We can, but if we’re not careful, it can come back.

After eradicating polio for decades, we saw a case for the first time in 2022. https://pmc.ncbi.nlm.nih.gov/articles/PMC9577438/

And given the drop in rates of immunization post covid, we can very expect more if the trend continues.

Well, it's complicated. As I understand, one of the polio vaccines - the oral one - has an unusual quirk.

The live virus used in it can reproduce and spread in low-vaccination communities. While the vaccine version of it will not cause paralysis, it can and occasionally does mutate back into a pathogenic variant.

So we're sort of maintaining a reservoir of polio, really.

Well, "can" is debatable. The only one we've effectively eradicated is smallpox and that was almost 50 years ago. Of course we couldn't actually eradicate it, though, and kept samples for "research purposes".