北京地区2014—2015年和2015年—2016年流感流行季儿童流感流行特征分析

Prevalence characteristics of influenza viruses in children in Beijing during 2014 -2015 and 2015 -2016 influenza- seasons

目的 比较分析北京地区2014—2015年和2015—2016年连续2个流感流行季中儿童流感的流行特征。方法 2014年9月（全年第36周）至2016年5月（全年第22周）每周采集首都儿科研究所附属儿童医院门、急诊流感样病例患儿的咽拭子标本，应用实时荧光反转录PCR方法进行甲型流感病毒、乙型流感病毒的核酸检测，同时对甲型流感病毒阳性标本进一步鉴别甲3型（H3N2）和甲1型（H1N1）流感病毒，对乙型流感病毒阳性标本进行B/Victoria（B/V）系和B/Yamagata（B/Y）系分型。采用描述性分析及t检验、χ^2检验对两个流感流行季的流行特征及各型别流感病毒感染患儿性别和年龄等特征进行比较分析。结果 2014年9月至2016年5月共采集流感样病例咽拭子标本1 821例，共检测到H3N2阳性标本139例（7.6%）；甲型H1N1阳性标本共43例（2.4%）；乙型流感病毒阳性标本共204例（11.2%），包括B/V系108例，B/Y系96例。甲型H1N1感染患儿年龄（3.3±2.2）岁，小于H3N2患儿组[（4.7±3.2）岁]和乙型患儿组[（4.9±2.8）岁]，差异有统计学意义（t＝2.848、3.682，P均〈0.05）。2014—2015年流行季，出现2个明显的流行峰，分别以H3N2和乙型流行峰（全部为B/Y系）为主要流行株；2015—2016年流行季，流感出现时间延后，起始于2015年第51周，整个流行季呈现H3N2、甲型H1N1和乙型共同流行的特点，乙型以B/V占绝对优势。结论 2014—2015年和2015—2016年2个流行季北京地区儿童中流感的流行呈现明显不同的流行特征。进入流感流行季应密切关注儿童中流感病毒的变异，包括乙型流感，及时为流感的防控提供科学依据。

Objective To compare the prevalence characteristics of influenza viruses in children in Beijing during 2014 -2015 and 2015 -2016 influenza seasons. Method Throat swabs were eolleeted weekly from children with influenza-like illnesses who visited in Children＇s Hospital affiliated to Capital Institute of Pediatrics during the period from September 2014 to May 2016. Influenza viruses A and B viruses were detected by real-time RT-PCR, followed by identification of H3N2, H1Nlpdm,B/Victoria-like and B/ Yamagata-like. The prevalence characteristics of influenza viruses was estimated by means of descriptive statistics. The t test and chi-square test were used to compare median age and gender ratio of infected children among different types of influenza viruses. Result Out of 1 821 throat swabs collected, 139 （7.6%） were positive for H3N2 and 43 （2.4%） for H1N1pdm and 204 （11.2% ） for influenza B virus, including 108 for B/Victoria-like and 96 for B/Yamagata-like. The median age of H1N1pdm infected children （ （ 3.3 ±2. 2 ） years ） was significantly younger than that of H3N2 （ （ 4. 7 ± 3.2 ） years ） and influenza B virus （ （4. 9 ± 2. 8） years） （ H1Nlpdm vs. H3N2： t = 2. 848, P = 0. 002; H1Nlpdm vs. influenza B, t = 3. 682, P = 0. 000）. Two epidemic peaks were presented in 2014 - 2015 influenza season, dominated definitely by H3N2 and B/Yamagata-like, respectively, while one delayed peak started at the 51 week, 2015, co-circulated with H3N2, H1 Nlpdm and influenza B vinases, among which B/Victoria-like virus was predominant during the 2015 -2016 season. Conclusion Prevalence characteristics of influenza viruses are different between 2014 - 2015 and 2015 - 2016 influenza seasonal epidemics in children in Beijing. It is important to monitor the genetic variations of influenza viruses and to keep close attention to influenza B virus as well as influenza A virus.