Two years of covid-19: What we’ve learned during the pandemic so far

It's now been two years since Chinese authorities first informed the World Health Organization about an unknown virus in Wuhan. How has our understanding of the virus changed since then and where does that leave us?

Two years of covid-19: What we’ve learned during the pandemic so far
It's now been two years since Chinese authorities first informed the World Health Organization about an unknown virus in Wuhan. How has our understanding of the virus changed since then and where does that leave us?