Last year, after several months of COVID-19 positive cases on the rise, India saw a decline in cases after September, even though lockdown restrictions were lifted, and economic and other activity resumed. From March onwards this year however, there has once again been a steep rise in infections, in what many are terming the country's 'second wave'. Earlier this week, Niti Aayog member V.K. Paul said the whole country was potentially at risk. The number of new cases added on March 1 was 3,000 but has now become nearly nine times that and daily deaths too, have shot up three-fold. What has driven this second wave? What is the role, if any, played by mutant strains of the virus in the surge of infections? Is vaccination taking us towards herd immunity? Guest: Giridhara R. Babu Professor of Epidemiology at the Indian Institute of Public Health, PHFI, Bengaluru. Host: Zubeda Hamid