It was revealed in January that as many as 6 million Covid-19 vaccine shots are left in stock in Malaysia, after expired doses were destroyed due to poor demand. Why is it so tricky to estimate the amount of vaccines needed? Dr Khoo Yoong Khean, Scientific Officer, Duke-NUS Centre for Outbreak Preparedness, talks to us about navigating the balance of ensuring enough stock to tackle any pandemic while ensuring vaccine equity especially for poorer nations.

Image credit: Shutterstock