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What is Which of the following is not a type of Vaccine derived polio virus? and explain in detail?
Vaccine derived polio virus (VDPV)

Properties 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 others

Incidence of VDPV: 4 cases per million birth cohort per year
Types of VDPV:

– cVDPV: Person-to-person transmission in community
– iVDPV: Isolates from immunodeficient persons
– aVDPV: Ambiguous from healthy person or sewage isolates

Key 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 surveillance

Diagnosis:

– Real time Reverse transcription
– PCR nucleic acid amplification