Many parts of the world are again facing the question of whether or not to mask up in public. After saying no in May as vaccinations picked up, the US Centers for Disease Control and Prevention now says yes, wear a mask even if vaccinated, depending on where you live. This reversal may seem confusing and frustrating, but the amended policy actually falls in line with much of the rest of the globe. Host Marco Werman speaks with Ben Cowling, an epidemiologist and a researcher of masks at The University of Hong Kong about the science and politics of masking around the globe right now.