Omicron is a new coronavirus variant of concern. Understanding how serious it may or may not be will take some time. But many countries, especially in the West, have been swift to impose travel bans on countries in southern Africa, where scientists first detected the variant just last week. It might seem intuitive to limit travel to curb the spread of the new variant. But, as The World’s Elana Gordon reports, researchers have found that these kinds of standalone bans may do more harm than good.