[pedalpete]

Doesn't that assume that it had already jumped to monkeys from humans, or from bat to monkey to human?

I have no idea how the process works, and if it easier for a disease to jump from primate to human or vice-versa than it is from other species.

[Tagbert]

The original comment was that there is no risk of Covid in Macaques jumping to humans since Covid is already in the human population.

In general it is probably easier for a virus to jump between closely related species that it is to jump between more divergent species. Humans and macaques only split about 20-30 million years ago. Humans and bat probably split 70 million years ago. It doesn’t mean that bat viruses can’t make the jump, many do, just that it might be harder for them to establish themselves in humans. Bats live in very tight quarters and end up exchanging a lot of virus between each other. This is a great breeding ground for viruses so there are probably more virus types in bats than in many other animals. That gives a large pool of viruses which have the potential to infect humans.