Tie-up with Serum Institute of India key to mass production of COVID vaccines, say two pharma majors Updated : February 25, 2021 07:44 AM IST Located in the city of Pune in Maharashtra, the SII is the world’s largest vaccine manufacturer by volume. It is manufacturing the coronavirus vaccine developed by AstraZeneca and Oxford University, which is known locally as Covishield. Published : February 25, 2021 07:41 AM IST