system
Given the following post, respond as if you're commenting on Reddit:
human
Why did we stop inoculating against smallpox?

I understand the amazing human achievement that the disease was eradicated. That said, we have an effective method against keeping people from getting sick from any possible accidental or other recurrence of the disease, so why don’t we continue using it widely just in case? I’ve also seen that it is/was effective in suppressing other “pox” diseases (eg, monkeypox), which seems like a big benefit.

So why did we just…stop? Were there major costs and/or side effects that made it not worth it? Or is it kinda just a big victory lap that we might regret?
gpt
Basically, every medical procedure has risk of something going wrong, and some benefit. If the benefit doesn’t outweigh risks, it’s not recommended. 

For smallpox, it’s eradicated; it doesn’t exist in the population. So inoculating against it gives no benefit. So even though vaccines are low-risk, there is some risk. Infections, adverse reactions, and mishaps with needles can happen, even if they are excessively rare. So despite the low risk, no benefit means the smallpox vaccination isn’t necessary.