It's not necessary to trust the numbers. If they had large outbreaks, we would know. We are talking about a country of 1.4 billion people which has plenty of contact with the outside world, it's not North Korea. They could cook the numbers but it would just be impossible to hide widespread community spread.
And we can be darn sure the CIA would be screaming from the rooftops of all its propaganda outlets the perceived failings or weaknesses in China's COVID response. The silence there is all you need to hear to know what's up.
