Bharat Biotech's coronavirus vaccine, which is still undergoing clinical trial, is likely to be the "back-up" vaccine in the coming days, Dr Randeep Guleria, the chief of Delhi's All-India Institute of Medical Sciences said today as two vaccines got emergency approval from the country's drug regulator. Politics has started over the approval to Covaxin, with several opposition parties pointing out that the vaccine was approved without the full process.