Brand-Specific Enhanced Safety Surveillance of GSK’s Quadrivalent Seasonal Influenza Vaccine in Belgium, Germany and Spain for the 2018/2019 Season

Introduction Seasonal influenza causes numerous deaths worldwide each year. Annual vaccination for disease prevention is crucial. Seasonal vaccines are updated each year to closely match circulating strains. Objective To comply with European Medicines Agency (EMA) guidance, an enhanced safety study was conducted to rapidly collect and assess adverse events (AEs) within 7 days following vaccination with GSK’s inactivated quadrivalent seasonal influenza vaccine (IIV4) in 2018/2019. Methods A customised AE reporting card (AERC) and standardised electronic data reporting application were used in Belgium, Germany and Spain in adult and paediatric subjects in this study. Results In 2018, 1060 subjects vaccinated with one dose of GSK’s IIV4 were enrolled (all subjects in Belgium and Germany were adults, and 75% and 25% of subjects in Spain were children and adults, respectively). In Spain, 139 eligible children later received a second dose. Overall 1035 subjects completed the study. After dose 1 and dose 2, 98.3% and 100% of subjects, respectively, returned the completed AERC. Over the study period, 43.0% (456/1060 post dose 1) and 23.7% (33/139 post dose 2) of subjects reported at least one AE within 7 days after immunisation. The most frequently reported categories of AEs were General and Administration Site (e.g. injection site pain, swelling, erythema) and Respiratory Disorders (e.g. rhinorrhoea, cough, nasal congestion). There were no deaths and no serious AEs deemed related to GSK’s IIV4. Conclusion In compliance with EMA guidance, this study design allowed for near real-time assessment of AEs. No safety signals were detected at any point during the study period. The study supports and confirms the acceptable safety profile of GSK’s IIV4. ClinicalTrials.gov identifier NCT03688620.