From Bharat Biotech Covaxin, AstraZeneca/Oxford/ Serum Institute' Covishield and much more: EXPLAINED
Bharat Biotech's Covaxin is an exception as it is still in Phase-3 and yet to complete trial recruitment. No interim analysis of efficacy is available and pre-print Phase-1/2 data have only given details on immunogenicity and not efficacy of the vaccine. The emergency use approval, even as a back-up vaccine, is therefore highly unusual. Government authorities have announced that Serum's Covishield will remain the primary vaccine for the time being and Bharat Biotech's Covaxin will be in back-up, only to be used in case of a surge in case.
Serum Institute may need to offer better discounts to be able to sign high-quantity contracts with GOI, which are still in the pipeline, or be content with shorter-term contracts until alternatives emerge: Reuters