"在所有無症狀陽性的人身上都沒發現活病毒"算不上新發現

"在所有無症狀陽性的人身上都沒發現活病毒"算不上新發現

科普閑談

2020年11月28日

今年七月的一篇論文【1】就報道：小孩體內病毒基因片段的密度是成年人的十倍左右。大家知道，小孩出症狀率低，傳染率低，病亡率也很低。有篇報道【2】給出更詳細的結果，細節如下：

Box 1: Data on COVID-19 in Children in the United States

Children, under the age of 18, to date, account for:   7% (more than 200,000) of reported COVID-19 cases* (source CDC) <1% of reported COVID-19 deaths* (source: CDC) 1% of reported COVID-19 hospitalizations (source: CDC) The number of reported cases of Multisystem Inflammatory Syndrome in Children (MIS-C) is 342, including 6 deaths, among states reporting data (source: CDC) *Based only on data for which age group information was available.

中國學者的論文中【3】， 有一段陳述也指出了這種現象：

“The 300 asymptomatic positive persons aged from 10 to 89 years, included 132 males (0.256/10,000) and 168 females (0.355/10,000). The asymptomatic positive rate was the lowest in children or adolescents aged 17 and below (0.124/10,000), and the highest among the elderly aged 60 years and above (0.442/10,000) (Table 1). The asymptomatic positive rate in females (0.355/10,000) was higher than that in males (0.256/10,000).”

要特別注意的是，文中【3】指出無症狀陽性的病人中有168個是女性。新冠病毒在女性體內找不到讓自己變強和複製增長的最佳資源，一般來說是難以持續的；女性病患的病因與男性完全不同，不能一視同仁。

簡單地慨括一下， 無症狀陽性病人內的病毒， 要麽是死的，要麽是處於很弱的狀態。這與常理相符。哪有新冠病毒這種惡性病源在體內大量聚集而症狀輕微或無毫無症狀的道理？

【1】Taylor Heald-Sarget, et al., "Age-Related Differences in Nasopharyngeal Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Levels in Patients With Mild to Moderate Coronavirus Disease 2019 (COVID-19)", JAMA Pediatrics. July 30, 2020. 

【2】Josh Michaud & Jennifer Kates, "What Do We Know About Children and Coronavirus Transmission?", KFF. July 24, 2020.

【3】shiyi Cao, et al., "Post-lockdown SARS-CoV-2 nucleic acid screening in nearly ten million residents of Wuhan, China", Nature Communications. November 20, 2020.