U.S. authorities have been all over the map when it comes to whether ordinary people should wear masks in the era of the coronavirus. At the start of the pandemic in early 2020, the Centers for Disease Control and Prevention discouraged it in most circumstances, in part to preserve supplies for health workers, before changing its position only in April of that year. One of President Joe Biden’s first acts in office was to break with his predecessor by issuing a nationwide, if limited, mask mandate. Biden asked people to mask up until at least the end of April. In May, U.S. health authorities significantly relaxed their recommendations for fully vaccinated people, going beyond easings announced just weeks earlier.