Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
National Institute of Hygiene and Epidemiology, Hanoi, Vietnam.
Influenza Other Respir Viruses. 2019 May;13(3):248-261. doi: 10.1111/irv.12626. Epub 2019 Feb 28.
Influenza B is one of the major etiologies for acute respiratory infections (ARI) among children worldwide; however, its clinical-epidemiological information is limited. We aimed to investigate the hospitalization incidence and clinical-epidemiological characteristics of influenza B-associated paediatric ARIs in central Vietnam.
We collected clinical-epidemiological information and nasopharyngeal swabs from ARI children hospitalized at Khanh Hoa General Hospital, Nha Trang, Vietnam from February 2007 through June 2013. Nasopharyngeal samples were screened for 13 respiratory viruses using Multiplex-PCRs. Influenza B-confirmed cases were genotyped by Haemagglutinin gene sequencing. We analyzed the clinical-epidemiological characteristics of influenza B Lineages (Victoria/Yamagata) and WHO Groups.
In the pre-A/H1N1pdm09 period, influenza B-associated ARI hospitalization incidence among children under five was low, ranging between 14.7 and 80.7 per 100 000 population. The incidence increased to between 51.4 and 330 in the post-A/H1N1pdm09. Influenza B ARI cases were slightly older with milder symptoms. Both Victoria and Yamagata lineages were detected before the A/H1N1pdm09 outbreak; however, Victoria lineage became predominant in 2010-2013 (84% Victoria vs 16% Yamagata). Victoria and Yamagata lineages did not differ in demographic and clinical characteristics. In Victoria lineage, Group1 ARI cases were clinically more severe compared to Group5, presenting a greater proportion of wheeze, tachypnea, and lower respiratory tract infection.
The current results highlight the increased incidence of influenza B-related ARI hospitalization among children in central Vietnam in the post-A/H1N1pdm09 era. Furthermore, the difference in clinical severity between Victoria lineage Group1 and 5 implies the importance of influenza B genetic variation on clinical presentation.
乙型流感是全球儿童急性呼吸道感染（ARI）的主要病因之一；然而，其临床流行病学信息有限。我们旨在研究越南中部乙型流感相关儿童ARI 的住院发病率和临床流行病学特征。
我们收集了 2007 年 2 月至 2013 年 6 月在越南芽庄的庆和综合医院因 ARI 住院的儿童的临床流行病学信息和鼻咽拭子。使用多重 PCR 对鼻咽样本进行了 13 种呼吸道病毒的筛查。通过血凝素基因测序对乙型流感确诊病例进行了基因分型。我们分析了乙型流感谱系（维多利亚/山形）和世界卫生组织（WHO）组的临床流行病学特征。
在 A/H1N1pdm09 前时期，五岁以下儿童的乙型流感相关 ARI 住院发病率较低，范围为每 100000 人 14.7 至 80.7 例。在 A/H1N1pdm09 后，发病率增加到每 100000 人 51.4 至 330 例。乙型流感 ARI 病例年龄稍大，症状较轻。在 A/H1N1pdm09 爆发之前，检测到了维多利亚和山形两个谱系；然而，2010-2013 年，维多利亚谱系占主导地位（84%的维多利亚与 16%的山形）。维多利亚和山形谱系在人口统计学和临床特征上没有差异。在维多利亚谱系中，ARI 组 1 病例的临床症状比组 5 更严重，表现出更高比例的喘息、呼吸急促和下呼吸道感染。
目前的结果强调了 A/H1N1pdm09 后越南中部乙型流感相关 ARI 住院发病率的增加。此外，维多利亚谱系组 1 和组 5 之间临床严重程度的差异表明了流感 B 基因变异对临床表型的重要性。
