Epidemiological Analysis on Suspected Vaccine Associated Paralytic Poliomyelitis in Shandong Province

Objective To explore the situation of vaccine associated paralytic poliomy elitis(VAPP)in Shandong province.Methods Eighty one suspected VAPP cases reported by acute flaccid paralysis surveillance system were analyzed on the stage of polio-free from 1993 to 2000 in Shandong province.Results The suspected VAPP incidences were from 0.27 to 1.33(the mean was 0.79)per 1 million usage doses of oral poliovirus attenuated vaccine(OPV).The incidence for first dose,second dose and 3 doses of OPV immunizat ion was 7.34,2.58 and 0.61 per 1 million usage doses of OPV,respectively.All suspected VAPP cases occurred in 55 counties with no obvious clustering distribution.The incidence of suspected VAPP in males was more than that in females.The results of poliovirus(PV)isolation from stools of the suspected VAPP cases showed that PV2 was more than PV1 and PV 3 among vaccine-contacted cases,and PV2 was almost equal to PV3 among other cases.The mean incubation period of suspected VAPP onsed was 45 days.All cases were maintained with residual paralysis by follow-up investigation after 60 days.Conclusion The further study on VAPP should be enhanced and inactivated poliovirus vaccine(IPV)should also be considered to use on rout ine immunization activity instead of OPV to eliminate the VAPP onset in China.