At a time when India's biggest challenge has become shortage of vaccines to fight the Covid pandemic, comes an important peer-reviewed study that has big policy implications to enable larger vaccine coverage in the population. This study, carried out in Hyderabad and published in the International Journal of Infectious Diseases, says single dose vaccination in previously exposed individuals produces sufficient antibody and immune response. Padma Bhushan Dr Nageshwar Reddy tells NDTV's Uma Sudhir in an exclusive interview that it could become an important and effective strategy for India to vaccinate larger population.