State-level progress and setbacks in influenza vaccination among adults ≥65: A fifteen-season analysis from 2009/10...

Influenza is a contagious respiratory infection with substantial health and economic consequences worldwide. Annual vaccination is the most effective preventive strategy; however, coverage among older adults remains suboptimal and varies considerably across the United States. This study aimed to examine state-level trends in influenza vaccination coverage among adults aged ≥65 years across fifteen influenza seasons (2009/10-2023/24).

State-level vaccination coverage data for adults aged ≥65 years were obtained from the CDC FluVaxView platform, which reports annual estimates by influenza season. The analysis covered the 2009/10 through 2023/24 influenza seasons. Joinpoint regression was used to assess temporal trends and estimate Annual Percent Change (APC) and Average Annual Percent Change (AAPC) in vaccination coverage.

In the 2023/24 season, all but one state reported coverage rates of at least 50 %; however, only 10 of 51 states reached the 75 % target. Coverage ranged from 49.8 % in Mississippi to 80.6 % in Massachusetts. Over the study period, AAPC significantly increased in three states (Rhode Island, District of Columbia, and Washington) and decreased in four states (Alabama, Mississippi, Louisiana, and Nevada). The COVID-19 pandemic coincided with a temporary increase in coverage in 48 states, but by the 2023/24 season, 44 states had coverages within ±10 % of their pre-pandemic 2019/20 baselines.

Influenza vaccination coverage among older adults remains uneven across states. Although the pandemic prompted short-term gains in vaccine uptake, these improvements were not maintained over time. The findings underscore the need for persistent, state-specific public health strategies to improve coverage in this vulnerable population.