Influenza Vaccination in Spain: Understanding the Impact of Suboptimal Coverage on Health, Society, and the Economy

Influenza is an acute viral respiratory infection that generates a substantial clinical and socioeconomic burden, especially among high-risk populations such as older adults. In Spain, influenza accounts for approximately €128 million in direct healthcare costs each season, with 80% of expenditures concentrated in individuals over 45 years of age. Vaccination remains the most effective intervention to prevent complications and reduce healthcare pressure. However, current coverage rates are consistently below international targets and continue to decline. In this context, there is an urgent need to strengthen vaccination uptake, especially among high-risk groups. Increasing vaccination uptake is essential to lessen the clinical, societal, and economic burden of influenza, since modest improvements in coverage have a significant impact on public health outcomes and economic resilience. In fact, previously published modeling analyses indicate that a 1% reduction in national vaccination coverage could result in over 6400 additional influenza cases and an additional economic burden of €1.54 million per season. Furthermore, increasing coverage to 75% in Spain could prevent approximately 180,300 additional cases-equivalent to 20% of the total-which would translate into potential savings of €43 million (€26 million in direct medical costs and €17 million in work absenteeism costs). This manuscript provides an overview of the influenza burden and vaccination landscape in Spain, focusing on clinical, societal, and economic implications of suboptimal coverage, as well as the current challenges and opportunities to improve uptake. Available evidence indicates that influenza vaccination reduces severe outcomes and healthcare burden, suggesting that mildly improving coverage in Spain could yield substantial health and economic benefits. Taken together, these findings support influenza vaccination as a public health priority and a relevant investment for health systems.