In Ukraine, 2
cases of circulating vaccine-derived poliovirus (oral polio vaccine)
type 1 (cVDPV1) have been confirmed, with dates of onset of paralysis on
30 June and 7 July 2015.
Both are from the Zakarpatskaya oblast,
in south-western Ukraine, bordering Romania, Hungary, Slovakia and
Poland. One child was 4 years old and the other 10 months old at the
time of onset of paralysis.
Vaccine-derived polioviruses (VDPVs) are strains of poliovirus that have
genetically mutated from the strain contained in the oral polio vaccine
and tend to spread and cause polio as the wild poliovirus.
Ukraine had been at particular risk of emergence of a cVDPV, due to
inadequate vaccination coverage. In 2014, only 50% of children were
fully immunized against polio and other vaccine-preventable diseases.