Preliminary results of Phase 1 clinical trials show that Bharat Biotech-ICMR's coronavirus vaccine 'Covaxin' is safe to use, principal investigators conducting the trials told ET. "The vaccine is safe. We have not observed any adverse events in any of the volunteers at our site," Savita Verma, principal investigator, who is leading the trial at PGI Rohtak, said.

Covaxin is being tested on 375 volunteers who have enrolled at 12 sites in India. Two doses of the vaccine are being administered to each volunteer.

"As of now we know that it is safe. The second step is to know how effective the vaccine is for which we have started collecting the samples," Verma said. It is expected that the Phase I will come to a finish by August end.