Post-marketing Surveillance of a Quadrivalent Influenza Vaccine (Vaxigrip Tetra) in South Korea.

INTRODUCTION

In 2017, a quadrivalent inactivated split-virion influenza vaccine (QIV; Vaxigrip Tetra®, Sanofi) was licensed in South Korea for active immunization against influenza A and influenza B viruses in individuals aged 3 years or older, which was subsequently extended to individuals aged 6 months or older in 2018. Post-marketing surveillance trials are mandatory in South Korea to retain drug licensure. Here, we assessed the safety of QIV in routine clinical practice in South Korea.

METHODS

This was an open, multicenter, observational, active safety surveillance study conducted between 20 June 2017 and 19 June 2021 at 10 study sites in South Korea in individuals aged 3 years or older who received a single dose of QIV during a routine healthcare visit. The participants or their legally acceptable representatives were instructed to record any adverse reactions (solicited events) and unsolicited non-serious adverse events (AE) in diary cards, and notify study investigators in case of serious adverse events (SAE).

RESULTS

Overall, 663 participants were included in this study. There were no AEs leading to study termination, and no SAEs reported. Injection site pain (278 [41.9%]) was the most frequent solicited injection site reaction, with myalgia (250 [37.7%]) and malaise (236 [35.6%]) the most frequent solicited systemic reactions. Grade 3 solicited injection site and systemic reactions were reported by 8 (1.2%) and 13 (2.0%) participants, respectively; most participants with solicited reactions recovered without the need for further action. Overall, 39 (5.9%) participants experienced 49 unsolicited non-serious AEs with the most frequently reported being nasopharyngitis (19 [2.9%]). Grade 3 unsolicited non-serious adverse events were reported in 1 (0.2%) participant. None of the unsolicited non-serious AEs were considered to be related to QIV.

CONCLUSION

This post-marketing surveillance study confirms that QIV is well tolerated and has an acceptable safety profile in routine practice in South Korea. No unexpected safety concerns were identified.

TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT05406180.