Some sources simply equate the two. On the other hand, Covishield seems to be undergoing its own clinical trials. The statement by the Indian authorities calls it “Recombinant Chimpanzee Adenovirus vector vaccine (Covishield) encoding the SARS-CoV-2 Spike (S) glycoprotein with technology transfer from AstraZeneca/Oxford University” and refers to overseas clinical studies totaling 23 745 participants, presumably AZD1222 phase III clinical trials.

This all is very confusing. Are the two biologically equivalent substances produced by different factories, or different vaccines using the same core ideas?


1 Answer 1


The India-produced Covishield vaccine and the AstraZeneca COVID-19 Vaccine (codenamed AZD1222) are intended to be identical. Covishield is manufactured by Serum Institute of India under license from AstraZeneca, in the same manner as manufacturing of AZD1222 has been licensed to companies in Thailand and South Korea.1 The agreements include transfer of the recombinant chimpanzee adenovirus seed culture (which Oxford and AstraZeneca developed), but also the manufacturing and quality assurance procedures need for reliable production.2 AstraZeneca is also partnering with companies in at least a dozen other countries to manufacture the vaccine in a distributed manner to quickly increase the available supply.2, 3

The Indian Council of Medical Research is funding clinical trials by Serum Institute of India of blinded clinical trials to determine the safety and efficacy of the Serum Intitute-manufactured vaccine (Covishield) in the Indian population versus AstraZeneca-supplied vaccine doses and against placebos.4 Export of Covishield is limited to non-first-world countries and so far has been exported only to nearby countries such as Bangladesh.5

  • Canada also ordered some Covishield, and its regulatory decision states, “The results of this evaluation determined that the two products were sufficiently similar that the efficacy, immunogenicity and safety of COVISHIELD could be inferred from the non-clinical and clinical studies from the AstraZeneca vaccine”. Mar 9, 2021 at 13:32

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