<prompt> Which of the following is not a type of Vaccine derived polio virus?cVDPViVDPVmVDPVaVDPV  <response>: Vaccine derived polio virus VDPVProperties of VDPV: Occurs due to Sabin OPV vaccine: P3 60 of all cases P2 P1 Clinical presentation indistinguishable from Wild polio virus WPV cVDPV present similar public health threat like WPV iVDPV prolonged infection may transmit virus to othersIncidence of VDPV: 4 cases per million birth cohort per yearTypes of VDPV: cVDPV: Person-to-person transmission in community iVDPV: Isolates from immunodeficient persons aVDPV: Ambiguous from healthy person or sewage isolatesKey risk factors for cVDPV emergence: Development of immunity gaps due to low OPV coverage Prior elimination of WPV types Low routine immunization coverage with trivalent OPV Insensitive AFP surveillanceDiagnosis: Real time Reverse transcription PCR nucleic acid amplification 