Department of Microbiology, Infectious Diseases, and Immunology, Faculty of Medicine, University of Montreal, Canada; Research Institute - CHU Sainte Justine, Canada.
Department of Microbiology, Infectious Diseases, and Immunology, Faculty of Medicine, University of Montreal, Canada; Institut national de santé publique du Québec, Canada.
Vaccine. 2022 Sep 16;40(39):5732-5738. doi: 10.1016/j.vaccine.2022.08.012. Epub 2022 Aug 27.
Healthcare administrative databases are a rich source of information that could be leveraged to estimate real-world influenza vaccine effectiveness (VE). We aimed to evaluate the VE of standard egg-based influenza vaccines and determine if administrative healthcare data provide accurate VE estimates compared to the US CDC data.
This retrospective cohort study was conducted during the 2018-2019 influenza season. Individuals who had at least one relevant record per year between 2015 and 2019 in their electronic medical record were included. Individuals were considered protected 14 days after receiving an influenza vaccine. The outcome was the occurrence of medically attended influenza-like illness (MA-ILI) defined by clinical diagnostic codes. Adjusted odds ratios (aORs) were derived from multivariate logistic regression and adjusted VE (aVEs) were calculated using 100 × (1-aORs).
A total of 5,066,980 individuals were included in the analysis with 1,307,702 (25.8%) considered vaccinated. Overall, the median age was 54 (IQR, 32-66) and 58.1% were female. Vaccine protection against MA-ILI was moderate in children and low in adults. All estimates were lower than VEs reported by the CDC for the 2018-2019 influenza season. Our results were robust to potential loss to follow up, but misclassification bias and residual confounding led to underestimation of the 2018-2019 aVE. When stratified by the number of primary care visits, aVE estimates and vaccination coverage increased with the number of primary care visits, reaching estimates similar to those obtained by the US CDC and US national vaccination coverage among those with ≥ 6 primary care visits, resulting in significant positive vaccine protection in frequent healthcare users.
Moderate and low aVEs were observed during the 2018-2019 season using administrative healthcare data, which was likely due to detection and misclassification biases, correlated with healthcare seeking behaviour, leading to an underestimation of the 2018-2019 influenza VE.
医疗保健管理数据库是一个丰富的信息来源，可以利用这些信息来估计现实世界中的流感疫苗有效性（VE）。我们旨在评估标准基于鸡蛋的流感疫苗的 VE，并确定与美国疾病控制与预防中心（CDC）的数据相比，医疗保健管理数据是否提供了准确的 VE 估计。
这是一项回顾性队列研究，于 2018-2019 流感季节进行。在 2015 年至 2019 年期间，电子病历中每年至少有一条相关记录的个人被纳入研究。个人在接种流感疫苗后 14 天被认为受到保护。结局是由临床诊断代码定义的有医疗记录的流感样疾病（ILI）的发生。调整后的优势比（aORs）来自多变量逻辑回归，使用 100×（1-aORs）计算调整后的 VE（aVE）。
共有 5066980 人纳入分析，其中 1307702 人（25.8%）被认为接种了疫苗。总体而言，中位年龄为 54（IQR，32-66）岁，58.1%为女性。疫苗对 ILI 的保护作用在儿童中为中度，在成人中为低度。所有估计值均低于 CDC 报告的 2018-2019 流感季节的 VE。我们的结果对潜在的随访丢失具有稳健性，但由于分类错误偏倚和残余混杂因素，导致对 2018-2019 年 aVE 的低估。按初级保健就诊次数分层时，aVE 估计值和疫苗接种率随着初级保健就诊次数的增加而增加，在就诊次数≥6 的患者中，达到与 CDC 和美国全国疫苗接种率相似的估计值，导致经常使用医疗保健的患者中出现显著的疫苗保护作用。
使用医疗保健管理数据观察到 2018-2019 年季节中度和低度 aVE，这可能是由于检测和分类错误偏倚与寻求医疗保健行为相关，导致对 2018-2019 年流感 VE 的低估。
