Intussusception risk after rotavirus vaccination in Korean infants

An increased risk of intussusception after Rotavirus vaccination has been reported, with varying levels of risk associated with Rotarix and RotaTeq. This study evaluates the risk of intussusception following Rotarix and RotaTeq vaccination in Korean infants.

We performed a self-controlled case series study using vaccination registry from the Korea Disease Control and Prevention Agency and the National Health Insurance Service claims data. This study included infants aged less than one year who received at least one dose of Rotarix or RotaTeq within 8 months of birth between June 1, 2016, and December 31, 2022. An intussusception event was defined as the first hospitalization for intussusception. We defined the risk intervals as 1-7 days, 8-21 days, and 1-21 days post-vaccination and the observation period as from birth to one year. Conditional Poisson regression model was used to estimate the adjusted incidence rate ratio (aIRR) with adjustments for age effects by the monthly interval. The attributable risk was calculated using aIRR estimates and the estimated number of vaccine doses administered to the infants. Pseudo-likelihood methods accounted for the potential contraindication to vaccination after intussusception.

Among 786,977 infants receiving Rotarix, 764 intussusception cases occurred, while 751 cases were identified among 800,232 infants who received RotaTeq. For Rotarix, the IRR during the 1-7 day risk intervals after the first dose was 3.15 (95 % confidence interval [CI] 1.54-6.44) with an attributable risk of 2.17 (95 % CI 1.11-2.68) per 100,000 doses and an absolute risk of 3.18 per 100,000 doses. No significant increase in intussusception risk was observed for RotaTeq across all risk intervals.

The risk of intussusception increased within 7 days after the first dose of Rotarix vaccination, while no significant evidence of an increased risk was observed after RotaTeq vaccination.