Bharat Biotech, the company that manufactures Covaxin, has started trials on Monday for booster dose at AIIMS Patna and Delhi. The study will be conducted in phase two clinical trial participants. The study had begun in April after the vaccine manufacturer got DCGI’s approval for the third Covaxin dose. The booster dose is to be given six months after the participants had received their second dose in the trial, which had taken place between September and October 2020.