Table_1_The burden of hospital-attended influenza in Norwegian children.DOCX

BackgroundNorwegian health authorities do not recommend universal pediatric vaccination against seasonal influenza. We aimed to estimate the incidence of influenza by age and underlying medical conditions in hospitalized Norwegian children aged <18 years.
MethodsActive surveillance for influenza in children <18 years was implemented in five hospitals during 2015–18. Children with respiratory symptoms and/or fever were prospectively enrolled and tested for influenza. Surveillance data were linked to health registry data to estimate the national burden of influenza in hospitals.
ResultsIn 309 (10%) out of 3,010 hospital contacts, the child tested positive for influenza, corresponding to an average incidence of 0.96 hospital-attended influenza cases per 1,000 children <18 years of age. Children <1 year of age (3.8 per 1,000 children) and children with underlying medical conditions (17 per 1,000 children with bronchopulmonary dysplasia) had the highest average incidence. Among <1 year old children, 3% tested positive for influenza, compared to 25% for children aged 6–17. Few children were vaccinated against influenza.
ConclusionsChildren <1 year of age and children with underlying medical conditions had a higher incidence of influenza requiring hospital treatment compared to the general population. Effective interventions against seasonal influenza for children in Norway should be considered.

背景：挪威卫生当局不推荐对儿童普遍接种季节性流感疫苗。本研究旨在估算挪威18岁以下住院儿童中，按年龄和基础疾病分类的流感发病率。
方法：2015至2018年间，研究团队在五家医院开展针对18岁以下儿童的流感主动监测。对出现呼吸道症状和/或发热的儿童进行前瞻性入组，并开展流感病毒检测。将监测数据与健康登记数据相关联，以估算全国医院内流感的疾病负担。
结果：在3010次住院就诊中，共有309例（占比10%）儿童的流感检测结果呈阳性，对应每1000名18岁以下儿童中平均有0.96例因流感住院的病例。1岁以下儿童（每1000名儿童3.8例）以及合并基础疾病的儿童（如支气管肺发育不良患儿，每1000名患儿17例）的平均发病率最高。在1岁以下儿童中，流感检测阳性率为3%，而6至17岁儿童的阳性率达25%。接种流感疫苗的儿童占比极低。
结论：与普通人群相比，1岁以下儿童及存在基础疾病的儿童因流感需住院治疗的发病率更高。挪威应考虑针对儿童群体制定有效的季节性流感防控干预措施。