Using long-term data on enteroviruses, researchers have developed a model that can accurately predict the transmission dynamics of various strains and types of viruses. The results could be harnessed to deliver vaccination programs at ideal times, maximizing these programs' efficacy. More than 100 enterovirus serotypes infect humans, causing a wide range of diseases including meningitis, encephalitis, paralysis, upper respiratory infections, hand-foot-and-mouth disease (HFMD), and more. Here, Margarita Pons-Salort and Nicholas Grassly analyzed long-term surveillance data on enteroviruses collected between 2000 and 2015 in Japan, one of the few countries in the world with detailed data on various enterovirus strains and types. The authors observed patterns, where for example a strain of Coxsackievirus switched from a 1-year cycle between 2000 and 2004 to a 2-year cycle from 2004 onward - a pattern that Pons-Salort and Grassly suspected may be due to the general decrease in births that Japan has experienced over recent years. Using the data, the researchers developed a single model that reflected the transmission dynamics of 18 out of 20 of viruses with great accuracy. In a related Perspective, Birgit Nikolay and Simon Cauchemez write, "The analysis indicates that predicting outbreaks for a specific enterovirus serotype may be possible without having to account for cross-protection conferred by other circulating serotypes. In the future, models could be used to anticipate when the next enterovirus outbreak might occur, how large it will be, and which serotype might cause it."