Modelling, Epidemiology and Data Science, Sanofi Vaccines, Lyon, France.
Quinten Health, Lyon, France.
Clin Infect Dis. 2023 Oct 5;77(7):1032-1042. doi: 10.1093/cid/ciad322.
High-dose (HD) influenza vaccine offers improved protection from influenza virus infection among older adults compared with standard-dose (SD) vaccine. Here, we explored whether HD vaccine attenuates disease severity among older adults with breakthrough influenza.
This was a retrospective cohort study of US claims data for influenza seasons 2016-2017, 2017-2018, and 2018-2019, defined as 1 October through 30 April, among adults aged ≥65 years. After adjusting the different cohorts for the probability of vaccination conditional on patients' characteristics, we compared 30-day mortality rate post-influenza among older adults who experienced breakthrough infection after receipt of HD or SD influenza vaccines and among those not vaccinated (NV).
We evaluated 44 456 influenza cases: 23 109 (52%) were unvaccinated, 15 037 (33.8%) received HD vaccine, and 6310 (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.
HD vaccination was associated with lower post-influenza mortality among older adults with breakthrough influenza, even during seasons when antigenically drifted H3N2 circulated. Improved understanding of the impact of different vaccines on attenuating disease severity is warranted when assessing vaccine policy recommendations.
与标准剂量（SD）疫苗相比，高剂量（HD）流感疫苗可提高老年人对流感病毒感染的保护。在此，我们探讨了 HD 疫苗是否可减轻突破性流感患者的疾病严重程度。
这是一项针对美国索赔数据的回顾性队列研究，流感季节为 2016-2017 年、2017-2018 年和 2018-2019 年，定义为 10 月 1 日至 4 月 30 日，患者年龄≥65 岁。在根据患者特征调整了不同队列中疫苗接种概率后，我们比较了接受 HD 或 SD 流感疫苗后发生突破性感染的老年人与未接种疫苗（NV）者的流感后 30 天死亡率。
我们评估了 44456 例流感病例：23109 例（52%）未接种疫苗，15037 例（33.8%）接受了 HD 疫苗接种，6310 例（14.2%）接受了 SD 疫苗接种。在所有 3 个季节中，与 NV 相比，HD 疫苗接种均显著降低了突破性病例的死亡率，降幅在 17%至 29%之间。在 2016-2017 年季节中，由于循环流感病毒与选定疫苗株之间存在良好匹配，与 NV 相比，SD 疫苗接种可降低 25%的死亡率。当比较 HD 与 SD 队列时，在过去 2 个季节中，当疫苗株与循环 H3N2 病毒不匹配时，接受 HD 疫苗接种的患者死亡率降低幅度更高，但无统计学意义。
即使在 H3N2 抗原漂移流行的季节中，HD 疫苗接种也与突破性流感老年人的流感后死亡率降低相关。在评估疫苗政策建议时，需要更好地了解不同疫苗对减轻疾病严重程度的影响。
