New Delhi, May 29 -- Industry, academia and start-ups in India are working on at least 30 vaccine candidates, principal scientific adviser K VijayRaghavan said on Thursday, adding that 20 of them are progressing at a good pace.

The focus is on four kinds of vaccine platforms, he said. First is an mRNA vaccine that uses a component of the genetic material of the virus and translates it into a viral protein within an individual's body to produce an immune response. Second, a weakened form of the virus is injected into a patient that does not cause the disease but produces immune response. Third, the genetic material of the virus is encoded in another viral backbone and injected to produce an immune response. And fourth uses a viral protein d...