[Price effects of global vaccine pooled procurement].

Abstract

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 vaccine 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 conducting 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 approximately 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 reduction 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 structures, showing no statistically significant attenuation despite increases in market concentration (interaction term β=0.095, P>0.10).

Conclusion: Institutionalized pooled procurement mechanisms are capable 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.