Why carry out this study?

Seasonal influenza vaccination is the most effective way to prevent influenza. As influenza viruses change regularly, vaccines are updated each year to target circulating strains and require continuous monitoring and rapid evaluation, according to European Medicines Agency guidelines.

We conducted an enhanced safety surveillance study to rapidly assess the frequency and severity of adverse events (AEs) occurring within 7 days of receiving GSK’s inactivated quadrivalent seasonal influenza vaccine (IIV4) in 2020/21, in children and adults, in Belgium, Germany and Spain.

What was learned from the study?

Despite the significant disruption caused by the COVID-19 pandemic, this study achieved near-real-time data collection of AEs in vaccinated children and adults. No unexpected safety issues were found to be associated with GSK’s IIV4. At the end of this study, which involved 1054 participants, 37.8% and 13.5% of participants reported at least one AE after doses 1 and 2, respectively. The most common AEs following dose 1 (in adults and children) were pain, swelling or redness around the injection site, fatigue and headache. Following dose 2 (in children), the most common AE was injection site pain.

The COVID-19 pandemic did not alter the safety profile of GSK’s IIV4.