"在所有无症状阳性的人身上都没发现活病毒"算不上新发现

"在所有无症状阳性的人身上都没发现活病毒"算不上新发现

科普闲谈

2020年11月28日

今年七月的一篇论文【1】就报道：小孩体内病毒基因片段的密度是成年人的十倍左右。大家知道，小孩出症状率低，传染率低，病亡率也很低。有篇报道【2】给出更详细的结果，细节如下：

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.

中国学者的论文中【3】， 有一段陈述也指出了这种现象：

“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).”

要特别注意的是，文中【3】指出无症状阳性的病人中有168个是女性。新冠病毒在女性体内找不到让自己变强和复制增长的最佳资源，一般来说是难以持续的；女性病患的病因与男性完全不同，不能一视同仁。

简单地慨括一下， 无症状阳性病人内的病毒， 要么是死的，要么是处于很弱的状态。这与常理相符。哪有新冠病毒这种恶性病源在体内大量聚集而症状轻微或无毫无症状的道理？

【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.