Abstract: Background　Influenza is a common acute respiratory disease with a high incidence，which often affects the quality of life，and may result in serious complications and may even lead to death.So monitoring and analyzing influenza are essential for the prevention and control of this disease.Objective　To explore the incidence and trend of influenza in China from 2005 to 2015 by region，sex and age group，and to determine the developmental trajectory of subgroups.Methods　The research was developmented from February to November 2018.The data of incidence of influenza in China from 2005 to 2015 were obtained from the National Scientific Data Sharing Platform for Population and Health.Descriptive analysis was performed on the incidence of influenza by region，sex and age group，and annual growth rate during the period was calculated.The trajectory model was used to explore the number of subgroups and corresponding characteristics of different trajectories.Results　During this period，the annual incidence of influenza increased from 3.51% in 2005 to 14.37% in 2015，generally showing an upward trend.Males had a higher overall incidence than females.But the average annual growth rate was higher in females（15.93%） than that in males（14.51%）.And greater increase of incidence was found in the elderly aged 70-year-old and above（32.04%） and children below 5 years old（29.41%）.Three types of trajectories could be categorized for different trends of influenza.The first subgroup had the highest incidence with a general upward trend，gradually reaching a relatively steady state，in particular，the situation of prevention and control for people under 5 years old and 5-14 years old in Tianjin，Hebei，Shanghai，Fujian，Hubei，Hunan，Guangdong，Gansu and Ningxia is more severe.The second subgroup had a mid-level incidence and a continual increase，it is urgent to control its rising momentum. Shanxi and Henan are the areas that need to be focused on. The lowest incidence was found in the third subgroup，which increased slowly.Conclusion　The incidence of influenza in China from 2005 to 2015 had different trajectories.Identifying different trajectories of age-，gender-，and region-specific incidence of influenza is helpful for taking targeted measures for influenza prevention and control.

Key words: Influenza, human；Incidence；Change trend；Trajectory model

摘要： 背景　流行性感冒是常见的急性呼吸道传染病，发生率较高，影响生活质量，可导致严重的并发症甚至造成死亡，开展流行性感冒的监测分析研究，对于疾病防控具有重要的应用价值。目的　分析2005—2015年我国不同地区、性别、年龄段人群的流行性感冒发病率状况和变化趋势，并确定各亚组的发展轨迹。方法　于2018年2—11月开展研究。2005—2015年流行性感冒发病数据来源于公共卫生科学数据中心。描述2005—2015年中国不同地区、性别、年龄段人群的流行性感冒发生状况，计算2005—2015年流行性感冒发病率年平均增长速度，采用轨迹分析模型确定流行性感冒发病率的发展轨迹。结果　2005—2015年中国流行性感冒发病率大致呈上升趋势，流行性感冒总发病率从2005年的3.51%上升到2015年的14.37%。男性发病率整体高于女性，但女性发病率的年平均增长速度（15.93%）整体高于男性（14.51%），发病率上升幅度较大的为≥70岁人群（32.04%）和<5岁人群（29.41%）。2005—2015年我国流行性感冒发病率变化趋势存在3种不同发展轨迹，其中第1亚组流行性感冒发病率水平最高，呈稳步上升并逐渐趋于稳定状态，尤其是针对天津、河北、上海、福建、湖北、湖南、广东、甘肃、宁夏<5岁和5~14岁人群的防控形势较为严峻；第2亚组为中等发病率水平呈持续上升趋势，亟须控制其持续上升的势头，需要重点关注的地区是山西和河南；第3亚组发病率水平最低，并呈缓慢上升趋势。结论　2005—2015年我国流行性感冒发病率随年代变化的轨迹不同，识别不同地区、性别、年龄段人群各自的发展特点，有助于针对性地制定相应的流行性感冒防控措施。

关键词: 流感, 人；发病率；变化趋势；轨迹模型