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Background Rotavirus is a major cause of severe gastroenteritis in children worldwide. The disease burden has been substantially reduced in countries where rotavirus vaccines are used. Given the risk of vaccine-induced intussusception, the benefit–risk balance of rotavirus vaccination has been assessed in several countries, however mostly without considering indirect protection effects. Aim We performed a benefit–risk analysis of rotavirus vaccination accounting for indirect protection in France among the 2018 population of children under the age of 5 years. Methods To incorporate indirect protection effects in the benefit formula, we adopted a pseudo-vaccine approach involving mathematical approximation and used a simulation design to provide uncertainty intervals. We derived background incidence distributions from quasi-exhaustive health claim data. We examined different coverage levels and assumptions regarding the waning effects and intussusception case fatality rate. Results With the current vaccination coverage of < 10%, the indirect effectiveness was estimated at 6.4% (+/− 0.4). For each hospitalisation for intussusception, 277.0 (95% uncertainty interval: (165.0–462.1)) hospitalisations for rotavirus gastroenteritis were prevented. Should 90% of infants be vaccinated, indirect effectiveness would reach 57.9% (+/− 3.7) and the benefit–risk ratio would be 192.4 (95% uncertainty interval: 116.4–321.3). At a coverage level of 50%, indirect protection accounted for 27% of the prevented rotavirus gastroenteritis cases. The balance remained in favour of the vaccine even in a scenario with a high assumption for intussusception case fatality. Conclusions These findings contribute to a better assessment of the rotavirus vaccine benefit–risk balance.

IntroductionTwo vaccines available for protection against rotavirus gastroenteritis (RVGE), Rotarix and RotaTeq, have contributed to a large decrease in the incidence of paediatric diarrhoea in countries where they have been used. However, they have also led to a small increase in the risk of intussusception. Methods: We compare the number of prevented hospitalisations for RVGE to the number of vaccine-induced hospitalised intussusceptions in France. Results: With 9.5% coverage (French 2015 estimation), vaccination was estimated to prevent, annually, a median of 1,074 hospitalisations (2.5th and 97.5th percentiles (2.5th-97.5th): 810-1,378) and 1.4 deaths (2.5th-97.5th: 1.2-1.6) from RVGE. It was also estimated to cause, annually, 5.0 hospitalisations (2.5th-97.5th: 3.2-7.7) and 0.005 deaths (2.5th-97.5th: 0.001-0.015) from intussusception. The benefit-risk ratio is therefore 214 (2.5th-97.5th: 128-362) for hospitalisations and 273 (2.5th-97.5th: 89-1,228) for deaths. Under a hypothetical 92% coverage, rotavirus vaccination with Rotarix would avoid 10,459 (2.5th-97.5th: 7,702-13,498) hospitalisations for RVGE and induce 47.0 (2.5th-97.5th: 25.1-81.4) hospitalisations for intussusception annually, thereby preventing 13.7 (2.5th-97.5th: 11.1-15.2) deaths and inducing 0.05 (2.5th-97.5th: 0.01-0.15) deaths. Conclusion: The benefit-risk ratio in France is similar to that of other European countries.

The increased risk of intussusception after vaccination with the rhesus-human reassortant rotavirus vaccine Rotashield led to its withdrawal in 2005. We assess the risk of intussusception following the pentavalent rotavirus vaccine (RV5) on the basis of worldwide reports to the manufacturer up to May 2014, using a self-controlled case series. The method had to be modified to account for the under-reporting, a specific feature of pharmacovigilance spontaneous reports. The risk of intussusception occurring in either of the 0- to 2-day, 3- to 7-day or 8- to 14-day risk periods, was compared to the risk in the 15- to 30-day period. A total of 502 cases occurring 0-30 days after a vaccine dose were studied, including 188 cases after the first dose, 190 cases after the second dose, and 124 cases after the third dose. The incidence risk ratio relative to the control period was highest for the 3- to 7-day period and equal to 3.45 (95% CI 1.84-6.55), 1.63 (0.86-3.13) and 1.73 (0.86-3.51) after the first, second and third dose, respectively. Rotavirus vaccination with RV5 increases the risk of intussusception 3-7 days following vaccination, mainly after the first dose and marginally after the second and third doses. The risk is small and restricted to a short time window. It does not outweigh the benefit of the vaccination, but parents of vaccinated infants should be informed in order to react appropriately to the first symptoms. With appropriate assumptions about the reporting rate, spontaneous reports of adverse events after vaccination can be studied to evaluate vaccine safety., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

In this paper, we propose new methods for analyzing cases of vaccine adverse events spontaneously reported to a surveillance database. The methods use the self-controlled case series approach, extended in several ways with parametric and nonparametric assumptions to account for the specific features of the data (large amount of underreporting and variation of reporting with time since vaccination). This work was motivated by the documented risk of intussusception after RotaShield vaccination (Wyeth-Lederle Vaccines, Radnor, Pennsylvania) and used worldwide spontaneous reports of intussusception occurring after Rotarix vaccination (GlaxoSmithKline Biologics, Research Triangle Park, North Carolina) collected between January 2004 and February 2010. The estimated risk during the 3- to 7-day period after vaccination was approximately 5 times higher after dose 1 of Rotarix than after dose 2, which is similar to published findings on the same topic. We undertook a large simulation study to evaluate the performance of the method in different scenarios, including its robustness to different sample sizes and time-dependent reporting functions. The bias was generally small, the type I error rate was correctly controlled, and the power to detect a risk ratio of 4 was satisfactory, provided that the sample size was over 100. The proposed methods are an effective way to explore and quantify vaccine safety signals from spontaneous reports.