甲型H1N1流行性感冒56例流行病学和临床学分析

Analysis of epidemiological and clinical characteristics of 56 confirmed cases of influenza A （H1N1）

目的了解学校甲型H1N1流行性感冒（流感）暴发的流行病学和临床特征。方法将56例确诊患者的流行病学调查和临床资料录入EPIDATA数据库，采用STATA软件分析其流行病学和临床学特点，采用RT—PCR法进行甲型H1N1流感病毒核酸检测。率的比较采用x^2检验，多个样本均数的比较采用单因素方差分析。结果50例患者为同一小学学生，5例为密切接触者，发病高峰为2009年6月18日和19日。患者从发病至就诊、发病至入院、病程及住院时间的中位数分别为0、2、6和7d。主要临床表现为发热56例、咳嗽54例、咳痰31例、扁桃体肿大25例和咽痛18例。合并症的发生率为10．7％（6例），主要为急性支气管炎。患者在发病后7d之内、发病8～10d及10d以上咽拭子甲型H1N1流感病毒核酸阳性率分别为74．39％、5．13％和0，差异有统计学意义（x^2=95．0412，P〈0．01）。单用奥司他韦治疗，奥司他韦联合中药治疗及单用中药治疗患者的病程分别为8．88、9．31和10d，差异无统计学意义（F=0．37，P=0．6927）。17例有可疑接触史患者的平均潜伏期为1d。结论甲型H1N1流感病情温和，其流行病学和临床表现与普通季节性流感类似。建议将甲型H1N1流感传染期判断标准调整为患者自出现症状前1d至发病后10d。

Objective To understand epidemiological and clinical characteristics of 56 cases of influenza A （H1N1） related to an outbreak in school Methods The epidemiological and clinical data of 56 cases of influenza A （H1N1 ） were input in EPIDATA and analysis of epidemiological and clinical characteristics was conducted by STATA. Reverse transcription polymerase chain reaction （RT-PCR） was used to test nucleic acid of influenza A （H1N1） virus. Comparison between rates was done by chi square tests. Comparison of means of multiple samples was done by one-factor analysis of variance. Results Fifty patients were in the same primary school. Five patients were close contacts. The peak time of incidence was from June 18th to 19th, 2009. Median periods from illness onset to visiting doctors, from illness onset to hospitalization, course of disease and hospitalization were 0, 2, 6 and 7 days, respectively, and the most frequently reported symptoms were fever （56/56 cases, 100%）, cough （54/56 cases, 96.4%）, expectoration （31/56 cases, 55.4%）, swelling of tonsil （25/56 cases, 44.6%） and sore throat （18/56 cases, 32.1%）. The incidence rate of complications was 10.7% and the main complication was acute bronchitis. The positive rates of nucleic acid of influenza A （H1N1） virus of throat swabs collected in 7 day after illness onset, from 8 to 10 days and after 10 days were 74.39%, 5.13% and 0, respectively, and the differences were statistically significant （x^2 =95. 0412, P〈 0. 01）. The median courses of disease for people who were treated with oseltamivir only, for people treated with oseltamivir and traditional medicine and for those treated with traditional medicine only were 8.88, 9.31 and 10 days, respectively, and no significant differences were found （F=0.37, P=0. 6927）. Median incubation period of 17 cases who had contact history was 1 day. Conclusions It seems that influenza A （HIN1） is mild and its epidemiological and clinical features are similar to those of seasonal influenza. It is suggested that the infective course of influenza A （H1N1） be revised to be from 1 day before illness onset to 10 days after that.