Covaxin third phase clinical trials results out, 77.8 per cent effective against Covid-19 Covaxin has also been found to be 65.2 percent effective against the dreaded Delta variant of Coronavirus, which is becoming the dominant strain of the virus across the world. Share Via Email | A+A A- By Express News Service HYDERABAD: Covaxin, the Covid-19 vaccine developed by Hyderabad-based vaccine maker Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR), has been found to be 77.8 percent effective in the Phase-III clinical trials. Also, Covaxin has been found to be 93.4% effective against severe symptomatic form of Covid-19 and 63.6 percent effective against asymptomatic Covid-19.