Occurrence of invasive pneumococcal disease and number of excess cases due to influenza
Occurrence of invasive pneumococcal disease and number of excess cases due to influenza
复制标题
DOI：
10.1186/1471-2334-6-58
复制
发表时间：
2006-03-20
影响因子：
3.7
通讯作者：
Ekdahl, Karl
中科院分区：
文献类型：
--
作者：
Grabowska, Katarzyna;Hogberg, Liselotte;Ekdahl, Karl
背景：流感的特点是季节性暴发，通常具有高发病率和死亡率。它也被认为是大量继发性细菌感染的原因。肺炎链球菌是流感后继发性细菌性肺炎的主要病原体，流感可参与获得侵袭性肺炎球菌病（IPD）。方法：本研究旨在通过估计每年因流感引起的IPD病例数，探讨流感与IPD之间的关系。为此目的，我们使用流感期作为流感活动的指标，作为随后分析的风险因素。在两种模式下进行了统计建模。首先，我们构建了两个负二项回归模型。对于每个模型，我们估计了流感在模型中的贡献，并计算了IPD病例的超额数量。此外，对于每个模型，我们研究了流感和IPD之间的几个滞后时间。其次，我们构建了一个“无流感”基线，并计算IPD数据（观察病例）和基线（预期病例）的差异，以估计每年因流感引起的IPD病例的额外数量。这两种模式都是用零到四周的滞后时间来计算的。结果：分析显示流感引起的IPD病例每年增加72 ~ 118例，相当于每年增加6 ~ 10%或每个流感季节增加12 ~ 20%。此外，一至三周的滞后时间似乎在IPD与流感之间的关系中具有重要意义。结论：本流行病学研究证实流感与IPD之间存在关联。此外，负二项回归模型可用于计算与流感相关的IPD超额病例数。
Background: Influenza is characterized by seasonal outbreaks, often with a high rate of morbidity and mortality. It is also known to be a cause of significant amount secondary bacterial infections. Streptococcus pneumoniae is the main pathogen causing secondary bacterial pneumonia after influenza and subsequently, influenza could participate in acquiring Invasive Pneumococcal Disease (IPD).Methods: In this study, we aim to investigate the relation between influenza and IPD by estimating the yearly excess of IPD cases due to influenza. For this purpose, we use influenza periods as an indicator for influenza activity as a risk factor in subsequent analysis. The statistical modeling has been made in two modes. First, we constructed two negative binomial regression models. For each model, we estimated the contribution of influenza in the models, and calculated number of excess number of IPD cases. Also, for each model, we investigated several lag time periods between influenza and IPD. Secondly, we constructed an "influenza free" baseline, and calculated differences in IPD data ( observed cases) and baseline ( expected cases), in order to estimate a yearly additional number of IPD cases due to influenza. Both modes were calculated using zero to four weeks lag time.Results: The analysis shows a yearly increase of 72 - 118 IPD cases due to influenza, which corresponds to 6 - 10% per year or 12 - 20% per influenza season. Also, a lag time of one to three weeks appears to be of significant importance in the relation between IPD and influenza.Conclusion: This epidemiological study confirms the association between influenza and IPD. Furthermore, negative binomial regression models can be used to calculate number of excess cases of IPD, related to influenza.