Epidemiological studies suggest that humans who receive repeated annual immunization with influenza vaccine are less well protected against influenza than those who receive vaccine in the current season only. To better understand potential mechanisms underlying these observations, we vaccinated influenza-naive ferrets either twice, 10 months apart (repeated vaccination group; RV), or once (current season only group; CS), using a prime-boost regimen, and then challenged the ferrets with A/Hong Kong/4801/2014(H3N2). Ferrets that received either vaccine regimen were protected against influenza disease and infection relative to naive unvaccinated ferrets, but the RV group shed more virus, especially at the peak of virus shedding 2 days post infection (p < 0.001) and regained weight more slowly (p < 0.05) than those in the CS group. Qualitative, rather than quantitative, differences in the antibody response may affect protection after repeated influenza vaccination.

流行病学研究表明，每年重复接种流感疫苗的人对流感的保护效果不如仅在当前季节接种疫苗的人。为了更好地了解这些观察结果背后的潜在机制，我们使用初免-加强方案对未接触过流感的雪貂进行两次疫苗接种，间隔 10 个月（重复疫苗接种组；RV），或一次（仅当前季节组；CS），然后进行挑战患有 A/Hong Kong/4801/2014(H3N2) 的雪貂。与未接种疫苗的雪貂相比，接受任一疫苗方案的雪貂都能免受流感疾病和感染，但 RV 组排出更多病毒，尤其是在感染后 2 天病毒排出高峰时 ( p < 0.001)，并且体重恢复速度更慢 ( p < 0.05) 高于 CS 组。抗体反应的定性而非定量差异可能会影响重复接种流感疫苗后的保护作用。