全球疫苗集中采购的价格效应OA

Objective:To evaluate the impact of international pooled procurement mechanisms,which are primarily represented by the United Nations Children's Fund(UNICEF)and the Pan American Health Organization(PAHO),on the procurement prices of vaccines.Methods:Based on 14 497 vac-cine procurement transaction records collected from 188 different countries spanning the period from 2013 to 2024,this research employed a high-dimensional fixed effects model along with an event study metho-dology to accurately identify the price effects and dynamic temporal trends,while simultaneously conduc-ting a multidimensional heterogeneity analysis.Results:(1)The baseline model demonstrated that,when compared to the independent self-procurement conducted by individual nations,utilizing pooled procurement through the UNICEF significantly reduced the average vaccine prices by 27.6％(β=-0.323,P＜0.01).The PAHO mechanism similarly exhibited an initial price reduction potential of ap-proximately 30.9％(β=-0.370,P=0.052).(2)The event study method strictly validated the parallel trend assumption(joint significance test of pre-treatment coefficients:F=0.27,P=0.845).Dynamic tracking revealed that a price reduction of approximately 30.0％(β=-0.356,P＜0.01)was achieved exactly in the year of transitioning from self-procurement to pooled procurement,and this reduc-tion effect remained persistently stable in subsequent years.(3)Heterogeneity tests revealed a significant"pro-poor"effect of pooled procurement:the price reduction margin obtained by small-scale buyers(38.5％,β=-0.487,P＜0.01)was significantly higher than that of large-scale buyers(22.5％,β=-0.255,P＜0.01).The marginal price reduction coefficient for non-Global Alliance for Vaccines and Immunization(GAVI)eligible countries(β=-0.418,P＜0.01)was substantially larger than that for GAVI eligible countries(β=-0.118,P＜0.05).The high-income country group experienced the most substantial price drop(β=-0.475,P＜0.01).(4)The supply-side moderating effect analysis indicated that UNICEF's collective bargaining power maintained robustness across diverse market struc-tures,showing no statistically significant attenuation despite increases in market concentration(interac-tion term β=0.095,P＞0.10).Conclusion:Institutionalized pooled procurement mechanisms are ca-pable of significantly reducing vaccine prices.For those countries that are currently in the immunization financing transition period,as well as those facing high self-procurement benchmark prices,participating in an efficient international pooled procurement platform serves as a critical institutional arrangement to replace external financial aid and to effectively maintain the long-term affordability of vaccines.