Did not know where else to publish this:
The U.S. Centers for Disease Control and Prevention (https://wwwnc.cdc.gov/travel/notices/level2/global-polio) is warning travelers about polio in 32 countries, including several in Europe (https://www.cruisecritic.com/destinations/europe).
Travelers are advised to "practice enhanced precautions” before visiting any of these countries, and to ensure they are up to date on polio vaccinations before going abroad.
The agency also recommended a lifetime booster dose of the polio vaccine for adults who already completed the routine polio vaccine series.
CDC’s list of destinations with circulating poliovirus includes European countries such as Germany, Finland, Poland, and the U.K.