[Analysis on vaccine-derived poliovirus found from acute flaccid paralysis cases and effectiveness for emergency response in Binzhou in 2007].

Objective: To analyze VDPV found from acute flaccid paralysis cases and effectiveness for emergency response in Binzhou, Shandong in 2007.

Methods: Outbreak investigation, rapid evaluation for oral poliomyelitis attenuate live vaccine (OPV) coverage rate, active searched for acute flaccid paralysis (AFP)cases, supervision for VDPV case, virology and serology surveillance, mopping-up of OPV were used for this emergency response to prevent the possible VDPV spread.

Results: The case was reported from the AFP surveillance system. The poliovirus type I was isolated from stool specimen, which was identified as VDPV by gene sequencing. This AFP case was diagnosed as Guillain-barre syndrome (GBS) with 11 doses of OPV and normal self-immunity function test. The investigation results showed that the OPV coverage rates and the neutralization antibody to poliovirus type 1-3 were at high level among the local children, no similar VDPV was isolated from stools of healthy children around the case. The quality of AFP surveillance system was good, and had not found additional similar case in Bizhou city. Additional VDPV was not found in continuous stool specimen from this case. The case was diagnosed as VDPV infected vector but not VDPV case by the national and provincial expert group.

Conclusion: This VDPV was found in the area with high coverage rate OPV, There was no evidence for the VDPV circulation. The emergency response for the VDPV was rapid and effective. The VDPV surveillance and research related should be strengthened.