In this case the virus is a result of one of the polio vaccines.

Whomever brought it would very possibly have done the right thing and gotten vaccinated recently, but the live attenuated polio vaccine very occasionally leads to shed attenuated polio virus reverting to full strength.

And that's definitely the reason they didn't get vaccinated, which probably wasn't fundamentally egocentric at all /s

Huh? They did get vaccinated.

EDIT: It is possible the import could have come from an unvaccinated person too, having gotten it from someone who has been vaccinated. But that the virus is vaccine-derived means the ultimate source is someone who got the vaccine.

I realize this might be a shock… But vaccines fail all the time. Their immunity wanes, they cause adverse events and sometimes they spawn rogue strains like what happened with Polio.

BTW we have a case study unfolding real time on restricting people’s travel based on vaccination status. As the COVID-19 vaccine does not prevent transmission, infection or spread, it was a complete disaster. Meanwhile unvaccinated people with natural immunity who don’t spread were unfairly punished for noncompliance.

They were vaccinated... If you read the article, the headline is "Vaccine-derived poliovirus... detected" When you take the oral polio vaccine, its a live virus and sometimes that virus can be spread. So in this case, someone who had likely recently been vaccinated via the oral vaccine used a toilet in London and the virus was detected in the sewers.