Impact after the Change from Voluntary to Universal Oral Rotavirus Vaccination on Consecutive Emergency Department Visits for Acute Gastroenteritis among Children in Kobe City, Japan (2016-2022).

Rotavirus (RV) is the leading cause of acute gastroenteritis (AGE), particularly in infants. In 2006, the high efficacy of oral RV vaccines (RVVs, Rotarix TM and RotaTeq TM ) was demonstrated. Voluntary RVV started in Japan in 2011, and in October 2020 were launched as universal oral RVVs in Japan. However, the impact of changes from voluntary to universal RVVs has not been studied in a primary emergency medical center in Japan. We investigated changes in the number of pediatric patients with AGE after introducing universal RVVs in our center. A clinical database of consecutive patients aged <16 who presented to Kobe Children's Primary Emergency Medical Center between 1 April 2016 and 30 June 2022 was reviewed. After implementing universal RVVs, fewer children presented with RV-associated AGE (the reduction of proportion of the patients in 2022 was -61.7% (all ages), -57.9% (<1 years), -67.8% (1-<3 years), and -61.4% (3-<5 years) compared to 2019). A similar decrease in those of age who were not covered by the universal RVV was observed. There was a significant decline in the number of patients with AGE during the RV season who presented to the emergency department after implementing universal RVVs.