Serum Institute of India, which makes the most used Covid-19 vaccine in the country, on Saturday defended pricing Covishield vaccine at 1.5 times the initial rate, saying the earlier price was based on advance funding and now it has to invest in scaling up and expanding capacity to produce more shots.

Serum Institute of India (SII), which manufactures AstraZeneca's vaccine Covishield at its Pune facility, earlier this week announced a price of Rs 600 per dose and at Rs 400 for state governments and any new contract by the central government.