Hinds Aynslie M, Bozat-Emre Songul, Van Caeseele Paul, Mahmud Salaheddin M
Vaccine and Drug Evaluation Centre, Department of Community Health Sciences, Faculty of Health Sciences, University of Manitoba, S111 - 750 Bannatyne Avenue, Winnipeg, Manitoba, R3E 0W3, Canada.
Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
BMC Public Health. 2015 Jan 30;15:35. doi: 10.1186/s12889-015-1351-z.
Despite the public health significance of annual influenza outbreaks, the literature comparing the epidemiology of influenza A and B infections is limited and dated and may not reflect recent trends. In Canada, the relative contribution of influenza A and B to the burden of morbidity is not well understood. We examined rates of laboratory-confirmed cases of influenza A and B (LCI-A and LCI-B) in the Canadian province of Manitoba between 1993 and 2008 and compared cases of the two types in terms of socio-demographic and clinical characteristics.
Laboratory-confirmed cases of influenza A and B in Manitoba between 1993 and 2008 were identified from the Cadham Provincial Laboratory (CPL) Database and linked to de-identified provincial administrative health records. Crude and age-adjusted incidence rates of LCI-A and LCI-B were calculated. Demographic characteristics, health status, health service use, and vaccination history were compared by influenza type.
Over the study period, 1,404 of LCI-A and 445 cases of LCI-B were diagnosed, corresponding to an annual age-standardized rate of 7.2 (95% CI: 6.5-7.9) for LCI-A and 2.2 (CI: 1.5 - 3.0) per 100,000 person-years for LCI-B. Annual rates fluctuated widely but there was less variation in the LCI-B rates. For LCI-A, but not LCI-B, incidence was inversely related to household income. Older age, urban residence and past hospitalization were associated with increased detection of LCI-A whereas receipt of the influenza vaccine was associated with decreased LCI-A detection. Once socio-demographic variables were controlled, having a pre-existing chronic disease or immune suppression was not related to influenza type.
Influenza A and B affected different segments of the population. Older age was associated with increased LCI-A detection, but not with pre-existing chronic diseases. This information may be useful to public health professionals in planning and evaluating new and existing seasonal influenza vaccines.
尽管年度流感暴发具有公共卫生重要性，但比较甲型和乙型流感感染流行病学的文献有限且陈旧，可能无法反映近期趋势。在加拿大，甲型和乙型流感对发病负担的相对贡献尚不清楚。我们研究了1993年至2008年加拿大曼尼托巴省甲型和乙型流感实验室确诊病例（LCI - A和LCI - B）的发生率，并比较了这两种类型病例的社会人口统计学和临床特征。
从卡德姆省级实验室（CPL）数据库中识别出1993年至2008年曼尼托巴省甲型和乙型流感实验室确诊病例，并与去识别化的省级行政健康记录相链接。计算LCI - A和LCI - B的粗发病率和年龄调整发病率。按流感类型比较人口统计学特征、健康状况、医疗服务使用情况和疫苗接种史。
在研究期间，共诊断出1404例LCI - A病例和445例LCI - B病例，LCI - A的年龄标准化年发病率为每10万人年7.2（95%可信区间：6.5 - 7.9），LCI - B为2.2（可信区间：1.5 - 3.0）。年发病率波动很大，但LCI - B发病率的变化较小。对于LCI - A，而非LCI - B，发病率与家庭收入呈负相关。年龄较大、居住在城市和既往住院与LCI - A检测率增加相关，而接种流感疫苗与LCI - A检测率降低相关。一旦控制了社会人口统计学变量，既往存在慢性病或免疫抑制与流感类型无关。
甲型和乙型流感影响不同人群。年龄较大与LCI - A检测率增加相关，但与既往慢性病无关。这些信息可能有助于公共卫生专业人员规划和评估新的及现有的季节性流感疫苗。
