全球疫苗集中采购的价格效应

Price effects of global vaccine pooled procurement

摘要

目的：评估以联合国儿童基金会（United Nations Children＇s Fund，UNICEF）和泛美卫生组织（Pan Ameri-can Health Organization，PAHO）为代表的国际集中采购机制对疫苗价格的影响。方法：基于2013—2024年188个国家的14497条疫苗采购交易记录，采用高维固定效应模型与事件研究法识别价格效应及动态趋势，并进行多维异质性分析。结果：（1）基准模型表明，相比单一国家的自主采购，通过 UNICEF 进行集中采购的疫苗价格平均显著降低 $27.6\mathrm{\%}\text{ }(\mathit{\beta }=-0.323,\text{ }\mathit{P}<0.01)\text{ }$ ；PAHO 机制同样显示出约 30.9% 的初步降价潜力（$\beta=-0.370, ~ P=$0.052）。（2）事件研究法严格验证了平行趋势假设（事前系数联合显著性检验 F=0.27,P=0.845），动态追踪显示，在由自主采购转换为集中采购的当年，即可实现约 30.0% 的价格降幅（β=-0.356,P<0.01），且该降价效应在后续年份中保持持续稳定。（3）异质性检验揭示，集中采购具有显著的＂扶弱＂效应，即小规模买家获得的降价幅度（$38.5\mathrm{\%},\mathit{\beta }=-0.487,\mathit{P}<0.01$）显著高于大规模买家（$22.5\mathrm{\%},\mathit{\beta }=-0.255,\mathit{P}<0.01$）；非全球疫苗免疫联盟（Global Alliance for Vaccines and Immunization，GAVI）援助国家的边际降价系数（β=-0.418,P<0.01）远大于GAVI 受援国（β=-0.118,P<0.05）；高收入国家组的降幅最大（β=-0.475,P<0.01）。（4）供给侧调节效应分析表明，UNICEF 的集体议价能力具备跨市场结构的鲁棒性（robustness），未因市场集中度的上升而发生统计学意义上的显著衰减（交互项 β=0.095,P>0.10）。结论：制度化集中采购能够显著降低疫苗价格；对处于免疫规划融资转型期及面临高自主采购基准价的国家，加人高效的国际集中采购平台是替代外部资金援助、维持疫苗长期可负担性的重要制度安排。

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 14497 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 $30.0\mathrm{\%}(\mathit{\beta }=-0.356,\mathit{P}<0.01)$ 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 $(38.5\mathrm{\%},\mathit{\beta }=-0.487,\mathit{P}<0.01)$ 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.

关键词

疫苗 / 集中采购 / 成本及成本分析 / 全球健康 / 市场结构

Key words

Vaccines / Pooled procurement / Costs and cost analysis / Global health / Market structure

参考文献

[1] Lindstrand A, Cherian T, Chang-Blanc D, et al. The world of im- munization:Achievements,challenges,and strategic vision for the next decade[J]. J Infect Dis, 2021, 224(12Suppl 2):S452- S467.

[2] Ozawa S, Grewal S, Portnoy A, et al. Funding gap for immuniza- tion across 94 low-and middle-income countries[J]. Vaccine, 2016, 34(50):6408-6416.

[3] Al-Eitan LN, Almahdawi DL, Abu Khiarah RA, et al. Bridging gaps in vaccine access and equity:A middle eastern perspective[J]. Vaccines, 2025, 13(8): 806.

[4] Hussain R, Bukhari NI, Ur Rehman A, et al. Vaccine prices:A systematic review of literature[J]. Vaccines(Basel), 2020, 8 (4): 629.

[5] Danzon PM, Pereira NS, Tejwani SS. Vaccine supply:A cross- national perspective[J]. Health Aff, 2005, 24(3):706-717.

[6] Plotkin S, Robinson JM, Cunningham G, et al. The complexity and cost of vaccine manufacturing:An overview[J]. Vaccine, 2017, 35(33):4064-4071.

[7] Forslid R, Herzing M. On the optimal production capacity for in- fluenza vaccine[J]. Health Econ, 2015, 24(6):726-741.

[8] Agarwal R, Reed T. Financing vaccine equity:Funding for day- zero of the next pandemic[J]. Oxf Rev Econ Policy, 2022, 38 (4):833-850.

[9] Engle-Warnick J, Ruffle BJ. Buyer concentration as a source of countervailing power: Evidence from experimental posted-offer markets[J/OL]. J Behav Exp Econ, 2005.[ 2025-11-29].

[10] Kim SW, Skordis-Worrall J. Can voluntary pooled procurement re- duce the price of antiretroviral drugs?A case study of Efavirenz [J].Health Policy Plan, 2017, 32(4):516-526.

[11] Wang LX, Bin Zahur N. Procurement institutions and essential drug supply in low and middle-income countries[J]. J Health Econ, 2025, 101: 102996.

[12] Danzon PM, Mulcahy AW, Towse AK. Pharmaceutical pricing in emerging markets:Effects of income,competition,and procure- ment[J]. Health Econ, 2015, 24(2):238-252.

[13] Seidman G, Atun R. Do changes to supply chains and procure- ment processes yield cost savings and improve availability of phar- maceuticals,vaccines or health products?A systematic review of evidence from low-income and middle-income countries[J]. BMJ Glob Health, 2017, 2(2):e000243.

[14] Li L. Price discrimination and bargaining power in the global vac- cine market[D]. Durham: Duke University, 2013.

[15] Cernuschi T, Gilchrist S, Hajizada A, et al. Price transparency is a step towards sustainable access in middle income countries[J]. BMJ, 2020, 368: 15375.

[16] Dubois P, Lefouili Y, Straub S. Pooled procurement of drugs in low and middle income countries[J]. Eur Econ Rev, 2021, 132: 103655.

[17] Huff-Rousselle M. The logical underpinnings and benefits of pooled pharmaceutical procurement:A pragmatic role for our pub- lic institutions?[J]. Soc Sci Med, 2012, 75 (9):1572-1580.

[18] Cernuschi T, Furrer E, Schwalbe N, et al. Advance market com- mitment for pneumococcal vaccines:Putting theory into practice[J]. Bull World Health Organ, 2011, 89(12):913-918.

[19] Sriudomporn S, Watts E, Yoon Sim S, et al. Achieving immuni- zation agenda 2030 coverage targets for 14 pathogens:Projected product and immunization delivery costs for 194 countries, 2021 - 2030 [J]. Vaccine X,2022, 13: 100256.

[20] Rochlin DH, Rizk NM, Matros E, et al. Negotiated rates for sur- gical cancer care in the era of price transparency-prices reflect market competition[J]. Ann Surg, 2024, 279(3):385-391.

[21] Balli HO, Sørensen BE. Interaction effects in econometrics[J]. Empir Econ, 2013, 45(1):583-603.

[22] Schmidheiny K, Siegloch S. On event studies and distributed-lags in two-way fixed effects models:Identification,equivalence,and generalization[J]. J Appl Econom, 2023, 38(5):695-713.

[23] Gilmore AB, Fabbri A, Baum F, et al. Defining and concep- tualising the commercial determinants of health[J]. Lancet, 2023, 401(10383):1194-1213.

[24] Saxenian H, Alkenbrack S, Attaran MF, et al.Sustainable finan- cing for immunization agenda 2030

[25] [ J . Vaccine, 2024, 42(Suppl 1):S73-S81.]

[26] Parmaksiz K, Pisani E, Bal R, et al. A systematic review of pooled procurement of medicines and vaccines:Identifying ele- ments of success[J]. Global Health, 2022, 18(1): 59.