The temporal relationship between RotaTeq immunization and intussusception adverse events in the Vaccine Adverse Event Reporting System (VAERS)

BACKGROUND In August of 2006, the Advisory Committee on Immunization Practices (ACIP) recommended RotaTeq for routine vaccination of US infants. The hypothesis tested in the present study is that rotavirus vaccines are associated with an increased risk of intussusception adverse events (AEs) characterized by an onset in a biologically plausible a priori identified temporal period post-vaccination (days 3 to 7). MATERIAL/METHODS The Vaccine Adverse Event Reporting System (VAERS) updated as of December 28, 2010 was analyzed. RESULTS Following RotaTeq vaccination, a significantly (p<0.001) higher percentage of AEs were classified as serious, permanently disabling, resulted in hospitalizations, or were life-threatening among intussusception AEs in comparison to the total AE reports (removing intussusception AE reports) submitted to VAERS. A significantly greater portion of intussusception AEs in comparison to the portion of total AE reports (removing intussusception AE reports) were reported to VAERS in the onset interval from 3 to 7 days post-RotaTeq vaccination than within the onset interval from 1 to 2 days post-RotaTeq vaccination (78.7% vs. 29.1%, risk ratio=2.7, 95% CI=2.4-3.0, p<0.0001). It was assumed in our onset time-trend analyses of the distribution of AEs following Rota-Teq vaccination that the AE's should be equally likely to be reported with an onset time for each day, from 1 to 9 days post-vaccination or, alternatively, should follow similar daily proportions as observed for total AEs reports (removing intussusception AE reports). Results of this onset time-trend analyses of the distribution of intussusception AEs reported to VAERS following Rota-Teq vaccination revealed significant differences (p<0.001) from our expectations. Consistent and similarly remarkable trends were observed for intussusception AE reports associated with RotaShield vaccine. CONCLUSIONS The present study significantly associates RotaTeq vaccination with intussusception AEs.