// Dying with Covid mentioned on the death cert. is different to dying OF Covid. //
Indeed, but this is why the focus has shifted in recent weeks to all-cause excess mortality, which sidesteps that ambiguity. If, in normal circumstances, you can expect c. 10,000 deaths a week, and if, after a novel virus for which there is no natural immunity emerges, you see that jump up to 20,000+ deaths, then it is not unreasonable to draw a link between the two.
There will remain a great deal to understand about this, and it is indeed sadly certain that we'll never fully know the true death toll of Covid-19, either because of the with/of debate or because in some countries the statistics aren't even made honestly available for one reason or another. What we *do* know is that this new virus can and does kill, and clearly has done so in significant numbers.