India's COVID-19 vaccination programme will start on January 16,in the largest inoculation drive against coronavirus in the world. In the initial phase, the government will pay for the vaccines for three crore healthcare and frontline workers. The plan is to vaccinate 30 crore people by peak summer. Currently, India has two vaccines – Covaxin made by Bharat Biotech, and Covishield produced by the Serum Institute of India. Professor K Srinath Reddy, president of Public Health Foundation, answers frequently asked questions. Do people who have antibodies need to be vaccinated? Why has the vaccination programme in the US and Europe moved slowly, and is India better placed after two dry runs?