A coronavirus adapts for its host animal. It takes time to perfect itself for infecting humans. But a pathogen engineered via accelerated evolution in a laboratory using humanized mice would need no additional time after escape to optimize for human infection.
In their Nature Medicine paper, Mr. [Kristian] Andersen and colleagues pointed to what they considered the poor design of SARS-CoV-2 as evidence of zoonotic origin.
But a team of American scientists mutated the stem of the coronavirus genome in nearly 4,000 different ways and tested each variation. In the process they actually stumbled on the Delta variant.
In the end, they determined that the original SARS-CoV-2 pathogen was 99.5% optimized for human infection—strong confirmation of the lab-leak hypothesis.
Based on the scientific evidence alone, an unbiased jury would be convinced that SARS-CoV-2 coronavirus escaped after being created in a laboratory using accelerated evolution (a k a gain of function) and gene splicing on the backbone of a bat coronavirus.
Using standard statistical methods, we can quantify the likelihood of the lab-leak hypothesis compared with that of zoonosis. The odds enormously favor a lab leak, far more significantly than the 99% confidence usually required for a revolutionary scientific discovery.
