In 2012, 58 cases causeb by Circulating vaccine-derived poliovirus.
Nigeria 4 reported cases.
Pakistan 15 reported cases.
Afghanistan 4 reported cases.
Somalia 1 reported cases.
Chad 12 reported case.
Kenya 3 reported cases.
DR Congo 17 reported cases.
Yemen 2 reported cases.
Vaccine-derived polioviruses (VDPVs) are rare strains of poliovirus that
have genetically mutated from the strain contained in the oral polio
vaccine.
Read more www.polioeradication.org
