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新型冠狀病毒疫情系列之 14 — 數據及歐陸小國

2020/4/13 — 17:11

資料圖片,來源:Martin Sanchez @ Unsplash

資料圖片,來源:Martin Sanchez @ Unsplash

今天最搶眼球的一篇學術論文是一位德國大學教授引用醫學權威期刊《柳葉刀》上的數據所寫的一篇文章。他說,我們現在所確診的病例只及實際的6%。他的文章再一次引起人們對無病癥患者散播病毒的恐懼。(註1)

但他是研究印度的學者,其文章不能達到《柳葉刀》對文章要求的水平。他在報告中認為西班牙的實際受感染者為全國人口的12.24%。西班牙人口為4千6百萬,現確診人數為16萬,即人口的0.3%,與12.24%相距甚遠。

根據歐盟資料,三分之一的確診者需要入院,入院者的死亡率達一成。香港在疫症早期約有2個月沒有封關,兩地來往頻繁,普遍地戴口罩也是稍後的事,若以這篇文章所說的只測到約6%帶菌者的說法,那段時間這批龐大的帶菌者應感染他們的緊密接觸者,以50%論也應有6份之1的入院者。這解釋不到香港確診者人數之低。

廣告

要找出隱性患者的比例,只有抗體測試才能做到。到目前為止,無論在全球,還是在西方資訊開放的地方,抗體測試已有大量數據。從統計學上,我們不需要找一個小國進行全民測試才能找出隱性患者比例,只要數據足夠大量,就能推算出隱性患者或尚受感染者的比例,只是沒有一個國家公佈數據或沒有一個醫學機構進行研究。

無論如何,西方各國都準備對其國民進行大規模抗體測試,目前只等待足夠的合資格試劑產品,預計在一個月之內可以證明這位德國學者的預測是否合理。英國也曾希望採購3百50萬份抗體測試套件,但英國的衛生大臣在4月3日承認,他找不到符合要求的產品。(註2)

廣告

另一個搶眼球的是劍橋大學4/9/2020發表的論文,認為新冠病毒A類是病毒爆發的根源,而A類集中出現在美國和澳洲,出現於武漢的病毒屬於B類,是從A類變異而來。(註3)

這裡所指的病毒基因變異不是一般人理解的基因變異。它是指一些很微少的變異,大概可理解為基因指模,足以分辨出這堆病毒來自那一地區。它的變異不足以改變其攻擊人體細胞的方法,亦即,假如我們研制出一種疫苗,這疫苗可針對現有的新型冠狀病毒有效。

歐洲小國

現在媒體最關注的是美國和英國的疫情,但以人口比例計,歐洲的一些小國的數字更嚴重,它們的發展對香港更有啟示。

以平均一百萬人口計的死亡人數,西班牙為355人;意大利322;比利時289;法國212,荷蘭154;英國145;瑞士120;盧森堡99;美國62。

以受確診人均值計,盧森堡排行極高為5224;西班牙為3487;意大利2518;比利時2418;美國1611;荷蘭1425。(註4)

盧森堡

盧森堡人口為61萬,它在4月11日有60人因疫症死亡,受感染為3300人,疫情正不斷上升,它的總理表示,準備在4月20日決定是否結束封城措施,恢復商業活動。它的衛生大臣表示,很有可能解封。這可能成為一個在疫情未穩定下解封的重要參考案例。 (註5)

比利時

比利時人口為1千1百萬,它在4月12日的死亡人數為3346,確診人數為20,018。從《紐約時報》的圖表看,以25個死亡個案作計算開始,它進入了約第25個疫情日子,它的死亡人數約5天增加一倍,據它們的專家表示,疫情已進入高峰期(即平頂)。它只准許巿民出外購買食物、藥物和若不能家居工作而外出工作。它的專家表示不能簡單地比較不同國家的疫情,各國進入疫情的時間有先後,這可能帶來不同,他們認為死亡數目是較重要的比較指標。

比利時有研究指出,人們在戶外的跑步運動可能帶來一條長達15米的帶病毒氣流,引起感染。(註6)

荷蘭

荷蘭人口為1千7百萬,它在4月12日的死亡人數為2643,確診人數為24,413,它約進入第24個疫情日子,死亡人數每8天增加一倍。荷蘭的疫情發展較樂觀,它已錄得連續十天的疫情減弱。

荷蘭表示,進入深切治療室的倖存者可能在未來的數年內產生心理障礙,它準備進行一個涉及數千人的研究計劃和支援這批疫症倖存者。(註7)

討論

新型冠狀病毒疫情歸根究底是一科學問題,對其了解需要專家意見。但這裡有三個問題。一,某一教授寫一篇文章未必是專家意見;二,醫生習慣性地將問題說到最大或模棱两可;三,就算受過大學教育的也可能將專家意見混淆。

香港受疫情影響大約與武漢的一月份始,至今的受感染人數和死亡人數都相對很低,它在未來的日子裏會否發展到如比利時、荷蘭、盧森堡模式未可知。

另外一些地方,如星加坡、馬來西亞,它們的數字也頗低,但這些地方已開始封城,嚴陣以待。這可能是看了美國例子,前車可鑑,擔心疫情發展太快。

在五月,歐洲各國、英國、美國的疫情都過了三個月的發展期,和抗體測試可望全面普及,人們或會對這疫情的發展有更多的了解。

備註

註1

COVID-19: on average only 6% of actual SARS-CoV-2 infections detected worldwide

A recent study,2 combining data from mainland China with those of international Wuhan residents returning on repatriation flights, presented novel age-specific estimates for the infection fatality rate

https://www.ft.com/content/e00120a2-74cd-11ea-ad98-044200cb277f

Rapid risk assessment: Coronavirus disease 2019 (COVID-19) pandemic: increased transmission in the EU/EEA and the UK – eighth update

Risk assessment

8 Apr 2020

Based on data from EU/EEA countries, 32% of the diagnosed cases have required hospitalisation and 2.4% have had severe illness requiring respiratory support and/or ventilation. The crude fatality rate was 1.5% among diagnosed cases and 11% among hospitalised cases. The likelihood of hospitalisation, severe illness and death increases in persons over 65 years of age and those with defined risk factors including hypertension, diabetes, cardiovascular disease, chronic respiratory disease, compromised immune status, cancer and obesity

註2

Britain’s coronavirus testing scandal: a timeline of mixed messages

3 April: 100,000 target clarified

Hancock tells broadcasters that the prime minister’s 25 March commitment to get to 250,000 tests a day “still stands”, but that he wanted to “put a very clear timeline” on the goal to get to 100,000 by the end of the month. He says it is “frustrating” that the first antibody tests have not worked. The prime minister’s spokesman is forced to clarify that the 100,000 target is for England only.

Blow to getting Britain back to work after Oxford scientist tasked with evaluating crucial coronavirus antibody tests says it may take a MONTH before one is ready for Britain to use as another expert warns the kits may only be 50% accurate

According to FDA paperwork the test is 93.8 per cent accurate at detecting positive cases of the virus.

https://www.independent.co.uk/life-style/health-and-families/coronavirus-antibody-test-what-is-it-virus-blood-nhs-matt-hancock-covid-19-a9423571.html

註3

COVID-19: genetic network analysis provides ‘snapshot’ of pandemic origins

註4

https://www.worldometers.info/coronavirus/?#countries

註5

Luxembourg

https://www.worldometers.info/coronavirus/country/luxembourg/

Luxembourg's health ministry says more than 60 dead, nearly 3300 infected

Hospitals were treating 210 sufferers of Covid-19, with 33 of those in intensive care. Another 444 patients have been discharged after being treated in hospitals, the health ministry said

Plans for ending lockdown coming soon, health minister says

Luxembourg to decide lockdown exit plan by 20 April

Government to decide how to restart business activity as infections stabilise.

註6

https://www.worldometers.info/coronavirus/country/belgium/

https://www.nytimes.com/interactive/2020/03/21/upshot/coronavirus-deaths-by-country.html?algo=top_conversion&fellback=false&imp_id=566382471&imp_id=281643202&action=click&module=Most%20Popular&pgtype=Homepage

Expert: Belgium approaching coronavirus peak

08.04.2020

Coronavirus expert warns against comparing countries Saturday, 11 April 2020

“We believe the best way to compare is to take the number of hospital deaths, which is 1,840 in Belgium.

23 days , doubling every 5 days

Outdoor activities require stricter social distancing, Belgian study suggests

Wednesday, 08 April 2020

While slipstreams can sometimes be as long as 10 to 15 metres, Blocken said that they remained quite narrow and noted that respiratory droplets tended to evaporate quite quickly.

註7

https://www.nytimes.com/interactive/2020/03/21/upshot/coronavirus-deaths-by-country.html?algo=top_conversion&fellback=false&imp_id=566382471&imp_id=281643202&action=click&module=Most%20Popular&pgtype=Homepage

Ten straight drops in Covid-19 hospitalizations; Coronavirus deaths near 2,650

LARGE MAJORITY OF ICU PATIENTS SUFFER LONG-TERM CONSEQUENCES FROM VISIT

By Byron Mühlberg on April 11, 2020 - 11:16

According to the results so far, seven out of 10 ICU patients experience "moderate to severe negative consequences" for as much as a year after they had first been admitted to intensive care, in a phenomenon the researchers coined 'Post Intensive Care Syndrome', or PICS. Patients reported feelings of "fear and gloom", trouble with their memory and concentration, as well as the processing of stimuli (i.e. how they respond when many things occur at once).

There were 1,384 Covid-19 patients from the Netherlands requiring ICU care as of Friday evening.

Total case  24,413  death 2,643         25days, doubling every 8 days

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