Phase 3 trial: Covaxin 77.8% effective against symptomatic COVID-19, 65.2% against Delta Variant The vaccine demonstrated 93.4% efficacy against severe symptomatic cases company said. The results are based on the evaluation of 130 confirmed cases. (Image Source: Reuters) Updated: Jul 3, 2021, 11:11 AM IST Hyderabad-based Bharat biotech's Covaxin has been found to be 77.8% effective against symptomatic COVID-19 in its phase 3 clinical trials. It also showed 65.2% efficacy against the Delta Plus variant. The results are based on the evaluation of 130 confirmed cases. The indigenously developed vaccine demonstrated 93.4% efficacy against severe symptomatic COVID-19, the company claimed. The safety analysis demonstrated that adverse events reported post-vaccination were similar for Covaxin and the placebo. Twelve percent of subjects experienced commonly known side effects and less than 0.5% of subjects felt serious adverse events.