今年五月一日，yahoo news 出現一篇文章，由醫學記者報導WHO警告中國最近出現H7N9新禽流感，不僅症狀嚴重，致命率也很高。
(New bird flu poses "serious threat", scientists say http://news.yahoo.com/bird-flu-poses-serious-threat-scientists-213437969.html By Kate Kelland Reuters – Wed, May 1, 2013)
當時台灣已經派遣何美鄉及詹珮君兩位到上海訪視，四月初在自由時報頭版報告中國這些流行病中心計算死亡率的方法錯誤，以致死亡率會變得很高。(一定要參看自由時報這篇報導: http://tw.myblog.yahoo.com/ccshsu-clement/article?mid=10766&prev=10769&next=10764&l=a&fid=83)
因此筆者投書說: 中國不會計算死亡率，在台灣大大地報導，WHO專家似乎卻完全不知覺，質問為何這種攸關人命的國際流行病，台灣的新聞無人注意，是否因為台灣不是WHO一員之故?
到五月六日有一位 Dr. Eric Topol，是發佈這醫學新聞免費給訂閱者的Medscape 主編，回信給我。不過內容文不對題，似乎是說他不干此事。
五月二十二日，Medscape又報導H7N9有高死亡率，在下列網站。
(H7N9: Severe Illness, High Death Rate. by Troy Brown May 22, 2013 http://www.medscape.com/viewarticle/804596?nlid=31385_1661&src=wnl_edit_dail&uac=131220CK)
筆者於是再寫一次Comment (參看BLOG: http://tw.myblog.yahoo.com/ccshsu-clement/article?mid=10790&prev=11155&next=10767)，提出應該有人向中國衛生主管詢問他們如何計算死亡率。
到六月二十四日，Medscape又介紹一篇由北京CDC向 Lancet 報告的論文 (如下)，已經改變原來聲稱的高死亡率的說法。這篇是五月二十八日以前的感染數據分析。
其實他們這篇說新算出H7N9的死亡率37%，還是很高。不過問題不是在死亡率高不高，而是在於中國流行病相關醫院或中心，為何不知道如何計算死亡率? 為什麼台灣的報導無人注意?
不過，北京CDC的這篇文章很快就將五月二十八日以前的病例分析，在Lancet糾正前一篇報告的錯誤觀念，雖然他們沒有說明是如何糾正錯誤，哪一點錯誤，可是筆者相信台灣專家訪視，給予批評，是有正面的結果，致使他們趕快再報告一次，記者寫的標題是: "H7N9死亡率可能不如原來報導地高"。
(美國醫學記者的報導很精確、會指出重點，又常常會附加其他專家的評語，所以比原來的論文讀來更有趣。)
[http://www.medscape.com/viewarticle/806772?nlid=31843_1821&src=wnl_edit_dail&uac=131220CK]
H7N9 Fatality Rates May Be Lower Than Once Thought
Troy Brown
Jun 24, 2013
The case fatality risk for patients hospitalized with avian influenza A H7N9 virus may be lower than previously estimated, but the virus may reappear when the weather cools, according to data from researchers at the Chinese Center for Disease Control and Prevention (China CDC) in Beijing.
Hongjie Yu, MD, director of the Division of Infectious Disease, Key Laboratory of Surveillance and Early-Warning on Infectious Disease at the China CDC in Beijing, and colleagues present their findings in 2 articles published online June 24 in the Lancet.
In the first article, they used data as of May 28, 2013, from hospitalized patients with laboratory-confirmed H7N9 to estimate the risk for death, mechanical ventilation, and intensive care unit (ICU) admission. Sentinel influenza-like illness (ILI) surveillance data were used to estimate the symptomatic case fatality risk.
A total of 123 patients were hospitalized with laboratory-confirmed H7N9; of those, 37 (30%) died and 69 (56%) recovered. Of hospitalized patients, 71 (58%) were aged at least 60 years and 87 (71%) were men.
After accounting for incomplete data regarding 17 patients who were still hospitalized, the estimated fatality risk for all ages was 36% (95% confidence interval, 26% - 45%) on hospital admission.
Of the 108 patients for whom detailed clinical data were available, 71 (66%) required mechanical ventilation and 83 (75%) required ICU admission. The risks for ICU admission (P = .08) and mechanical ventilation (P = .0067) were higher for patients aged 60 years or older than for those who were younger.
Similarly, there were high risks for mechanical ventilation or fatality (69%; 95% CI, 60% - 77%), as well as ICU admission, mechanical ventilation, or fatality (83%; 95% CI, 76% - 90%) for all age groups, but the fatality risk was higher in those aged 60 years or older than for younger patients (P = .0019).
Using sentinel ILI data, the researchers estimated the symptomatic case fatality risk at between 160 (95% CI, 63 - 460) and 2800 (95% CI, 1000 - 9400) per 100,000 symptomatic cases. This estimate "suggests that avian influenza A H7N9 is not as severe as influenza A H5N1, but more severe than 2009 influenza A H1N1 pandemic virus," the authors write.
"[M]any mild cases might have occurred."
The median time to death for the 37 patients who died was 11 days (interquartile range, 6 - 23 days). The median time to recovery for the 69 patients who recovered was 18 days (interquartile range, 14 - 29 days).
H7N9 vs H5N1: Similarities and Differences
In the second paper, the same researchers compared the epidemiological characteristics of the H7N9 virus (130 patients reported to the China CDC before May 24, 2013) with those of the influenza A H5N1 virus (43 patients), which has been seen in China since 2003.
The median age was 62 years for those with H7N9 and 26 years for those with H5N1. "The differences in age distribution of patients with laboratory-confirmed infection with H7N9 and H5N1 are intriguing; presumably, immunity associated with different histories of influenza virus exposures has an important role in addition to differences in exposure patterns," the authors write.
For both viruses, 74% of patients in urban areas were men. In rural areas, the percentages of men with either virus were lower: 62% of H7N9 cases and 33% of H5N1 cases, respectively,. About three quarters of patients (75% of those with H7N9 and 71% of those with H5N1) reported recent poultry exposure.
"Whereas most patients with confirmed H7N9 and H5N1 infection reported exposure to live poultry, the type of exposure was very different in urban and rural locations...the male-to-female ratio is much higher in urban than in rural areas for both viruses," the authors write. "This result is consistent with sex-based differences in exposure, rather than differences in immunity."
The mean incubation period was 3.1 days for H7N9 and 3.3 days for H5N1. The average number of contacts that were traced for each case of H7N9 was 21 in urban areas and 18 in rural areas compared with 90 and 63 contacts, respectively, for H5N1.
On hospital admission, the fatality risk was 36% (95% CI, 26% - 45%) for H7N9 and 70% (95% CI, 56% - 83%) for H5N1.
"If H7N9 follows a similar pattern to H5N1, the epidemic could reappear in the autumn," the authors write. "This potential lull should be an opportunity for discussion of definitive preventive public health measures, optimisation of clinical management, and capacity building in the region in view of the possibility that H7N9 could spread beyond China's borders."
In an accompanying comment, Cécile Viboud, PhD, and Lone Simonsen, PhD, from the Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, Maryland, discuss the 2 articles. Dr. Simonsen is also from the Department of Global Health, School of Public Health and Health Services at George Washington University in Washington, DC.
"It is reassuring that head-to-head comparison of the fatality risk of admitted patients infected with avian influenza A H7N9 or H5N1 suggests a substantially milder disease course for H7N9," write Dr. Viboud and Dr. Simonsen. "Use of these estimates of case fatality risk to extrapolate the potential severity of a full pandemic would be tempting; however, whether global dissemination of these zoonotic influenza viruses would result in a catastrophic pandemic like that in 1918, or worse, or would mirror the mild 2009 pandemic is impossible to predict."
The first study was funded by the 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; National Institute of Allergy and Infectious Disease; and National Institutes of Health. The second study was funded by the Ministry of Science and Technology, China; Research Fund for the Control of Infectious Disease and University Grants Committee, Hong Kong Special Administrative Region, China; and National Institutes of Health. One coauthor has received research funding from MedImmune and consultant fees from Crucell NV. One coauthor has received speaker honoraria from HSBC and CLSA. The other authors have disclosed no relevant financial relationships. Dr. Simonsen is a member of the Severity Assessment Plan Technical Working Group initiated by the World Health Organization in 2013 and reports support from the RAPIDD program of the Science and Technology Directorate (US Department of Homeland Security). Dr. Viboud has disclosed no relevant financial relationships.
Medscape Medical News © 2013 WebMD, LLC
這篇原文在 Lancet 的摘要如下:
Human infection with avian influenza A H7N9 virus: an assessment of clinical severity
Hongjie Yua†Benjamin J Cowlinge†Luzhao Fenga†Eric HY LaueQiaohong LiaoaTim K TsangeZhibin PengaPeng WueFengfeng LiuaVicky J FangeHonglong ZhangaMing LiaLingjia ZengaZhen XuaZhongjie LiHuiming LuoQun LicZijian FengBin CaoWeizhong YangdJoseph T Wue Yu Wang Gabriel M Leung
Summary
Background
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.
Methods
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.
Findings
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.
Interpretation
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.
Funding
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.
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