[plqbfbv]

> Is it working if it's not actually doing anything?

Yes, because unvaccinated humans lack immunity. A single imported case could spread rapidly through an unvaccinated population.

I found this informative ECDC page: https://www.ecdc.europa.eu/en/poliomyelitis/facts

Quotes:

- Poliovirus can survive at room temperature for a few weeks in soil, sewage, and water

- It's highly infectious with sero-conversion rates of 90–100% among household contacts

- Factors like poor sanitation, high population density, and low vaccine coverage all fuel transmission

Yellow fever needs mosquitoes to spread and has animal reservoirs. Once you reduce/eliminate transmission in those reservoirs, the virus basically can't circulate even with low human vaccination coverage. For polio, humans are the only reservoir, and it spreads directly person-to-person. That's why you can't just rely on vaccinating travelers.

Plus, vaccine-derived polio (cVDPV) is actively circulating in Nigeria and Chad right now. In 2025 alone Nigeria reported 62 cVDPV2 cases. This happens when vaccination coverage drops low enough for the weakened vaccine virus itself to mutate and spread. So it's not just reintroduction risk, the virus is actively evolving in low-coverage areas.

If a huge cluster were to emerge, you'd need rapid mass vaccination campaigns to stop it. That's way riskier than maintaining routine childhood vaccination.

[giantg2]

"Yes, because unvaccinated humans lack immunity. A single imported case could spread rapidly through an unvaccinated..."

That's assuming there would be an imported case. Travel restrictions can solve that. That's how we handle other US eradicated diseases, such as yellow fever.

You'd still need mass vaccination campaigns because immunity wanes over decades. If it resurges, it will rip through the elderly, especially nursing homes.

[beej71]

"such as yellow fever"

Yellow fever is spread through mosquito bites and polio is spread person-to-person. An imported case of yellow fever is nearly impossible to spread, while an imported case of polio is virtually certain to spread.

Sorry, but it's simply naive to think that in today's global world we would not import polio. It's already happening right now in the US. The only thing stopping the spread is our current high vaccination rate. You'd have to cut travel to zero in both directions to stop it.