HealthGlobal issuesAsk Derrick: Do mask mandates work?To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 videoHealthGlobal issues09/07/2021September 7, 2021Our science correspondent Derrick Williams tackles the issue of mask mandates, which are proving divisive in some places. Do they work or not? What does the science say?https://p.dw.com/p/401qbAdvertisement