Intussusception and Kawasaki disease after rotavirus vaccination in Taiwanese infants

Background: Since 2006, two rotavirus vaccines have been licensed in Taiwan, either as a 2- (RV1) or 3-dose (RV5) schedule administered at ages 2, 4, and 6 months. This study assessed the risk of intussusception and Kawasaki disease (KD) associated with rotavirus vaccines among infants. Methods: Cases of intussusception and KD in infants aged less than 365 days were identified from the National Health Insurance databases, from 1 January 2007 through 31 December 2014, using the first-ever ICD-9-CM diagnosis codes. Histories of rotavirus vaccination were obtained from the National Immunization Information System. The modified self-controlled case series design included vaccinated cases, and compared incidence rate ratios (IRRs) between the risk period (postvaccination days 1–21 [intussusception] or days 1–28 [KD]) and control period (ages 0–364 days outside the ?14 to +21 [intussusception] or +28 [KD] days of vaccination) by each type and dose of vaccine. Conditional Poisson regression models were adjusted for age using age-in-week (7-day) categorization. Results: Overall 2064 intussusception cases and 2079 KD cases were diagnosed in 567,726 recipients (5313 [0.9%] received both RV5 and RV1). An increase in intussusception risk was observed in the 1–7 days (IRR 12.59, 95% confidence interval [CI] 8.07–19.66) and 8–21 days (IRR 1.78, 95% CI 1.00–3.16) post dose 1 of RV1, but not RV5. Risk of KD was higher during the third week post dose 2 of RV5 (IRR 2.33, 95% CI 1.35–4.00), and fourth week post dose 1 of RV1 (IRR 1.98, 95% CI 1.16–3.40). Conclusion: Our finding of an increased risk of intussusception associated with RV1 in the first week after dose 1 is consistent with results of previous postlicensure studies. Further research should verify a potentially delayed risk of KD after rotavirus vaccination. ? 2020 Elsevier Ltd