Safety Profile of GSK's Inactivated Quadrivalent Seasonal Influenza Vaccine in Belgium, Germany and Spain: Passive Enhanced Safety Surveillance Study for the 2019/2020 Influenza Season

An 8-Year Prospective, Observational, Multi-centre Post-Marketing Safety Surveillance Study Conducted in South Korea (2014-2022) Following the Introduction of GSK's Inactivated Quadrivalent Seasonal Influenza Vaccine (Fluarix Tetra) for Subjects Aged 6 Months and Older

INTRODUCTION

Seasonal influenza is associated with substantial public health burden. The objective of this study was to assess the safety of inactivated quadrivalent seasonal influenza vaccine (IIV4, Fluarix Tetra, GSK, Belgium) in subjects aged ≥ 6 months in Korea.

METHODS

This prospective, observational, non-comparative, multi-centre post-marketing surveillance study was conducted in Korea in subjects aged ≥ 3 years for 6 years (2014-2020) and extended to subjects aged 6-35 months for 4 years (2018-2022). Subjects received IIV4 in routine clinical practice according to local prescribing information. Adverse events (AEs) were recorded over 21 days post-vaccination.

RESULTS

The group aged ≥ 3 years included 701 subjects (mean 31.97 years, range 3-86 years, 46.36% male), and the group aged 6-35 months included 687 subjects (mean 16.31 months, 47.02% male). In the group aged ≥ 3 years, 98 subjects (13.98%) reported 140 AEs, of which 42 events in 34 subjects (4.85%) were adverse reactions to vaccine (ARVs). Most of the ARVs were expected, mainly administration site reactions. There were seven mild unexpected ARVs. In the group aged 6-35 months, 248 AEs were reported in 149/687 subjects (21.69%). ARVs were reported in 25/687 subjects (3.64%, 29 events); one was considered unexpected. There were five serious AEs overall, none of which were considered related.

CONCLUSION

No safety concerns were found during this surveillance study of IIV4 in subjects aged ≥ 6 months in Korea. The findings of this study suggest IIV4 is safe and well tolerated for use in all age groups with a vaccine indication.

Three seasons of enhanced safety surveillance of a cell culture-based quadrivalent influenza vaccine

The objective of this paper is to summarize annual enhanced safety surveillance activity across three seasons (2019/20-2021/22) for cell culture-based quadrivalent influenza vaccine (QIVc; Flucelvax® Tetra) in all age groups. This activity was conducted in primary care setting in Genoa (Italy) during the seasons 2019/20, 2020/21 and 2021/22. All adverse events registered within the first seven days following immunization were analyzed by season, type, age group and seriousness. Over three seasons, 3,603 QIVc exposures were recorded within the enhanced passive safety surveillance activity. No safety signals were identified. The overall reporting rates of individual case safety reports for the seasons 2019/20, 2020/21 and 2021/22 were 1.75%, 0.48% and 0.40%, respectively. The average number of adverse events per individual case safety report was similar (range 3.3-3.8 adverse events per case report) across the three seasons. Most adverse events were reactogenic in nature. The rate of adverse events was similarly low in all age groups. Enhanced passive safety surveillance activity is a feasible approach for the post-marketing monitoring of seasonal influenza vaccines. Within its limitations, results of this study support the favorable safety profile of QIVc. These safety data could further bolster public trust in influenza vaccines with the goal to increase vaccination uptake in all target groups.

Enhanced passive safety surveillance of Influvac® and Influvac® Tetra: Results from seven consecutive seasons

BACKGROUND AND OBJECTIVES

In 2014, the European Medicines Agency (EMA) set out requirements for an enhanced safety surveillance for seasonal influenza vaccines. This paper presents data from the yearly Enhanced Passive Safety Surveillance (EPSS) implemented for Influvac® since season 2014/15 and continued for Influvac® Tetra from season 2018/19 onwards.

METHODS

In seven consecutive seasons, an EPSS, aiming for at least 1,000 vaccinees (additional target of 100 vaccinees per five predefined age groups), was conducted in Germany, where market characteristics were expected to allow for a quick generation of representative data. Reactogenicity data in terms of reporting rates, severity and duration of pre-specified local and systemic adverse events of interest (AEI) were collected using response cards, which were completed by vaccinees and returned seven days after vaccination via regular mail. In addition, response cards contained a call center number to enhance reporting of other than pre-specified adverse events.

RESULTS

The primary target of at least 1,000 vaccinees was surpassed in all seasons, as was the additional target of 100 adults and elderly. Reactogenicity data were in line with known safety profile of Influvac® and Influvac® Tetra. In children, the target was mostly met in seasons when the EPSS was conducted for Influvac®, but not in seasons when it was conducted for Influvac® Tetra. Although the data for Influvac® Tetra are based on a low number of paediatric vaccinees, they do not indicate a different reactogenicity profile of Influvac® Tetra compared with Influvac®. No signals were identified.

CONCLUSION

The EPSS set up for Influvac® and Influvac® Tetra proved a robust and effective methodology to comply with the objectives of EMÁ's guidance on enhanced safety surveillance of seasonal influenza vaccines. Safety data from seven consecutive seasons confirmed the favourable safety profile of both vaccines.

Brand-Specific Enhanced Safety Surveillance Study of GSK's Quadrivalent Seasonal Influenza Vaccine, Conducted During the COVID-19 Pandemic, in Belgium, Germany and Spain, for the 2020/21 Season

INTRODUCTION

Seasonal influenza poses a major public health burden worldwide. Influenza vaccines, updated yearly to match circulating strains based on World Health Organization (WHO) recommendations, are the cornerstone of prevention and require regular monitoring. The COVID-19 pandemic is expected to cause logistical, site access and medical staff constraints and could affect the safety profile of influenza vaccines.

METHODS

Following European Medicines Agency guidance, an enhanced safety surveillance (ESS) study assessed the frequency and severity of predefined and other adverse events (AEs) occurring within 7 days of receiving GSK's inactivated quadrivalent seasonal influenza vaccine (IIV4), in Belgium, Germany and Spain in 2020/21, using adverse drug reaction (ADR) cards.

RESULTS

During the 2020/21 influenza season, 1054 participants vaccinated with GSK's IIV4 were enrolled (all adults in Belgium and Germany, 30% adults/70% children in Spain); 96 eligible children received a second dose. Overall, 1042 participants completed the study. After doses 1 and 2, 98.9% and 100% of participants, respectively, returned their completed ADR card. After doses 1 and 2, 37.8% (398/1054) and 13.5% (13/96) of participants, respectively, reported at least one AE. The most frequently reported categories of AEs were "general disorders and administration site conditions" (e.g. injection site pain) and "nervous system disorders" (e.g. headache). There were no deaths or serious AEs deemed related to GSK's IIV4.

CONCLUSION

This ESS study assessed AEs in near real time. The COVID-19 pandemic did not alter the safety profile of GSK's IIV4. No safety signals were detected during the study, which confirms the excellent safety profile of GSK's IIV4.