The impact of underreported infections on vaccine effectiveness estimates derived from retrospective cohort studies.

IF 6.4 2区 医学 Q1 PUBLIC, ENVIRONMENTAL & OCCUPATIONAL HEALTH
Chiara Sacco, Mattia Manica, Valentina Marziano, Massimo Fabiani, Alberto Mateo-Urdiales, Giorgio Guzzetta, Stefano Merler, Patrizio Pezzotti
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引用次数: 0

Abstract

Background: Surveillance data and vaccination registries are widely used to provide real-time vaccine effectiveness (VE) estimates, which can be biased due to underreported (i.e. under-ascertained and under-notified) infections. Here, we investigate how the magnitude and direction of this source of bias in retrospective cohort studies vary under different circumstances, including different levels of underreporting, heterogeneities in underreporting across vaccinated and unvaccinated, and different levels of pathogen circulation.

Methods: We developed a stochastic individual-based model simulating the transmission dynamics of a respiratory virus and a large-scale vaccination campaign. Considering a baseline scenario with 22.5% yearly attack rate and 30% reporting ratio, we explored fourteen alternative scenarios, each modifying one or more baseline assumptions. Using synthetic individual-level surveillance data and vaccination registries produced by the model, we estimated the VE against documented infection taking as reference either unvaccinated or recently vaccinated individuals (within 14 days post-administration). Bias was quantified by comparing estimates to the known VE assumed in the model.

Results: VE estimates were accurate when assuming homogeneous reporting ratios, even at low levels (10%), and moderate attack rates (<50%). A substantial downward bias in the estimation arose with homogeneous reporting and attack rates exceeding 50%. Mild heterogeneities in reporting ratios between vaccinated and unvaccinated strongly biased VE estimates, downward if cases in vaccinated were more likely to be reported and upward otherwise, particularly when taking as reference unvaccinated individuals.

Conclusions: In observational studies, high attack rates or differences in underreporting between vaccinated and unvaccinated may result in biased VE estimates. This study underscores the critical importance of monitoring data quality and understanding biases in observational studies, to more adequately inform public health decisions.

低报感染对回顾性队列研究得出的疫苗有效性估计值的影响。
背景:监测数据和疫苗接种登记被广泛用于提供实时的疫苗有效性(VE)估计值,但由于感染报告不足(即确定和通知不足),这些估计值可能存在偏差。在此,我们研究了在不同情况下,包括不同程度的漏报、已接种疫苗和未接种疫苗者之间漏报的异质性以及不同程度的病原体循环等,回顾性队列研究中这一偏倚来源的程度和方向如何变化:我们建立了一个基于个体的随机模型,模拟呼吸道病毒的传播动态和大规模疫苗接种活动。考虑到年发病率为 22.5%、报告率为 30% 的基线情景,我们探讨了 14 种备选情景,每种情景都修改了一个或多个基线假设。利用模型生成的合成个体级监控数据和疫苗接种登记,我们以未接种疫苗或近期接种疫苗的个体(接种后 14 天内)为参照,估算了记录在案的感染 VE。通过将估算值与模型中假设的已知VE进行比较,对偏差进行量化:结果:假定报告比率相同,即使在低水平(10%)和中等发病率(结论:在观察性研究中,高发病率和低报告比率会导致VE估计值的偏差:在观察性研究中,高发病率或接种疫苗与未接种疫苗之间的漏报差异可能会导致 VE 估计值出现偏差。这项研究强调,监测数据质量和了解观察性研究中的偏差至关重要,以便为公共卫生决策提供更充分的信息。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
International journal of epidemiology
International journal of epidemiology 医学-公共卫生、环境卫生与职业卫生
CiteScore
13.60
自引率
2.60%
发文量
226
审稿时长
3 months
期刊介绍: The International Journal of Epidemiology is a vital resource for individuals seeking to stay updated on the latest advancements and emerging trends in the field of epidemiology worldwide. The journal fosters communication among researchers, educators, and practitioners involved in the study, teaching, and application of epidemiology pertaining to both communicable and non-communicable diseases. It also includes research on health services and medical care. Furthermore, the journal presents new methodologies in epidemiology and statistics, catering to professionals working in social and preventive medicine. Published six times a year, the International Journal of Epidemiology provides a comprehensive platform for the analysis of data. Overall, this journal is an indispensable tool for staying informed and connected within the dynamic realm of epidemiology.
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