余宏杰课题组在禽流感H7N9病毒人际间传播风险研
时间:2023-10-15 19:13 来源:网站管理员 作者:网站管理员 点击:次
复旦大学公共卫生学院余宏杰课题组在禽流感H7N9病毒人际间传播风险研究领域取得进展,研究结果以“Assessment of Human-to-Human Transmissibility of Avian Influenza A(H7N9) Virus Across 5 Waves by Analyzing Clusters of Case Patients in Mainland China, 2013–2017”为题于近期发表在 Clinical Infectious Diseases (IF 9.12)(论文链接:https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciy541/5046928)。 自2013年3月中国发现了全球首例人感染禽流感H7N9病例以来,每年冬春季都会出现一波人感染禽流感H7N9疫情。该病毒可通过基因重配或适应性突变演变成为引起流感大流行的病毒,持续的病毒学和流行病学研究是大流行风险评估的重要内容。 2016-2017年第五波疫情前,H7N9病毒为低致病性禽流感病毒。2017年初,有研究报道,少数人感染禽流感H7N9病例中所分离病毒的HA裂解位点插入了多个碱性氨基酸,提示该病毒已变异为高致病性禽流感病毒。2016-2017年第五波疫情较往年出现的早,地理扩散范围更广,报告的病例数也超过了前四波。因此,第五波疫情中,禽流感H7N9病毒在人与人之间的传播风险是否增强成为尚待解决的科学问题。 本研究通过分析聚集性H7N9疫情的流行病学参数的变化,定量评估H7N9病毒人际间的传播风险是否发生了变化。研究发现,报告的聚集性病例的发病时间分布与散发病例相似。聚集性H7N9疫情的中位病例数为2,最大为3。所有聚集性H7N9疫情的人际传播均未超过2代。与没有血缘关系的亲属相比,有血缘关系的感染禽流感H7N9的相对危险度为1.65(95%置信区间:0.88-3.09),但无统计学差异。假设具有相同的易感性,统计模拟的结果显示,当聚集性H7N9病例占全部病例5.6%时,暴露后人感染禽流感H7N9的风险为4.2%(图A)。禽流感H7N9病毒有效繁殖数上限为0.12(95%置信区间:0.10-0.14),各波次间无统计学差异(χ2 = 1.52, p=0.822)(图B)。 图:五波人感染禽流感H7N9疫情中,感染发病的风险及有效繁殖数上限估计值 (A:聚集性病例占比与感染风险;B:有效繁殖数上限估计值) 本研究表明,随着疫情进展,禽流感H7N9病毒的人际间传播风险并未发生明显变化。尽管第五波疫情中,人感染禽流感H7N9的地理扩散范围更广,报告病例数更多,但相对较小的聚集性疫情病例数和有效繁殖数均提示,第五波疫情中人传人的风险非常有限。本研究定量评估了禽流感H7N9病毒人际间传播风险的变化,为流感大流行的风险评估及防控策略的制定提供了科学证据。余宏杰教授为本文的通讯作者,王锡玲副教授为本文的第一作者。本研究得到国家自然基金委国家杰出青年科学基金项目(81525023)的资助。 Abstract Background The 2016–17 epidemic of human infections with avian influenza A(H7N9) virus was alarming, due to the surge in reported cases across a wide geographic area and the emergence of highly-pathogenic A(H7N9) viruses. Our study aimed to assess whether the human-to-human transmission risk of A(H7N9) virus has changed across the 5 waves since 2013. Methods Data on human cases and clusters of A(H7N9) virus infection were collected from the World Health Organization, open access national and provincial reports, informal online sources, and published literature. We compared the epidemiological characteristics of sporadic and cluster cases, estimated the relative risk (RR) of infection in blood relatives and non–blood relatives, and estimated the bounds on the effective reproductive number (Re) across waves from 2013 through September 2017. Results We identified 40 human clusters of A(H7N9) virus infection, with a median cluster size of 2 (range 2–3). The overall RR of infection in blood relatives versus non–blood relatives was 1.65 (95% confidence interval [CI]: 0.88, 3.09), and was not significantly different across waves (χ2 = 2.66, P = .617). The upper limit of Re for A(H7N9) virus was 0.12 (95% CI: 0.10, 0.14) and was not significantly different across waves (χ2 = 1.52, P = .822). Conclusions The small cluster size and low Re suggest that human-to-human transmissibility of A(H7N9) virus has not changed over time and remains limited to date. Continuous assessment of A(H7N9) virus infections and human case clusters is of crucial importance for public health. 来源:复旦大学公共卫生学院 本期编辑:Tony (责任编辑:admin) |