Adar Poonawalla became the CEO of the world's largest vaccine manufacturer, Serum Institute of India, when he was 30 years old. | Bloomberg | Getty ImagesAdar Poonawalla became the CEO of the world's largest vaccine manufacturer, Serum Institute of India, when he was 30 years old. Today, it is the world's largest vaccine manufacturer — by number of doses produced and sold globally. In 1966, at the age of 25, the elder Poonawalla embarked on a journey to set up the Serum Institute of India. Vaccine production at the Serum Institute of India pharmaceutical plant in Pune, Maharashtra, India.

---