The purpose of this Phase 4 study is to comply with the European Medicines Agency (EMA) guidance on enhanced safety surveillance for seasonal influenza vaccines in the European Union (EU) and aims to assess adverse events of interest (AEIs) experienced within 7 days post-vaccination with GSK's quadrivalent seasonal influenza vaccine (AlphaRix Tetra in Belgium; Influsplit Tetra in Germany, Fluarix Tetra in Spain).

The key objective of the EMA enhanced safety surveillance is to rapidly detect a significant increase in the frequency and/or severity of expected reactions (local, systemic or allergic reactions) that may indicate a potential risk.

The study is a passive enhanced safety surveillance aiming to collect prospectively AEIs and/or other AEs experienced within 7 days post-vaccination with GSK's quadrivalent seasonal influenza vaccine, using customized Adverse Drug Reaction cards. Data will be collected via the healthcare provide (HCP) or study medical staff who administer the seasonal influenza vaccination or who provide the informed consent form and the ADR cards.

Results

The results of this trial were published on October 8, 2019.

Results: Between week 40 and 52, 1060 vaccinated subjects were enrolled (31.0% Belgium, 26.2% Germany, and 42.7% Spain) covering all ages for which IIV4 is indicated (32.0% aged 6 months-17 years, 33.8% 18-65 years, and 34.2% over 65 years). Pediatric subjects less than 9 years old (n = 139) received two doses. Following dose 1 and dose 2, 98.2% and 100%, respectively, returned the completed AERC recording any AEs. Following dose 1 and dose 2, 454 and 34 subjects, respectively, reported at least one AE (most frequently expected general and injection site symptoms and respiratory symptoms).

Conclusion: All reported AEs were expected as per summary product characteristics (smPC). No safety signals that impact public health or alter the benefit-risk profile of GSK's IIV4 were identified. Subjects from all vaccinated age groups were enrolled and the use of AERCs allowed rapid monitoring and analysis of reported AEs.