OBJECTIVES: The 2021/22 influenza season was still marked by the circulation of the Sars-CoV-2 responsible for the COVID-19 pandemic. Leveraging past research, we aimed at comparing pre and post-COVID-19 periods influenza vaccine coverage rate (VCR). We also explored the evolution of influenza VCR between the last two seasons.

METHODS: We conducted secondary desk research to collect annual influenza VCR from the seasons 2010/11 to 2021/22 in France, Italy, Spain, UK, Canada and US. Government and public health agency websites were consulted and VCR were extracted for all populations eligible to influenza vaccination. We used non-parametric Wilcoxon signed-rank tests to investigate significant variations in VCR for the pooled 2020/22 seasons compared to previous seasons (overall and by age-group). We also looked at VCR evolution between the 2020/21 and 2021/22 seasons.

RESULTS: Overall VCR in France increased by 12.26% in 2020/22 compared to previous seasons (p=0.001). Significant increases in VCR in both adults aged 65+ years and below 65 years at-risk were observed in France, UK and the US with +12.56% / +12.43% and +8.98% respectively (all p=0.001). Significant results were also observed in at-risk adults <65y with +7.17% (UK) and +23.58% (US). No significant changes were observed in any eligible groups in Canada, and VCR for Italy and Spain were not available at the time of the study. However, decreases in VCR were observed in 2021/22 compared to 2020/21, with -3.20% in overall VCR in France and -16.10% and -7.50% in the US for the ≥18y and ≥65y age groups respectively.

CONCLUSIONS: Significant augmentations in influenza VCR were observed during the 2020/22 seasons compared to the pre-COVID-19. However, drops in VCR were observed in multiple age groups and countries in 2021/22 compared to the previous season, potentially demonstrating early signs of vaccine fatigue across populations.