Children with a previous enterovirus infection have an increased risk of developing type 1 diabetes mellitus (T1DM), show the results of a nationwide cohort study. The researchers used Taiwan's National Health Insurance Research Database to identify children who had an enterovirus infection in 2000–2007, who were matched by sex and birth year with a random sample of children who had not had an enterovirus infection. After exclusion of children with prior T1DM, the incidence of T1DM was compared between the two groups (n = 570,133 for each group) and was found to be significantly higher among the children with a previous enterovirus infection (HR 1.48, 95% CI 1.19–1.83). The authors suggest that preventive approaches such as vaccination could decrease the incidence of T1DM in Taiwan.