When the outbreak started in Mexico in March, it quickly reached faraway places like China, but took longer to appear in nearby countries such as Barbados. The reason? If we define ‘near’ and ‘far’ in terms of locations on a map, we’re using the wrong notion of distance. Infections are spread by people, and there are more major flight routes linking Mexico and China – such as those via London – than those connecting Mexico with places like Barbados.
