Since its first detection in the UK in September 2020, a highly contagious version of the coronavirus, the alpha or British variant a.k.a. B.1.1.7 SARS-CoV-2 virus lineage, rapidly spread across several countries and became the dominant strain in the outbreak.

Here it is shown that a very simple evolutionary model can fit the observed change in frequency of B.1.1.7 for several countries, regions of countries and the whole world with a single parameter, its relative fitness f, which is almost universal f ≈ 1.5. This is consistent with a 50% higher transmissibility than the local wild type and with the fact that the period in which this variant takes over has been in all the studied cases around 22 weeks.

自 2020 年 9 月在英国首次发现以来，一种高度传染性的冠状病毒版本，即 alpha 或英国变种，又名 B.1.1.7 SARS-CoV-2 病毒谱系，迅速传播到多个国家，并成为该病毒的主要毒株暴发。

这里表明，一个非常简单的进化模型可以用一个参数拟合观察到的几个国家、国家地区和整个世界的 B.1.1.7 频率变化，它的相对适应度f，几乎是普遍的f ≈ 1.5. 这与比本地野生型高 50% 的传播率以及在所有研究案例中该变体接管的时间约为 22 周这一事实是一致的。