Earlier quoted context omitted.
COVID-19 is one of the few serious diseases that can transmit when the carrier is asymptomatic. That could be a credible reason why a potential lab leak went unnoticed for long enough to begin uncontrolled community spread.
> COVID-19 is one of the few serious diseases that can transmit when the carrier is asymptomatic. Is this actually true? It is certainly not true for HIV, and of course is not relevant to diseases like Zika that are transmitted by mosquitos. Edit: I found the answer to my own question: https://www.kff.org/infographic/ebola-characteristics-and-co... (see second bullet point). Given that this lists Hep C, HIV, Influenz…
You can catch flu from an asymptomatic person, but Covid has a much higher reproduction factor. During the winter lockdown in England, regular flu was completely eradicated - literally not a single case was detected in entire England [0]. At the same time, Covid was still spreading happily. The measures that stopped flu in its tracks only slightly inconvenienced SARS-Cov-2.
Covid is simply too good at spreading, compared to other similar diseases.
(As an analogy: I can swim, Michael Phelps can swim, we can both call ourselves swimmers, but we are not really comparable.)
[0]https://www.independent.co.uk/news/health/flu-cases-covid-en...