(Karachi) In a last stage clinical trial, an experimental coronavirus vaccine developed by China's Sinovac Biotech appeared to be safe, preliminary results showed.

Brazil's leading bio-medical research centre Butantan Institute engaged in carrying out the Phase 3 tests, said the two-dose vaccine, called CoronaVac, proved to be safe in a trial so far involving 9,000 volunteers.

But the research institute's director Dimas Covas said that results of the data on vaccine's effectiveness will not be released till completion of the trial. The trial is being conducted on 13,000 volunteers.

He stated that researchers will keep monitoring the participants in the on-going trial. He mentioned there were no severe adverse reactions to the vaccine, with 20% of the volunteers reporting mild pain

It's the first set of results of Sinovac's Phase 3 global trials, which are also being conducted in Turkey and Indonesia.

Earlier, the China-based biopharmaceutical company Sinovac Biotech started Phase III clinical trial of its inactivated Covid-19 vaccine in Turkey. The company has already performed Phase I/II studies of the vaccine in volunteers aged 18 to 59 years and those aged 60 years old and above, at Jiangsu and Hebei Provinces on April 16 and May 22, respectively, in China.