论文标题
先前的低率菌株大流行，可诱导对COVID-19的免疫力
A preceding low-virulence strain pandemic inducing immunity against COVID-19
论文作者
论文摘要
预计来自中国传通流量的国家预计将处于COVID-19-19的风险最高。但是，COVID-19病例数（感染水平）与传入的交通级别负相关。此外，感染水平与种群大小呈正相关，而后者只能在达到畜群免疫力后影响感染水平。如果低病毒菌株（LVS）在几个月前从中国开始扩散，从而从后来新出现的已知SARS-COV-2高病毒菌株（HVS）提供免疫力，则可以解释这些。我们发现Covid-19大流行的动力学取决于LVS和HVS扩散两倍的时间以及其初始on术之间的延迟。我们发现，LVS倍增时间为$ t_l \ sim1.59 \ pm0.17 $ $倍（$ t_h $）慢（$ t_h $），但其较早的发作允许其全球广泛扩展到牛群免疫所需的水平。在较早暴露于LVS和/或人口较小的国家中，LV较早地实现了牛群免疫力，从而减少了HVS传播的时间，并提高了HVS感染水平较低。这样的模型准确地预测了一个国家的感染级别（{\ rm rm r^{2} = 0.74}; {\ rm 5.2 \ rm 5.2 \ times10^{ - 13}}的p值仅给出了中国的总体大小和输入的 - 来自中国的人口大小。它解释了与传入交通（$ c_ {exp} $）的负相关性，与人口大小（n_ {pop}）及其特定关系的正相关（$ {\ rm n} _ {\ rm case} _ {\ rm case} \ propto n_ {pop} t_ {h}}}}} \ times c_ {exp}^{{\ rm t_ {l}/{\ rm t_ {h} {h} -1}}}} $）。我们发现，大多数国家应该已经实现了牛群免疫力。在这些国家，进一步的COVID-19-Sprech受到限制，预计不会增加2-3倍。我们建议进行测试/预测，以进一步验证模型并在生物学上识别LV，并讨论含义。
Countries highly exposed to incoming traffic from China were expected to be at the highest risk of COVID-19 spread. However, COVID-19 case numbers (infection levels) are negatively correlated with incoming traffic-level. Moreover, infection levels are positively correlated with population-size, while the latter should only affect infection-level once herd immunity is reached. These could be explained if a low-virulence strain (LVS) began spreading a few months earlier from China, providing immunity from the later emerging known SARS-CoV-2 high-virulence strain (HVS). We find that the dynamics of the COVID-19 pandemic depend on the LVS and HVS spread doubling-times and the delay between their initial onsets. We find that LVS doubling-time to be $T_L\sim1.59\pm0.17$ times slower than the HVS ($T_H$), but its earlier onset allowed its global wide-spread to the levels required for herd-immunity. In countries exposed earlier to the LVS and/or having smaller population-size, the LVS achieved herd-immunity earlier, allowing less time for the spread of the HVS, and giving rise to lower HVS-infection levels. Such model accurately predicts a country's infection-level ({\rm R^{2}=0.74}; p-value of {\rm 5.2\times10^{-13}}), given only its population-size and incoming-traffic from China. It explains the negative correlation with incoming-traffic ($c_{exp}$), the positive correlation with the population size (n_{pop}) and their specific relations (${\rm N}_{\rm cases}\propto n_{pop}^{{\rm T_{L}/{\rm T_{H}}}}\times c_{exp}^{{\rm T_{L}/{\rm T_{H}-1}}}$). We find that most countries should have already achieved herd-immunity. Further COVID-19-spread in these countries is limited and is not expected to rise by more than a factor of 2-3. We suggest tests/predictions to further verify the model and biologically identify the LVS, and discuss the implications.
