Evaluation Of Polio Vaccine Safety And Epidemiological Protection Effect In Jiangxi Before And After Immunization Strategy Adjustment

Objective:Systematically evaluate the safety and epidemiological protection effect of different polio vaccines used in Jiangxi before and after the adjustment of immunization strategy(May 1,2016),so as to provide a reliable and scientific basis for the formulation of polio prevention and control measures and the adjustment of immunization strategy in China in the future.Methods:Collect the adverse events following immunization(AEFI)case data reported by trivalent oral poliomyelitis attenuated live vaccine(t OPV),bivalent oral poliomyelitis attenuated live vaccine(b OPV)and inactivated polio vaccine(IPV)before and after the adjustment of polio vaccine immunization strategy in Jiangxi,as well as the case information of reported acute flaccid paralysis(AFP)cases,and conduct comparative analysis by descriptive epidemiological method.Results:Safety evaluation of polio vaccine1.The AEFI reported incidences per 100 000 doses for t OPV,b OPV and IPV were 2.23,7.04 and 17.91,respectively.The incidences per 100 000 doses for t OPV,b OPV and IPV of common adverse reactions were 1.55,5.49 and 15.14,respectively.The incidence per of 100 000 doses for t OPV,b OPV and IPV of rare adverse reaction reports were 0.52,1.27 and 2.22,respectively.Among the rare adverse reaction of t OPV,b OPV and IPV,the incidence per 100 000 doses of allergic rash were 0.36,1.03and 1.95,respectively.The incidence per 100 000 doses of vaccine-associated paralytic poliomyelitis(VAPP)were 0.06,0.10 and 0.00,respectively.2.The reported cases of t OPV,b OPV,IPV AEFI were mainly 0-year-old children and commom adverse reactions,which mostly occurred within 2 days after vaccination,in Jiangxi.Allergic rash was the main case of rare adverse reaction.3.The incidence of IPV-salt and IPV-Sabin AEFI per 100 000 doses were 19.12and 17.03,respectively.The incidence of common vaccine reaction reports per 100000 doses were 16.41 and 14.22,respectively.The incidence of rare vaccine reactions per 100 000 doses were 2.07,2.34,respectively.Among the rare vaccine reactions,the incidence of allergic rash per 100 000 doses were 1.68,2.15,respectively.Effect evaluation of polio vaccine1.Before and after the polio vaccine immunization strategy adjustment,599cases and 526 cases of AFP cases were reported in Jiangxi respectively.The reported incidence rate was 2.02 and 1.88 per 100 000 respectively.Incidence rate of reported cases before and after adjustment of immunization strategy was not statistically significant.(χ~2=1.45,P=0.23).2.Before and after the adjustment of polio vaccine immunization strategy,no clinically consistent cases of poliomyelitis and confirmed cases of wild poliovirus(WPV)were found in Jiangxi.One case of vaccine derived poliovirus(VDPV)was found before the adjustment of polio vaccine immunization strategy,and no VDPV case was found after the adjustment.3.Before and after the adjustment of polio vaccine immunization strategy,the proportion of AFP cases Aged 0~4 years old was 60.50%and 52.09%respectively.There was significant difference in age composition before and after the adjustment of immunization strategy(Z=-4.47,P=0.00).The sex ratios were 1.80:1 and 1.91:1respectively.There was no significant difference in gender composition before and after immune strategy adjustment(χ~2=0.21,P=0.65).Sporadic cases were the main cases in all months and cities divided into districts,and scattered children accounted for 67.78%and 48.48%respectively in the occupational distribution.Compared with the occupational composition before and after the adjustment of immunization strategy,the proportion of scattered children decreased significantly after the adjustment(χ~2=44.05,P=0.00).There was no significant difference in the composition of disease spectrum before and after immune strategy adjustment(χ~2=19.34,P=0.15).The residual paralysis rates were 17.53%and 19.58%respectively.There was no significant difference in prognosis before and after immune strategy adjustment(χ~2=1.13,P=0.57).4.Before and after the adjustment of polio vaccine immunization strategy,the positive rates of poliovirus(PV)isolation in AFP cases in Jiangxi were 1.84%,0.58%respectively.Compared with the positive rates of PV before and after the adjustment of immunization strategy,the positive rate of PV after the adjustment decreased significantly(χ~2=3.66,P=0.04).The positive rates of non-polio enterovirus(NPEV)isolation were 2.02%,6.91%,respectively.There was no significant difference in the positive rate of NPEV before and after immune strategy adjustment(χ~2=3.66,P=0.04).