| [Background]The occurrence and prevalence of infectious diseases can be prevented through vaccination,which is generally agreed and accepted by the public all over the world at present.Vaccination is the most specific,effective and economical measure to prevent,control and eliminate infectious diseases,so that vaccines are considered the greatest public health achievement of the 20th century.However,because vaccines are exogenous biological agents for human body like drugs,very low probability of adverse reactions after inoculation will inevitably occur in some individuals.But the tolerance for adverse reactions,especially severe ones after vaccination,is much lower than treatment after illness,for that the persons are healthy or in a subclinical state before vaccination,which putting a brake on development of immunization and facilitating the development of AEFI surveillance to some extent.According to the recommendations of WHO,many countries in the world had established and carried out successive and effective AEFI surveillance systems since the 1990s.With the gradual development and expansion of China’s vaccination work,especially since the implementation of the national immunization program,the number of vaccine types and doses gradually increased,as well as the greatly improved vaccination rate,the number of AEFI cases after vaccination also increased,which gradually attracted the attention of the public.In order to fully understand and master the actual situation of AEFI after vaccination and provide data for the safety evaluation of the vaccine on the market,China established the AEFI surveillance system in 2005 and popularized nationwide use in 2008.In order to better regulate and guide the national AEFI surveillance,the general office of the ministry of health and the office of the national FDA jointly formulated and issued the national AEFI surveillance program in 2010.Recently,China’s AEFI surveillance system has been improved day by day,monitoring and analysis of relevant data are of great practical significance for the timely detection of AEFI cases,improvement of the vaccination services quality,vaccine safety evaluation and enhancement of public confidence in preventive vaccination.[Objectives]1.To evaluate the operation of AEFI surveillance system through the completion of AEFI monitoring indicators in Tai’an City from 2012 to 2016.2.To understand comprehensively the classification and epidemiological characteristics of AEFI cases,and to evaluate the safety of vaccines and the quality of preventive vaccination services through the descriptive analysis of AEFI monitoring data in Tai’an City from 2012 to 2016.3.Using time series model to predict the occurrence of AEFI in Tai’an City in 2017.4.To provide guidance for improving the service quality of vaccination,preventing and controlling possible adverse reactions after vaccination,establishing a standardized safety surveillance system for vaccination,and to provide the basis for the formulation of relevant public health strategies and measures.[Methods And Contents]All the AEFI cases and relevant indicators reported in the "statistical analysis" function as well as the number of inoculation agents of all vaccines in the routine vaccination report(category Ⅰ and Ⅱ)were collected in Tai’an City from 2012 to 2016,through the AEFI monitoring module and vaccination module from China immunization information system.The number of vaccine doses was collected through the annual report of supplementary(enhanced)immunization/leak seeding activities.Generate the collected data into Excel 2016 basic data files in different years;and then,sort,merge,classify and calculate the required data to generate different worksheets.Finally,the calculated data were imported into SPSS 23.0 statistical software for analysis.1.Descriptive epidemiological methods were used to analyze the completion of AEFI monitoring indicators,such as the number of reported cases,48-hour report rate,48-hour investigation rate.2.The characteristics of classification of AEFI cases,age and sex distribution,time distribution,types of vaccine,regional distribution,abnormal reaction clinical diagnosis,major clinical symptoms,the time interval distribution from the vaccine to react and so on were analyzed through descriptive epidemiological methods.Significance tests were conducted for the reported incidence of AEFI at different times,in different regions,between NIP(National Immunization Program,NIP)and non-NIP vaccines with SPSS 23.0 statistical analysis software.3.A prediction model was established through time series analysis in SPSS 23.0 statistical analysis software,and parameter comparison was conducted between the optimal prediction model selected and the manual prediction model.Comparison and validation between the AEFI cases by month in 2017 predicted with the optimal prediction model and actual number.The 95%confidence interval and MAPE(Mean Absolute Percentage Error,MAPE)were used to evaluate the accuracy of the prediction model.[Results]1.The evaluation of AEFI surveillance systemCases of AEFI were reported in Tai’an City every year from 2012 to 2016,with 4325 cases reported totally.The number of AEFI cases reported increased linearly since 2012 to 2014,and began to decline slowly since 2014,with the lowest number in 2012(666 cases)and the highest number in 2014(983 cases).The total 48-hour reporting rate was 99.50%,with the highest 100%in 2014 and the lowest 99.10%in 2012.The total 48-hour survey rate was 93.52%,with the highest 100%in 2014 and 2015 and the lowest 86.67%in 2013.2.The classification of AEFIAmong the 4,325 AEFI cases,the proportion of general reactions was the highest(98.47%),followed by abnormal reactions(1.09%)and the lowest coincidence ones(0.44%).There were no vaccine quality accidents,vaccination accidents and psychogenic reactions.The composition of AEFI cases in different years from 2012 to 2016 was consistent with the total.3.The epidemiological characteristics of AEFI3.1 Three-dimension distribution in epidemiologyAmong the 4,325 AEFI cases,age<1 years old accounted for the largest proportion,and age>7 years old accounted for the smallest proportion,which was roughly the same as the age distribution in each year.Males had more cases than females,with a sex ratio of 1.33:1.AEFI cases had been reported every month of the year from 2012 to 2016.The number of reported cases presented seasonal variation each year,which began to increase in spring,up to its peak in summer,then began to decline in autumn but slightly increased in winter.The incidence difference of annual report had a statistical significance(χ2=139.726,P<0.001),with the lowest incidence in 2013 and the highest in 2016.AEFI cases had been reported in each county every year.However,the incidence difference of AEFI cases showed a statistical significance among different areas(χ2=132.529,P<0.001),with the highest incidence in Tai’shan County and the lowest in Xin’tai City.3.2 Analysis on the incidence of AEFI in different vaccines34 vaccines and 11215437 doses had totally been used for vaccination in Tai’an City since 2012 to 2016,with a reported AEFI incidence of 38.56 per 100,000 doses.The reported incidence of 12 NIP vaccines was 36.67/100,000 doses,while 22 non-NIP vaccines was 44.52/100,000 doses,which was higher than the former(X2=32.834,P<0.001).The highest reported incidence of vaccine was acellular DPT vaccine among NIP vaccines,with a rate of 108.79 per 100,000 doses.While inactivated JE vaccine among non-NIP vaccines,with a rate of 286.38 per 100,000 doses.The incidence of 47 abnormal reactions was 0.68 per 100,000 doses.BCG lymphadenitis was the most 17 cases,and the highest incidence of 5.52 per 100,000 doses in 10 clinical diagnoses.3.3 Main clinical symptoms of AEFI and inoculation-reaction time intervalThe main clinical symptoms of AEFI were fever,local redness and local induration.Fever accounted for the highest proportion(76.32%),with the body temperature of 81.55%fever cases>38.6℃,which was followed by local redness and local induration.The 87.68%of AEFI cases occurred in<1 day after vaccination,which was the highest proportion,while 0.72%after>15 days with the lowest.4.The prediction and model evaluation of AEFIThe simple seasonal/exponential smoothing prediction model selected by the expert modelers in SPSS 23.0 was the best of the five models in terms of stationary R2,MAPE,and standardized BIC value.The comprehensive evaluation shows that the prediction model selected by the expert modeler was better than the traditional manual model in predicting effect.The simple seasonal/exponential smoothing model was used to predict the number of AEFI cases per month in 2017,and it was found that the actual number of cases fell into the 95%confidence interval of the corresponding predicted value,and MAPE was small,indicating that the prediction accuracy of this model was relatively high.[Conclusions]1.The AEFI surveillance system-of Tai’an City works well,and the sensitivity of surveillance remain stable on the basis of improvement,but the surveillance timeliness needs to be further strengthened.2.Continuous dynamic surveillance defined classification,population,time,region,vaccine type,main clinical characteristics and inoculation-reaction time interval of AEFI,which should be the focus of surveillance.3.The simple seasonal/exponential smoothing model can be used as a good prediction model to predict the number of AEFI cases,which is especially suitable for the promotion and use in the grass-roots CDC workers.[Suggestion]AEFI can’t be eliminated in practice,but it will be effectively reduced and the injury caused by vaccination will be minimized by taking the following measures.1.Strengthen job responsibility and data analysis capabilities to improve their professional quality and management skills.2.Regularly carry out monitoring index evaluation to improve the surveillance quality.3.Correctly grasp the vaccination taboo,regulate the behavior of vaccination,the vaccine cold chain operation,strictly under observation system,reduce the occurrence of AEFI.4.Carry out health education on vaccination and related common sense,so that children’s parents can get correct understanding of AEFI. |
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