Clearly there is a virus.
The most likely reason that governments will not hand over proof of virus isolation is because it will reveal that this virus was indeed a natural virus that was tweaked in a lab with the intent of spreading rapidly through a population, and that they have been lying to the population about its origins.
Such a virus is only created for nefarious purposes. It was likely released in order to create havoc and gain more control for international institutions and profits for the corporations that are entwined in the corporate colonialism scheme that has come to be. The mainstream media are part of the corporate colonialism crew.