system
Given the following post, respond as if you're commenting on Reddit:
human
Are there viruses that are benign but highly infectious that we don’t know about until after it’s spread?
gpt
Polyomaviruses are very common. HPyVs 9 and 12 are not known to cause any disease. BK and JC viruses infect the large majority of humans. There are 13 we know of that infect humans, there are probably more we just haven't found yet, and in general they only cause disease for immunocompromised patients, if any disease is even known.