Co-administration with Men-B vaccine increases Rotavirus vaccination coverage: A 5-year regionwide retrospective cohort study (STORM study)

Introduction: In Italy Rotavirus vaccination (RVV) is provided free of charge from 2018, however, the coverage is scattered and suboptimal. The narrow time frame to complete the schedule is a barrier to uptake, and co-administration with other vaccines may potentially increase the coverage. Although the co-administration of RV vaccine and Meningococcal Group B vaccine (MenB) is not included in the product labels, we aimed at studying its impact on RVV coverage. Methods: This Surveillance study on Timing and cOverage of Rotavirus and MenB vaccine co-administration (STORM study) used the Regional Vaccination Registry to collect data about children born in Campania Region between January 2016 and December 2020, and receiving vaccines scheduled in the first year of life. Results: Among the 224,110 children enrolled, 60,614 (27.0%) completed the RVV schedule, with a vaccination rate that increased over time from 1.15% in 2016 to 56.92% in 2020. The first and last dose of RVV schedule were administered beyond the recommended time in 6% of the study population, respectively. Co-administration of RV vaccine with MenB vaccine increased from 0.7 % in 2016 to 46.85 % in 2020. Children receiving RV/MenB vaccines concomitantly had a significantly higher chance of completing the RV schedule compared to those receiving RVV alone during a specific appointment (94.78 % vs 72.26 %, Prevalence Ratio -PR- 1.275, 95 %CI 1.245-1.295p < 0.00001). The positive driving effect of RV/MenB co-administration was more evident for children receiving pentavalent (PR 1.288) than monovalent RVV (PR 1.115) which was confirmed when adjusted for confounding variables (i.e., year of vaccination, local district, gender). Conclusions: Although still far from the target, RVV coverage has increased in recent years in Campania Region. Co-administration with MenB vaccine may aid in increasing RVV coverage, especially for pentavalent RVV. Further safety data are needed to support co-administration as a key tool to increase coverage.