A high incidence of intussusception in Japan as studied in a sentinel hospital over a 25-year period (1978-2002).

The development of second-generation rotavirus vaccines requires knowledge of baseline incidence rates for intussusception in infants prior to vaccine introduction. To obtain such estimates we reviewed clinical records in a hospital that served as the major provider of paediatric beds in a local community in the northern part of Japan. During the 25-year period (1978-2002), there were 91 hospitalizations due to radiologically confirmed intussusception in children <5 years of age, of which 45% were <1 year of age. Assuming that all children with intussusception in the area had been admitted to this hospital, there were an average of 185 and 78 hospitalizations per 100000 person-years for children <1 year old and 5 years old respectively. There was period-to-period variability with no long-term secular trend in the incidence of intussusception. The incidence rate in Japan was among the highest thus far reported, providing further evidence of geographic variability.