A new coronavirus variant - B.1.1.529 - has been flagged by scientists over an alarmingly high number of spike mutations that might make the virus more resistant to vaccines, increase transmissibility and lead to more severe symptoms. On Thursday, the Union Health Ministry called for rigorous screening of passengers from South Africa, Botswana, and Hong Kong, as well as their contacts. We speak to leading medical experts on how dangerous the new variant is and whether it is time for India to roll out booster shots.