Abstract：
UNASSIGNED: The question of whether influenza vaccine effectiveness (VE) wanes over the winter season is still open and some contradictory findings have been reported. This study investigated the possible decline in protection provided by the available influenza vaccines.
UNASSIGNED: An individual-level pooled analysis of six test-negative case-control studies conducted in Italy between the 2018/2019 and 2022/2023 seasons was performed. Multivariable logistic regression analyses were performed to estimate weekly change in the odds of testing positive for influenza 14 days after vaccination.
UNASSIGNED: Of 6490 patients included, 1633 tested positive for influenza. Each week that had elapsed since vaccination was associated with an increase in the odds of testing positive for any influenza (4.9%; 95% CI: 2.0-8.0%) and for A(H3N2) (6.5%; 95% CI: 2.9-10.3%). This decline in VE was, however, significant only in children and older adults. A similar increase in the odds of testing positive was seen when the dataset was restricted to vaccinees only. Conversely, VE waning was less evident for A(H1N1)pdm09 or B strains.
UNASSIGNED: Significant waning of VE, especially against influenza A(H3N2), may be one of the factors associated with suboptimal end-of-season VE. Next-generation vaccines should provide more durable protection against A(H3N2).
UNASSIGNED: An individual-level pooled analysis of six test-negative case-control studies conducted in Italy between the 2018/2019 and 2022/2023 seasons was performed. Multivariable logistic regression analyses were performed to estimate weekly change in the odds of testing positive for influenza 14 days after vaccination.
UNASSIGNED: Of 6490 patients included, 1633 tested positive for influenza. Each week that had elapsed since vaccination was associated with an increase in the odds of testing positive for any influenza (4.9%; 95% CI: 2.0-8.0%) and for A(H3N2) (6.5%; 95% CI: 2.9-10.3%). This decline in VE was, however, significant only in children and older adults. A similar increase in the odds of testing positive was seen when the dataset was restricted to vaccinees only. Conversely, VE waning was less evident for A(H1N1)pdm09 or B strains.
UNASSIGNED: Significant waning of VE, especially against influenza A(H3N2), may be one of the factors associated with suboptimal end-of-season VE. Next-generation vaccines should provide more durable protection against A(H3N2).
摘要：
■流感疫苗有效性（VE）是否在冬季减弱的问题仍然存在，并且已经报道了一些相互矛盾的发现。这项研究调查了可用流感疫苗提供的保护的可能下降。
■对2018/2019年至2022/2023年季节之间在意大利进行的六项测试阴性病例对照研究进行了个人水平的汇总分析。进行了多变量逻辑回归分析，以估计疫苗接种后14天流感检测呈阳性的几率的每周变化。
■包括6490名患者，1633年流感检测呈阳性。自疫苗接种以来的每个星期都与任何流感（4.9％;95％CI：2.0-8.0％）和A（H3N2）（6.5％;95％CI：2.9-10.3％）的检测呈阳性的几率增加有关。VE的下降是，然而,仅在儿童和老年人中显著。当数据集仅限于接种者时，检测阳性的几率也有类似的增加。相反，对于A（H1N1）pdm09或B菌株，VE减弱不明显。
■VE显著减弱，特别是针对甲型流感（H3N2），可能是与赛季末VE次优相关的因素之一。下一代疫苗应提供更持久的抗A（H3N2）保护。
■对2018/2019年至2022/2023年季节之间在意大利进行的六项测试阴性病例对照研究进行了个人水平的汇总分析。进行了多变量逻辑回归分析，以估计疫苗接种后14天流感检测呈阳性的几率的每周变化。
■包括6490名患者，1633年流感检测呈阳性。自疫苗接种以来的每个星期都与任何流感（4.9％;95％CI：2.0-8.0％）和A（H3N2）（6.5％;95％CI：2.9-10.3％）的检测呈阳性的几率增加有关。VE的下降是，然而,仅在儿童和老年人中显著。当数据集仅限于接种者时，检测阳性的几率也有类似的增加。相反，对于A（H1N1）pdm09或B菌株，VE减弱不明显。
■VE显著减弱，特别是针对甲型流感（H3N2），可能是与赛季末VE次优相关的因素之一。下一代疫苗应提供更持久的抗A（H3N2）保护。
