally the last phase before a product reaches the general public.

“Four COVID-19 vaccine candidates are in Phase 3 clinical testing in the United States just over eight months after SARS-CoV-2 was identified,” Dr. Anthony Fauci said in a statement.

“This is an unprecedented feat for the scientific community made possible by decades of progress in vaccine technology and a coordinated, strategic approach across government, industry and academia,” he said.

The trial, which will be funded jointly by the company and the U.S. government, will enroll over 60,000 participants in 215 locations across the U.S. and worldwide. This will make it the largest Phase 3 trial out of the four active vaccine candidates under Operation Warp Speed.

Johnson & Johnson also aims to accomplish several firsts in the vaccine arms race.

Its vaccine will be the first to require a single dose while its competitors use two doses to achieve the expected degree of immunity. Its storage requirements are also better-suited for an average doctor’s office or clinic, compared to Pfizer’s vaccine which needs deep-freeze storage.

“It is likely that multiple COVID-19 vaccine regimens will be required to meet the global need,” Fauci said. “The Janssen [Johnson and Johnson’s parent company] candidate has showed promise in early-stage testing and may be especially useful in controlling the pandemic if shown to be protective after a single dose.”

This vaccine uses an “adenovirus vector” — a modified copy of a common cold virus to induce immunity to COVID-19.

Dave Harrison, M.D., is a pediatric cardiology fellow in Boston and a contributor to the ABC News Medical Unit.

Copyright © 2020, ABC Audio. All rights reserved.