Bharat Biotech's vaccine, whose emergency use approval before finishing final stage testing had triggered a row, has shown an 81 per cent efficacy in preventing symptomatic COVID-19 in an interim analysis of the advanced clinical trial, the company said on Wednesday, boosting prospects of its usage. In a statement, Bharat Biotech Chairman Krishna Ella said Covaxin has "demonstrated high clinical efficacy" as also shown "significant immunogenicity" against rapidly emerging variants. The drug regulator in January had allowed Covaxin as well as the vaccine made by AstraZeneca's local partner, the Serum Institute of India Ltd. Watch the full video for more details.