Gastroenteritis hospitalizations over 19 years before and after introduction of rotavirus vaccine in Japan: A nationwide claims database.

BACKGROUND

Rotavirus is a major cause of pediatric gastroenteritis worldwide, leading to severe health outcomes. Rotavirus vaccines (RV) have introduced grobally, in Japan, introduced in 2010 as self-payment and in 2020 as public funding vaccine. This study evaluates the change of gastroenteritis hospitalization and intussusception.

METHODS

The descriptive study utilized JMDC claims database, focusing on 3 million children under 12 years from January 2005 to July 2023. The primary outcome was the incidence of all-cause gastroenteritis and rotavirus enteritis hospitalizations per 1000 person-year, with secondary outcomes including intussusception. Data were extracted using ICD-10 codes, and hospitalization rates were categorized into three periods: pre-vaccine (before October 2011), post-vaccine introduction (November 2011 to September 2020), and post-public funding (from October 2020). Statistical analyses included descriptive epidemiology, and interrupted time series (ITS) design.

RESULTS

The study included 3,085,932 children (51 % male, 49 % female), with a mean age of 4.16 years. The gastroenteritis hospitalization per 1000 person-year under five year old age was 12.0 pre-vaccine period to 4.8 post-public funding period with a 60 % decrease (p < 0.001). Under the same conditions, hospitalization for rotavirus enteritis was 5.8 pre-vaccine period to 2.5 post-public funding period with a 58 % decrease (p < 0.01). ITS analysis showed a further -0.2 % monthly decrease in rotavirus enteritis hospitalizations post-vaccine introduction (p = 0.007). No significant changes were found for intussusception trends before and after RV.

CONCLUSION

In this study, gastroenteritis hospitalizations and rotavirus enteritis hospitalizations in children significant decreased. Intussusception rate were unchanged throughout the study period.