Influencing factors of residual paralysis in acute flaccid paralysis cases with isolation of poliovirus in Jiangsu province

Objective To analyze the epidemiological characteristics of acute flaccid paralysis(AFP) cases with isolation of poliovirus and to find out factors associated with residual paralysis.Methods During 2004-2009,1 548 AFP cases were reported.The stool specimens were collected and poliovirus was detected among 1 540 cases.The description epidemiological methods were used to analyze the characteristics of AFP cases with positive poliovirus detection.Results Sixty of 1 540 AFP cases had poliovirus positive stool specimen with a isolated rate of 3.90% of vaccine associated poliovirus.All cases were sporadic and the male was more than the female.The rate of poliovirus isolated and residual paralysis in the AFP cases aged 0-1 years was higher than those of aged 1-2 years and ≥3 years.The rates of residual paralysis were higher in the AFP cases aged 0-1 years,unvaccinated or not full course vaccinated(< 3 times),and the time between oral poliovirus vaccine(OPV) immunization and disease onset less than 60 days.All five AFP cases with 1 dose of OPV and with the isolation of mixed type poliovirus were residue paralysis.The general incidence of vaccine-associated paralytic poliomyelitis (VAPP) was 0.29/1 000 000,and the incidence of VAPP among the new borns after their first OPV immunization was 1.56/1 000 000.Conclusion There were some AFP cases with isolation of poliovirus and VAPP cases in Jiangsu province.Main influencing factors of residue paralysis are age,history of vaccination,and the time between OPV immunization and disease onset.