The world marks the last week of April as World Immunisation Week. The theme this year is ‘Long Life for All’ where the focus is on spreading the message that immunisation is one of the world’s most successful and cost-effective health interventions, and it helps save millions of lives. We talk to Dr Vivek Virendra Singh, Health Specialist Officer in Charge, Chief of Health, UNICEF about India’s immunisation programme, COVID-19 vaccines, booster shots and more.