I don’t understand how the current strategy can be expected to work. There are two vaccines: IPV and OPV. IPV does not cause outbreaks, but it does not induce s

I don’t understand how the current strategy can be expected to work. There are two vaccines: IPV and OPV. IPV does not cause outbreaks, but it does not induce sterilizing immunity [0]. So polio (harmless vaccine polio or dangerous polio, vaccine-derived or otherwise) can circulate in IPV-vaccinated populations. But the US hasn’t administered OPV since 2000 [1]. So polio can circulate in the US without causing symptoms! Anywhere with a sufficient population of people under 23 can be a reservoir of polio. I don’t understand how the overall strategy can be expected to eradicate polio. Even if the nOPV vaccine were perfect, any reintroduction of polio from any source (wild, old type 2 vaccine-derived, nOPV-derived) could circulate in the US and then be reintroduced elsewhere from here. I don’t get it. Presumably the US should start administering nOPV just to control its own outbreak. [0] https://pubmed.ncbi.nlm.nih.gov/22532797/ https://pubmed.ncbi.nlm.nih.gov/22532797/ [1] https://www.cdc.gov/vaccines/vpd/polio/index.html https://www.cdc.gov/vaccines/vpd/polio/index.html