> At the beginning there were some authorities (China, WHO) claiming there was no human-to-human transmission.

I don't understand how this misconception persists. That is not what the WHO statement said.

The statement was that the outbreak was not being sustained by community transmission, and that they believed (this was very early on) that the cases from the Wuhan market were all due to exposure to a single case or pathogen.

This was, obviously, wrong. But at the time it wasn't unreasonable to believe. That's the way most outbreaks work when you catch them early.

At no point did anyone say that a respiratory coronavirus was not contagious, which is how people insist on treating that statement. Of course these things are contagious, that's how they spread.