Two children have been stricken and paralyzed by polio in southwestern Ukraine, according to the World Health Organization. These are the country's first cases of the paralytic disease in 9 years. It is the first outbreak of the disease in Europe since 2010 and is a major setback in the campaign for global eradication of polio.
Ukraine has been at high risk for a polio outbreak for some times because its vaccination rates; are low. Only half of children were immunized against diseases like polio last year.
The two cases resulted from a mutated polio virus in the oral polio vaccine. In rare instances, the virus in the vaccine can evolve into a strain that causes new outbreaks. Oral polio vaccine contains a very weak live virus and is considered very safe and effective in preventing the disease. But children who have received the oral vaccine can excrete it, and the virus can mutate in the environment within about 12 months and begin causing infection and paralysis in unvaccinated children.
Vaccine-derived polio strains tend to spread less easily than wild strains of polio. They also tend not cause as many cases as the wild virus. Ukraine has been free of wild polio virus since 1996
The children in Ukraine are a 10-month-old and a 4-year-old. But there may be others who are carrying, and possibly spreading, the virus without showing symptoms.
There is fear that polio could spread further the Ukraine, but the threat of the disease spreading to nearby Romania, Poland, Hungary and Slovakia is low, according to WHO.
There is no cure for polio, which attacks the nervous system and can cause irreversible paralysis within hours of infection. It mainly affects young children in areas with poor sanitation. A global vaccination campaign has largely stamped out the virus, and only Pakistan and Afghanistan have reported cases of wild polio virus this year. Madagascar and Nigeria have suffered vaccine-related outbreaks, like Ukraine.
Turkey, the last country in Europe where polio was endemic, has been rid of the disease since 1999. Europe's last outbreak was in 2010, after the virus was imported from Tajikistan to Russia, leading to 14 cases.
