The fight for polio eradication has been making a lot of progress recently, highlighted by Africa celebrating one year without any new cases of wild polio earlier this summer. However, there is unfortunate news from the Ukraine: 2 new cases have popped up in a country which had not had a case of the disease since 1996.
These two cases are actually oral vaccine-derived. This occurs because children who get the oral vaccine shed the attenuated virus in their feces, which occasionally can mutate and infect unvaccinated children. These outbreaks of vaccine-derived polio are generally less destructive, but healthcare workers are still concerned because Ukraine is susceptible due to only about 50 percent of children there being vaccinated against the virus.
Actual wild cases of polio are still being reported in just two countries: Afghanistan and Pakistan, while Madagascar and Nigeria have both experience outbreaks of vaccine derived polio.
The last case of polio in Europe was in 2010 when the virus was imported from Tajikistan to Russia. In that outbreak 14 people were affected.