Post-Marketing Benefit–Risk Assessment of Rotavirus Vaccination in Japan: A Simulation and Modelling Analysis

INTRODUCTION Rotarix™, GSK's live attenuated rotavirus vaccine, was introduced in Japan in 2011. A recent trend in reduction of rotavirus gastroenteritis (RVGE) due to this vaccine was described. However, an observed/expected analysis showed a temporal association with intussusception within 7 days post dose 1. OBJECTIVE In this paper, we compare the benefit and risk of vaccination side-by-side in a benefit-risk analysis. METHODS The number of vaccine-preventable RVGE-associated hospitalizations and deaths (benefit) and intussusception-associated hospitalizations and deaths (risk) following two doses of Rotarix™ in Japan was compared using simulations. Source data included peer-reviewed clinical and epidemiological publications, Japanese governmental statistics (Statistics Bureau, Ministry of Internal Affairs and Communications), and market survey data. RESULTS For a birth cohort of 1 million vaccinated Japanese children followed for 5 years, the benefit-risk analysis suggested that the vaccine would prevent ~17,900 hospitalizations and ~6.3 deaths associated with RVGE. At the same time, vaccination would be associated with about ~50 intussusception hospitalizations and ~0.017 intussusception deaths. Therefore, for every intussusception hospitalization caused by vaccination and for one intussusception-associated death, 350 (95 % CI 69-2510) RVGE-associated hospitalizations and 366 (95 % CI 59-3271) RVGE-associated deaths are prevented, respectively, by vaccination. CONCLUSIONS The benefit-risk balance for Rotarix™ is favorable in Japan. From a public health perspective, the benefits in terms of prevented RVGE hospitalizations and deaths for the vaccinated population far exceed the estimated risks due to intussusception.