Influenza vaccination coverages in Italy from 1999/00 to 2023/24: a joinpoint regression analysis

Abstract Background Influenza is a contagious respiratory viral infection with significant health and economic impacts worldwide. In Italy, annual epidemics affect approximately 8% of the population. The aim of this study was to assess the trend of flu vaccination coverages in Italy. Methods Data were obtained from the Italian Ministry of Health. The analysis included data from 1999/2000 to 2023/2024 season. Joinpoint regression was used to identify significant changes in coverage trends over time, calculating Annual Percentage Change (APC) and Average Annual Percent Change (AAPC). Results Coverages vary between and within age groups over the study period. Among the paediatric population, the highest vaccination coverage was observed in the 5-8 years group (22.6% in 2022/2023), while the lowest was recorded in the 15-17 years group (4.5% in 2020/2021). A positive AAPC was observed in all the age groups, except for the 15-17 years group (-5.58%, 95%CI: -9.35;-2.07; p = 0.002). In adults aged 18-44 years, the peak coverage was 5.9% (2020/2021) with an AAPC of + 0.34% (95%CI: -4.11-3.81; p = 0.89), while in the 45-64 years group, it reached 16.8% (2020/2021) with an AAPC of + 0.89% (95%CI: -2.07-4.20; p = 0.46). In the general population, coverage reached a maximum of 23.7% in 2020/2021, with an overall AAPC of + 2.33% (95%CI 1.75%-3.00%, p<.001). In the elderly population the highest value was 68.3% in 2005/2006, and an overall AAPC of + 0.83% (95%CI: 0.3554 to 1.4401, p = 0.003). A significant downward trend is also observed in latest years, from 2020/2021 to 2023/2024, with an APC of -4.30% (95CI%: -10.58 to -1.25, p = 0.0048). Similarly, the increases in coverages observed during the pandemic decline to pre-pandemic values during the following seasons in all other age groups. Conclusions Despite the proven efficacy and safety of the vaccine, hesitancy has gained momentum in Italy, resulting in persistently low coverage rates, below target thresholds, particularly in high-risk age groups. Key messages • A multifaceted approach is needed, including expanding free vaccination programs, implementing school-based initiatives, engaging healthcare workers, and enhancing public awareness campaigns. • A coordinated national effort, led by the Italian Ministry of Health, is essential to achieving higher coverage rates, reach threshold target and reducing the burden of influenza.