Lee H, et al. - In view of the ongoing rubella epidemic in Japan since August 2018, researchers sought to estimate the likely size of a congenital rubella syndrome (CRS) epidemic during 2018–19 in the present study. They used an integral equation based on age-specific incidence of rubella among adult women, the time delay from gestational age of infection to diagnosis of CRS, and distribution of the mothers’ age at delivery to estimate the expected number of CRS cases. The epidemic data during 2012–14 revealed 45 cases of congenital rubella syndrome in Japan during 2012–14. They estimated the mean time delay of 24 weeks, from mother’s infection to diagnosis. In 2019, there would already be 13.0 cases of CRS to be reported in 2019 given a total of 650 rubella cases in women by week 5 in 2019, and an increase in the expected number of CRS cases is likely given additional rubella cases in adult women.