U.S. biotechnology company Moderna Inc. said Tuesday it will start a final-stage clinical trial of a potential coronavirus vaccine involving 30,000 participants on July 27.

The development comes as the Massachusetts-based firm's experimental vaccine for COVID-19, the respiratory disease caused by the coronavirus, proved safe and provoked immune responses in all 45 participants in an early-stage test, which was reported in the New England Journal of Medicine.

A view of U.S. biotechnology company Moderna Inc.'s headquarters in Cambridge, Massachusetts, on May 8, 2020.(Getty/Kyodo) 

U.S. pharmaceutical giant Pfizer Inc. also said Monday it would start as soon as later this month a last-stage clinical trial of a possible vaccine jointly developed by German biotech firm BioNTech SE.

The U.S. Food and Drug Administration has granted the two coronavirus vaccine candidates fast-track status designed to speed up its regulatory review process.

Moderna said in the journal its phase one study showed all of the 45 healthy adult volunteers aged 18 to 55 years produced antibodies after they were given two shots of the potential vaccine, 28 days apart across three dose levels.

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While there were no serious side effects, many of the participants reported mild or moderate symptoms such as fatigue, chills and headaches.

Drugmakers around the world have been stepping up efforts to develop coronavirus vaccines as the COVID-19 crisis has shown no signs of abating.

In Japan, British maker AstraZeneca Plc's unit has said it will cooperate with three local peers -- Daiichi Sankyo Co., Meiji Seika Pharma Co. and KM Biologics Co. -- to supply the country with an experimental coronavirus vaccine jointly developed with the University of Oxford.

Medical startup Anges Inc. has started Japan's first clinical trial on humans of a potential vaccine for the coronavirus, and Shionogi & Co. is also developing one.