Beijing is continuing its mass COVID-19 vaccination drive. It now includes seniors above 60 years of age, based on their health condition, and it's all voluntary. The city has so far administered 10 million doses. Professor Wu Zhiwei, director of Center for Public Health Research at Medical School of Nanjing University, shares his insights about it. He says that China has essentially brought disease under control, while most of the West failed in implementing stern containment measures.