Equilibrium Analysis And Intervention Mechanisms In Vaccine Markets From The Perspective Of Participants Behaviors

COVID-19,plaguing all around the world in 2020,has a significant threat to our public security.To mitigate this threat and achieve sustainable development in human health,getting vaccinated and enhancing its coverage are becoming a measure to prevent the spread of infectious diseases.Historical experience,however,indicates that there was a dilemma in vaccine markets,that is,both vaccine shortages in supply side and vaccine hesitancy in demand side caused the insufficiency of vaccine coverage and the resulting recurrence of infectious diseases.In light of this,how to solve this dilemma and to enhance vaccination coverage are hot and difficult points.Some pioneering papers have investigated the homogeneity of rational individuals,whereas this homogeneity does not consider the prevalent cases in which individuals are heterogeneous and their behaviors are bounded rationality.This gap leads to the inefficiency in catching the trends of infectious diseases,in conducting equilibrium analysis in vaccine markets,in designing government interventions.What is worse,public security will be challenged in a short run and the development of sustainable health may be damaged in a long run.Our paper considers the heterogeneity of both informational issues(i.e.,the uncertainties of vaccine yield and vaccine efficacy)and behavioral issues(i.e.,reference-dependent preference and social learning).First of all,in both demand and supply sides,a static game model is constructed for the quantitative analysis of vaccine shortage.Subsequently,focused on demand side,two dynamic game modes are built for the quantitative analysis of vaccine hesitancy.These three models analyze the underlying reasons and evolution paths for “how vaccine shortage and hesitancy affect its coverage” from the perspectives of decision rules and interaction effects.This analysis is incorporated into the equilibrium analysis and public administration,in order to recommend policy advices about optimizing government intervention and enhancing vaccine coverage.Three game models and relevant analysis are listed as follows.First,in both supply and demand sides,we consider yield uncertainty as well as the resulting reference dependence,and then construct a three-stage game model including individuals,a manufacturer and a government.This model majorly analyzes the interactions between reference dependence,equilibrium analysis and intervention mechanisms.Some results are derived.Reference dependent preference not only causes supply shortages,but also has different significant implications in intervention mechanisms.The positive implications are that,during the process of maximizing social welfare,this preference(1)makes one-sided(demand)behavioral mechanisms reduce government intervention and(2)endows special two-sided behavioral mechanisms to achieve budget-neutrality.The negative implications are that,the presence of reference dependence(1)makes one-sided(supply)behavioral intervention mechanisms so inefficient that social welfare fails to maximize as well as(2)forces general two-sided behavioral mechanisms complex in intervention structure and extent.Second,focused on demand side,we consider two informational issues associated vaccine efficacy: multi-information(i.e.,contradiction information and others' decision information)and single-information(i.e.,others' reviews).Then,these two informational issues and the resulting participant behaviors are introduced into their decisions,dynamic game models from different perspectives characterize vaccine hesitancy.On one hand,based on multi-information and the perspective of reference points,we establish a two-stage game model to analyze the relationship between contradiction information and reference point formation,as well as the relationship between others' decision information and reference point updating.Further,how the two relationships affect individuals' decisions and public sentiment is revealed.Some results are obtained.Multi-information issues in the first stage form reference points and its resulting contradiction information.This forces some individuals to delay their decisions(i.e.,vaccination hesitancy),instead of immediate vaccination.After more information disclosed in the second period,these delayed individuals update reference points and exhibit psychological utility that is a major factor determining whether to get vaccinated.Based the above analysis,the government should exert costly effort to filer contradictory information about vaccines.This intervention strategy has a result of “killing two birds with one stone”:(1)it reduces the number of delayed individuals and boosts the equivalent number of vaccinated individuals,directly by reference points formation;(2)it increases the psychological utility of hesitant individuals choosing to get vaccinated,indirectly by reference points updating.On the other hand,focusing on single-information and social learning,we build a two-period dynamic game model among individuals,a manufacturer and a government.Then,this model is incorporated into the framework of equilibrium analysis and public management.This framework analyzes how the interactions between social learning from efficacy reviews and economic incentive from dynamic subsidy affect vaccination coverage.Some conclusions are yielded.(1)Social learning induces the perceived gap in two-period vaccine efficacy,which is considered as information incentive to generate strategic behaviors(including vaccine hesitancy).(2)To mitigate the above behaviors,dynamic subsidies from the government have different implications in enhancing vaccination coverage.Subsidizing to the manufacturer(i.e.,cost subsidy)is always inefficient due to the lack of economic incentive in early vaccination,while subsidizing to individuals(i.e.,sales subsidy)can form economic incentives to increase vaccine coverage by the adjustments from subsidy time(pre-announced or responsive)and limited budget.(3)Cost subsidy,an intervention mechanism from supply side,and sales subsidy,an intervention mechanism from demand side,have the following characteristics: cost subsidy and second-period sales subsidy alone are equivalent in the optimal subsidy level and the maximized social welfare,and both are inferior to the first-second sales subsidy alone in enhancing vaccine coverage.