Analysis shows there might be two subtypes from the very early days: https://academic.oup.com/nsr/advance-article/doi/10.1093/nsr...

If the theory is correct, the L type is more aggressive and may be causing explosive outbreaks as in Wuhan, while the S type is less aggressive but harder to block from transmission. Interestingly, the S type is the ancestor. It would be interesting to see what is more prevalent in the outbreaks of South Korea, Italy and Iran.