Preliminary results from a massive real-world trial involving 600 villages in Bangladesh have affirmed that masks — especially surgical ones — can really help reduce the spread of symptomatic COVID-19 infections. Host Carol Hills speaks with Yale economist Ahmed Mushfik Mobarak — who helped lead the study with the country’s ministry of health — about the findings, how to best encourage people to wear masks and why the research is prompting a major push in mask distribution across South Asia.