If God exists, then why can he not prevent us from coronavirus?

God can certainly prevent the corona virus, but why would He? Look how beneficial this virus is to nature and her inhabitants. Nature is practically blooming, as soon as human activity is reduced on her surface. Pollution of her air and water is way down, animals are coming out to walk the streets of the cities.

Ask all the cows, pigs, sheep, and chicken that are being slaughtered by the millions every day the world over, if they would like God to take away the coronavirus. The virus is a saving grace to these animals. It has stopped, for a while at least, the daily mass-murder on them.

The fact is, that the present human consumer civilization is like a disease on nature. The way I see it, the coronavirus is God’s cure of the disease on nature, called humanity

Krishna says:

Those who are demoniac do not know what is to be done and what is not to be done. Neither cleanliness nor proper behavior nor truth is found in them. (Bg 16.7)

They say that this world is unreal, with no foundation, no God in control. They say it is produced of sex desire and has no cause other than lust. (Bg. 16.8)

Following such conclusions, the demoniac, who are lost to themselves and who have no intelligence, engage in unbeneficial, horrible works meant to destroy the world. (Bg. 16.9)

Taking shelter of insatiable lust and absorbed in the conceit of pride and false prestige, the demoniac, thus illusioned, are always sworn to unclean work, attracted by the impermanent. (Bg. 16.10)

They believe that to gratify the senses is the prime necessity of human civilization. Thus until the end of life their anxiety is immeasurable. Bound by a network of hundreds of thousands of desires and absorbed in lust and anger, they secure money by illegal means for sense gratification. (Bg. 16.11-12)