What’s the best scale to use to study the spread of disease? With COVID-19, we’ve seen that it’s not at the scale of a country or even a state — the variation from county to county makes that clear. A new study in Nature Communications shows that we may have to go all the way down to a single city block, and that the key feature is to choose areas with a similar population density.

SFI External Professors Aaron King and Mercedes Pascual and collaborators studied the spread of a new variety of dengue fever over two years in Rio de Janeiro. They analyzed the size of the second peak of transmissions relative to the first. In areas with both particularly high and particularly low densities, the second peak tended to be worse than the first, whereas in areas with intermediate densities, the ratio of the second peak to the first was not as high. Their findings contribute to understanding the fundamental drivers for vector-borne diseases like dengue, as well for other infectious diseases like the seasonal flu and COVID-19.

Read the paper at doi.org/10.1038/s41467-022-28231-w