Covaxin can target mutated coronavirus strains and maybe used us a "backup", as they asked for the scientific basis for the claim and for the vaccine's safety and efficacy.The country's drugs regulator Sunday granted emergency use approval to Oxford-AstraZeneca's Covishield and also to indigenously developed Covaxin even though not enough data on the latter's efficacy and safety was available, which triggered a debate.Also Read | A year on, China is shaking up the worldNoted virologist Shahid Jameel said he does not believe that eventually Covaxin would turn out to be safe and show more than 70 per cent efficacy."I say this based on the platform, which is widely used and Bharat Biotech's own track record of successfully making inactivated.