Rotavirus vaccination: a risk factor for intussusception?

Recently published pharmacoepidemiological studies associate the currently authorized Rotavirus (RV) vaccines with intussusception (IS). We aimed at investigating whether, in Germany, there are excess IS cases in RV vaccinees compared with the background incidence before market authorization in 2006. Suspected cases of IS following receipt of RV vaccines reported to the Paul-Ehrlich-Institut (PEI) from 2006 to 2010 were reviewed and validated against the criteria of the Brighton Collaboration's definition for IS. An observed-versus-expected analysis was conducted using standardized morbidity ratio (SMR) methods based on age-specific incidence rates for IS ranging from 19.2 to 98.5 per 100,000 person-years. A total of 27 cases of suspected IS in RV vaccinees were reported to the PEI. No excess of IS cases could be detected 1-7 days after receipt of either RV vaccine after any dose in the first year of life; however, in infants aged 3-5 months, a significantly increased SMR for IS was found in a risk window of 1-7 days after the first dose of either RV vaccine [SMRs: Rotarix® 4.6 (95% CI 1.5-10.7); RotaTeq® 5.8 (95% CI 1.2-17.1)]. A significantly increased risk of IS in a risk window of 1-7 days after RV vaccination was not found when the first dose was administered earlier. Therefore, it is recommended to start the vaccination course at 6-12 weeks of age.