Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Rio Grande do Sul, Brazil.
Laboratório Central de Saúde Pública, Centro Estadual de Vigilância em Saúde da Secretaria de Saúde do Estado do Rio Grande do Sul - LACEN/CEVS/SES-RS, Av. Ipiranga, Porto Alegre, Rio Grande do Sul, Brazil.
J Med Virol. 2021 Aug;93(8):4756-4762. doi: 10.1002/jmv.26822. Epub 2021 Feb 1.
Influenza B virus (IBV) causes respiratory tract infections with mild, moderate, or life-threatening symptoms. This study describes the epidemiology of IBV infection in Rio Grande do Sul (RS), Brazil, over 17 years. Nasopharyngeal samples were collected from outpatients presenting acute respiratory illness (ARI) between 2003 and 2019, and from inpatients with severe acute respiratory infection (SARI) from 2009 to 2019. IBV was detected by immunofluorescence assay or quantitative real-time polymerase chain reaction; demographic and clinical data were analyzed. In total, 48,656 cases of respiratory infection were analyzed, of which 20.45% were ARI, and 79.46% were SARI. Respiratory viruses accounted for 22.59% and 37.47% of the cases of ARI and SARI, respectively. Considering respiratory viral infections, 17.10% of ARI and 3.06% of SARI were associated with IBV. IBV circulated year-round in RS, with an increase in autumn and winter, peaking in July (p = .005). IBV infection showed an association with age, and most outpatients positive for IBV were between 10 and 49 years old, whereas IBV infection in SARI affected mainly individuals ≤ 1 year or ≥ 60 years old. No significant association was found between sex and IBV infection. Coryza, sore throat, and myalgia were associated with ARI (p < .001). Moreover, 3.18% of the deaths associated with respiratory virus infection were positive for IBV; notably, cardiopathy (p < .001), metabolic disease (p < .001), and smoking (p = .003) were associated to fatality in IBV infection. IBV is an important cause of severe respiratory infections, and the fatality risk is high in individuals with cardiopathy and metabolic diseases.
乙型流感病毒（IBV）可引起症状轻微、中等或危及生命的呼吸道感染。本研究描述了 17 年来巴西南里奥格兰德州（RS）IBV 感染的流行病学情况。2003 年至 2019 年间，从出现急性呼吸道疾病（ARI）的门诊患者和 2009 年至 2019 年间出现严重急性呼吸道感染（SARI）的住院患者中采集鼻咽样本。通过免疫荧光法或实时定量聚合酶链反应检测 IBV；分析人口统计学和临床数据。共分析了 48656 例呼吸道感染病例，其中 20.45%为 ARI，79.46%为 SARI。呼吸道病毒分别占 ARI 和 SARI 病例的 22.59%和 37.47%。考虑到呼吸道病毒感染，ARI 中有 17.10%和 SARI 中有 3.06%与 IBV 相关。IBV 在 RS 全年流行，秋冬季增加，7 月达到高峰（p = .005）。IBV 感染与年龄有关，大多数 IBV 阳性的门诊患者年龄在 10 至 49 岁之间，而 SARI 中的 IBV 感染主要影响 1 岁以下或 60 岁以上的个体。性别与 IBV 感染无显著相关性。鼻塞、咽痛和肌痛与 ARI 相关（p < .001）。此外，与呼吸道病毒感染相关的死亡病例中有 3.18%为 IBV 阳性；值得注意的是，心脏病（p < .001）、代谢性疾病（p < .001）和吸烟（p = .003）与 IBV 感染的病死率相关。IBV 是严重呼吸道感染的重要原因，心脏病和代谢性疾病患者的死亡风险较高。
