While two billion doses of Covid-19 vaccines by the end of this year may be difficult, industry and analysts say a significant portion of the adult population can be covered with at least one dose by December. The ambitious ramp-up plans, however, depend on the availability of raw material, the ability to scale up manufacturing drug substances, and forging partnerships to use the “fill-and-finish” capacities to their fullest. The world’s largest vaccine maker by volumes — Serum Institute of India (SII) — is making 70 million doses a month of Covishield and has started stockpiling Novavax vaccines too. In the July quarter, SII will scale up this capacity to make 100 million doses a month of Covishield. Assuming 100 million doses a month from August, SII will be able to supply 500 million doses between August and December.