Evaluation Of Effectiveness Of Hand, Foot And Mouth Disease Intervention Measures Based On System Dynamics Model

Background and objective Hand,foot and mouth disease(HFMD)is a common acute infectious disease caused by various enteroviruses.Although hand,foot and mouth disease vaccines have been marketed and health and medical conditions have been improved,the number of adults as recessive carriers is huge,and preschool children lack protective immunity against enteroviruses,making preschool children the main target population.In addition,the incidence of HFMD has obvious seasonality and periodicity,which promote the persistence of HFMD epidemic.This study intends to understand the burden of hand-foot-mouth disease in Jiangsu Province through literature search,field investigation and expert interviews,then construct a human-to-human transmission system dynamics model to evaluate the prevention and control effect of different interventions and explore the impact and role of hand-washing measures in the prevention and control of hand-foot-mouth disease epidemic.Methods(1)In this study,the confirmed cases of HFMD reported in Nanjing and Suzhou of Jiangsu Province from January 2017 to May 2018 were taken as research objects.The direct economic burden was collected by case investigation and hospital management system.The quality of life of the children was investigated by the TAPQOL scale,and the disability adjusted life years(DALY)were calculated to assess the health loss of the patients.(2)Based on the comprehensive inclusion of hand-washing research literature on hand-foot-mouth disease since 2009,the study used evidence-based medicine to analyze the relationship between hand-washing and HFMD incidence.The statistical analysis results might provide epidemiological evidence for the later construction of the dynamic model.Excel was used to extract data and STATA software was used to analyze data.The merging effect(OR)and 95% confidence interval of each factor were estimated.(3)According to the relevant links of HFMD transmission,natural history of HFMD,epidemiological investigation and medical experts' experience,construct human-human transmission dynamics model was constructed.The parameter values of the model were estimated based on literature review,expert consultation,and field survey.The VENSIM software was used to simulate the spread of the epidemic situation with and without intervention,and then evaluate the effects of different interventions.Results(1)362 cases were collected with the mean value of age(36.77±21.51 months),and male female ratio(1.99:1).There direct economic burden was ?18546.81,accounting for 38.55% of Nanjing's per capita disposable income(?48104),and 33.57% of Suzhou's per capita disposable income(?50603).There was no gender difference in direct economic burden.The direct economic burden of patients of different age groups were similar.But Nanjing's direct economic burden was higher than that of Suzhou(p<0.05).Multivariate analysis showed that the direct economic burden of hospitalized patients with HFMD was affected by variables such as region and length of hospital stay.There were no deaths in 362 patients with severe hand,foot and mouth disease.The total DALY was calculated to be 0.79 person-years,and the per capita loss was 2.19 person-years/thousand people.(2)This study systematically evaluated the effect of hand-washing on HFMD.The results showed that the standard hand washing(OR=0.30,95%CI: 0.21,0.43),good hygiene(OR=0.56,95%CI: 0.48,0.66),washing hands after playing with other children(OR=0.32,95%CI: 0.20,0.51),hand washing before and after meals(OR=0.29,95%CI: 0.23,0.38),wash hands before meals(OR=0.32,95%CI: 0.22,0.46),wash hands after defecation(OR=0.49,95%CI: 0.40,0.59),wash hands with soap(OR=0.55,95%CI: 0.36,0.84),the parents wash their hands before taking care of the children(OR=0.35,95%CI: 0.24,0.50),the parents wash their hands before feeding the children(OR=0.12,95%CI: 0.05,0.30),the frequency of parental washing(OR=0.23,95%CI: 0.10,0.54)and the 10 research factors are associated with the presence of HFMD which all are protective factors..(3)The human-human dynamic model(susceptible-vaccinated-hand-washingexposed-infections-quarantined-removed,SVHEIIeQR)were constructed.Compared with the actual data,the SEAIRC model had a goodness of fit of 0.850.The effect evaluation of different interventions(vaccination,hand washing and isolation treatment)showed that vaccination and hand washing were effective measures to control the epidemic of HFMD.Sensitivity analysis showed that the proportion of dominant infections,vaccination rate,hand washing rate,infectious coefficient of dominant infections to susceptible persons and infectious coefficient of recessive infections to susceptible persons were sensitive to the whole model.With the increase of dominant infection rate,children's vaccination rate and children's good hand washing rate have greater impact on the prevalence of hand,foot and mouth disease.Reducing the contact infection of recessive infections to susceptible people would make the control effect of HFMD more obvious.For dominant infections,isolation treatment should be actively carried out.The combined effects of the three measures had a significant effect on reducing the incidence of hand,foot and mouth disease.Conclusions The disease burden of HFMD and the quality of life of children are more serious,mainly affected by region and age.The preliminary results indicated that vaccination and hand washing would control the tranismission of HFMD.