Predicting The Risk Of Illegal Vaccines In China

Since the disclosure of the "Illegal vaccine operation series case in Jinan,Shandong", this issue has attracted a great deal of attention and has led to public concerns about the safety and efficacy of the vaccines involved in this case. The main purpose of this paper is to scientifically and scrupulously analyze the possible geographic distribution of illegal vaccines in China and to provide a foundation to guide future governmental policies and actions.A species distribution model was used because of the advantages of using presence/pseudo-absence or presence-only data and performs well with incomplete species distribution data. A series of environment variables were used to simulate habitat suitability distribution. MAXENT (Maximum Entropy Model) and GARP (Genetic Algorithm for Rule set Production) were used to predict the risks of illegal vaccines in China and to define the spatial distribution and significant factors of the area at risk from illegal vaccines. The simulation precision of the models was assessed by the method of Receiver Operating Characteristic (ROC) curve analysis. Jackknife tests were used to evaluate the relative importance of socioeconomic variables.It was found that: (1) Shandong, Hebei, Henan, Jiangsu and Anhui are the main high-risk areas impacted by the vaccines involved in the Jinan case. (2) Population density and industrial structure are the main environmental factors affecting which areas may be at risk from illegal vaccines. (3)Both MAXENT and GARP produced good predictions for potential distribution of illegal vaccines. However, GARP predicted larger and more continuous suitable areas around illegal vaccines’ locations and fragmented spatial predictions where the illegal vaccines has never been found or collected before. MAXENT predicted a distribution that is a logical proportion of the study area and removed most of unlikely isolated areas.