Among older adults, receipt of high-dose (HD) influenza vaccine was associated with lower post-influenza mortality compared with standard-dose (SD) products or no vaccination, a study shows. Even during seasons when antigenically drifted H3N2 circulated, receipt of the high-dose product was beneficial. “Improved understanding of the impact of different vaccines on attenuating disease severity is warranted when assessing vaccine policy recommendations,” the authors concluded.
The retrospective cohort study analyzed U.S. claims data for influenza seasons 2016–2017, 2017–2018, and 2018–2019, among adults aged 65 years or older. Based on 30-day mortality rates post-influenza among older adults, the study showed: “We evaluated 44,456 influenza cases: 23,109 (52%) were unvaccinated, 15,037 (33.8%) received HD vaccine, and 6,310 (14.2%) received SD vaccine. Significant reductions in mortality rates among breakthrough cases were observed across all 3 seasons for HD vs NV, ranging from 17% to 29% reductions. A significant mortality reduction of 25% was associated with SD vaccination vs NV in the 2016–2017 season when there was a good match between circulating influenza viruses and selected vaccine strains. When comparing HD vs SD cohorts, mortality reductions were higher among those who received HD in the last 2 seasons when mismatch between vaccine strains and circulating H3N2 viruses was documented, albeit not significant.”