Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China.
Lancet. 2013 Jul 13;382(9887):138-45. doi: 10.1016/S0140-6736(13)61207-6. Epub 2013 Jun 24.
Characterisation of the severity profile of human infections with influenza viruses of animal origin is a part of pandemic risk assessment, and an important part of the assessment of disease epidemiology. Our objective was to assess the clinical severity of human infections with avian influenza A H7N9 virus, which emerged in China in early 2013.
We obtained information about laboratory-confirmed cases of avian influenza A H7N9 virus infection reported as of May 28, 2013, from an integrated database built by the Chinese Center for Disease Control and Prevention. We estimated the risk of fatality, mechanical ventilation, and admission to the intensive care unit for patients who required hospital admission for medical reasons. We also used information about laboratory-confirmed cases detected through sentinel influenza-like illness surveillance to estimate the symptomatic case fatality risk.
Of 123 patients with laboratory-confirmed avian influenza A H7N9 virus infection who were admitted to hospital, 37 (30%) had died and 69 (56%) had recovered by May 28, 2013. After we accounted for incomplete data for 17 patients who were still in hospital, we estimated the fatality risk for all ages to be 36% (95% CI 26-45) on admission to hospital. Risks of mechanical ventilation or fatality (69%, 95% CI 60-77) and of admission to an intensive care unit, mechanical ventilation, or fatality (83%, 76-90) were high. With assumptions about coverage of the sentinel surveillance network and health-care-seeking behaviour for patients with influenza-like illness associated with influenza A H7N9 virus infection, and pro-rata extrapolation, we estimated that the symptomatic case fatality risk could be between 160 (63-460) and 2800 (1000-9400) per 100,000 symptomatic cases.
Human infections with avian influenza A H7N9 virus seem to be less serious than has been previously reported. Many mild cases might already have occurred. Continued vigilance and sustained intensive control efforts are needed to minimise the risk of human infection.
Chinese Ministry of Science and Technology; Research Fund for the Control of Infectious Disease; Hong Kong University Grants Committee; China-US Collaborative Program on Emerging and Re-emerging Infectious Diseases; Harvard Center for Communicable Disease Dynamics; US National Institute of Allergy and Infectious Disease; and the US National Institutes of Health.
对动物源流感病毒所致人类感染严重性的特征描述是大流行风险评估的一部分，也是疾病流行病学评估的重要组成部分。我们的目的是评估在中国 2013 年初出现的甲型 H7N9 禽流感病毒所致人类感染的临床严重程度。
截至 2013 年 5 月 28 日，我们从中国疾病预防控制中心建立的综合数据库中获取了关于实验室确诊的人感染甲型 H7N9 禽流感病毒病例的信息。我们评估了需要住院治疗的患者的病死率、机械通气风险和入住重症监护病房的风险。我们还利用哨点流感样疾病监测中发现的实验室确诊病例的信息来估计有症状病例的病死率风险。
在 123 例实验室确诊的甲型 H7N9 禽流感病毒感染住院患者中，截至 2013 年 5 月 28 日，37 例（30%）死亡，69 例（56%）已康复。在考虑到仍在住院的 17 例患者数据不完整后，我们估计所有年龄组患者的入院病死率为 36%（95%CI 26-45）。机械通气或死亡的风险（69%，95%CI 60-77）和入住重症监护病房、机械通气或死亡的风险（83%，76-90）均较高。基于对哨点监测网络的覆盖范围以及甲型 H7N9 禽流感病毒感染流感样疾病患者的就医行为的假设，并按比例外推，我们估计有症状病例的病死率可能在 160（63-460）和 2800（1000-9400）/100000 之间。
人感染甲型 H7N9 禽流感病毒似乎不如之前报道的那么严重。可能已经发生了许多轻症病例。需要继续保持警惕并持续强化控制措施，以尽量降低人类感染的风险。
中国科技部；传染病控制研究基金；香港大学教育资助委员会；中美新发与再发传染病合作项目；哈佛传染病动力学中心；美国国立过敏和传染病研究所；美国国立卫生研究院。
