Post-Marketing Active Surveillance of Adverse Reactions Following Influenza Cell-Based Quadrivalent Vaccine: An Italian Prospective Observational Study.

Pasquale Stefanizzi,Francesco Paolo Bianchi,Domenica Ancona,Paolo Stella,Savino Soldano,Silvio Tafuri,Sabrina Lattanzio,Margherita Padovano,Maria Dell'Aera,Sara De Nitto,Giuseppe Spinelli

doi:10.3390/vaccines9050456

Abstract

Since the influenza season 2018/19, the Italian Ministry of Health recommended a dose of cell-based quadrivalent vaccine (Flucelvax Tetra) for HCWs (healthcare workers), because this vaccine seemed more efficacious in the prevention of AH3N2 virus. Due to the lack of pre-registration data, the safety profile of this new vaccine must be investigated in post-marketing surveillance. The aim of our study is to evaluate, through a post-marketing active surveillance program developed during the 2019/20 influenza season, any Adverse Events Following Immunization (AEFIs) that happened in the 7 days after immunization with Flucelvax Tetra. The study was carried out in a sample of HCWs of Policlinico General University-Hospital (Apulia, South Italy). AEFIs were classified as ‘serious’ or ‘not serious’ according to the WHO (World Health Organization) guidelines; the WHO causality assessment algorithm was applied to classify serious AEFIs. A total of 741 HCWs were enrolled, and 430 AEFIs (reporting rate: 58.0 (95%CI: 54.4–61.6) × 100 enrolled) were recorded. Of these, 429 of 430 (99.8%; reporting rate: 57.8 (95%CI: 54.2–61.5) × 100 enrolled) were classified as not serious and one (0.2%; reporting rate: 0.13 (0.03–0.75) × 100 enrolled) was classified as serious. Local reactions were the adverse reaction reported most frequently (88%); regarding the serious AEFI, causality assessment excluded the causal link with the administration of the vaccine. All the AEFIs resolved without sequelae. Flucelvax Tetra showed a profile of high safety. Due to their characteristics of greater sensitivity than passive surveillance, active surveillance programs can be useful in defining the safety profiles of a given vaccine/drug in certain population subgroups.

Highlights

The vaccination of healthcare workers (HCWs) is an effective measure of individual and collective disease protection
The aim of our study is to evaluate through a post-marketing active surveillance program, any Adverse Events Following Immunization (AEFIs) in the 7 days after immunization with Flucelvax Tetra in a sample of HCWs of Policlinico General University-Hospital (Apulia, Italy)
A total of 1481 HCWs were vaccinated during the 2019/20 influenza season; of these, 775 (52.3%) joined on a voluntary basis the active surveillance program

Summary

Introduction

The vaccination of healthcare workers (HCWs) is an effective measure of individual and collective disease protection. It protects both HCWs from the occupational risk of infectious disease and patients from the risk of infection in the nosocomial environment [1]. Since the influenza season 2018/19, the Italian Ministry of Health recommended a dose of cell-based quadrivalent vaccine (Flucelvax Tetra, Seqirus S.r.l., Siena, Italy) [6] for HCWs. In October 2018, the vaccine was authorized for use from 9 years of age (single dose of 0.5 mL) by the European Medicines Agency (EMA), and in December of the same year, it obtained the final approval by the European Commission [7,8]

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