Polio Returns to Ukraine

Even before war with Russia, polio was creeping back into Ukraine. Last fall it paralyzed a 17-month-old girl in the northwest. Next it struck a two-year-old boy in the far southwest. Contacts tested positive. Because poliovirus is highly contagious and usually asymptomatic, one case signals a crisis. Polio cannot be cured, only prevented.

The culprit was not naturally occurring poliovirus, which circulates only in Pakistan and Afghanistan, but a mutation of a vaccine component that had passed from person to person. Counter-intuitive as it seems, the way to stop vaccine-derived polio is more vaccine. Mutation to a dangerous form takes months. In a well-vaccinated population, the weakened virus in oral polio vaccine dies out for lack of susceptible people to host it. Immunization rates in Ukraine were unfortunately low.

Health authorities in Ukraine, already struggling with a Covid surge, launched a polio vaccination response in February. War with Russia put the drive on hold. Medical supplies are running out. Bombs and battles shift health workers’ priorities. Massive population movements impede services. Refugees may carry virus unwittingly into neighboring polio-free countries.

Do not be surprised if we see more children in eastern Europe paralyzed before this is over. Basic health care is among the many casualties of war.

Image: Poster from Ukraine’s previous polio outbreak in 2015.