A 5-year-old child from a rural area is brought with progressive, asymmetric flaccid paralysis affecting the right leg, which began 5 days after a febrile illness. The child received 2 doses of OPV. CSF shows mild lymphocytic pleocytosis. Which of the following types of vaccine-associated paralytic poliomyelitis (VAPP) is most likely if this child's paralysis is caused by the polio vaccine?
- A Poliovirus type 1-associated VAPP in a vaccine recipient
- B Poliovirus type 2-associated VAPP in a vaccine recipient
- C Poliovirus type 3-associated VAPP in a vaccine recipient
- D Vaccine-derived poliovirus (VDPV) type 2 (cVDPV2) causing circulating VDPV ✓
Explanation
Since the switch from trivalent OPV (tOPV) to bivalent OPV (bOPV, types 1 and 3) in April 2016, and subsequent introduction of IPV for type 2 immunity, the dominant cause of VAPP and outbreaks in incompletely vaccinated populations is circulating vaccine-derived poliovirus type 2 (cVDPV2), which arises from reversion/divergence of type 2 Sabin strain after prolonged circulation. Type 2 wild poliovirus was declared eradicated in 2015, but cVDPV2 has continued to cause outbreaks. A child who received only 2 OPV doses (now bOPV, lacking type 2) has no type 2 immunity and is at risk from cVDPV2.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.