Supply chains create global benefits from improved vaccine accessibility

The paper addresses persistent global inequities in COVID-19 vaccine access, which undermine pandemic control and economic recovery. Despite initiatives like ACT-Accelerator/COVAX, coverage remains around 10% in many low-income countries. Recurrent SARS-CoV-2 variants, global supply-chain interdependence, and cross-border externalities from vaccination motivate investigating how alternative global allocation strategies affect health and economic outcomes. The study poses three core questions: (1) How should vaccines be distributed among countries? (2) How should vaccines be distributed among age groups? (3) How should vaccines be distributed among industrial sectors? To answer these, the authors link an age-stratified epidemiological model with a global economic model to quantify benefits from different global and domestic vaccination strategies, emphasizing health gains, lockdown easing, and supply-chain rebuilding effects.

The article situates its contribution within research showing that pandemic control measures (e.g., lockdowns) generate economic impacts that propagate internationally through supply chains, highlighting vaccination as a source of positive externalities. It references empirical and modeling studies on COVID-19 transmission, economic implications of the pandemic, vaccination externalities and valuation, supply-chain shock propagation, and input–output-based disaster impact models (e.g., ARIO). These works underscore that market-driven vaccine allocation neglects cross-border spillovers, justifying coordinated, equitable distribution mechanisms to achieve socially optimal outcomes.

The study designs a tiered scenario framework combining global allocation rules, age priorities, and sectoral workforce priorities. Global scenarios include: Producer-first Distribution (vaccine-producing countries vaccinate domestically before sharing), Balanced Distribution (vaccines pooled and allocated by population), and Balanced Age-informed Distribution (pooled allocation weighted by elderly population shares). Domestic age priorities consider Oldest-first (≥65), Youngest-first (<65), and Uniform. Sectoral priorities include High risk (by exposure risk) and Critical (by essential worker share) versus Equal across sectors. Vaccine production capacity for seven major producers (China, USA, Germany, India, UK, Netherlands, Russia) is projected using UNICEF data and a logarithmic growth fit, assuming invariant relative shares across countries. Epidemiology: a realistic age-stratified multi-compartment SEIR model (16 age groups) parameterized with country-specific demographics and social contact matrices, R0≈3.5, incubation ~2.5 days, infectious period ~7 days, waning immunity, and vaccine efficacy of 50%. Vaccination modifies effective susceptibility after an average 10-day delay; coverage and rollout scenarios are applied to compute averted mortality. Health gains are monetized via the Value of a Statistical Life (VSL), using a U.S. baseline (USD 11M, 2019) adjusted by income elasticity (1.0) for country-specific VSL and a uniform global VSL (USD 2.94M) for equity-sensitive reporting. Lockdown strictness is inferred from Google Community Mobility Reports (supplemented for missing countries), linking vaccination progress to the easing of mobility restrictions. Economic modeling uses a recursive dynamic disaster impact assessment model extending ARIO with substitutions across same-sector products from different regions and supplier choice based on capacity. The model operates on GTAP 10 MRIO (141 regions, 65 sectors), tracking production, allocation (proportional rationing), demand (inventory targets), inventories, and propagation of shocks. Two simulations are compared: (i) counterfactual no-vaccine world to estimate losses (direct lockdown and propagated supply-chain impacts), and (ii) each vaccine-distribution scenario. Benefits are defined as reduced losses: lockdown-easing benefit (difference in direct loss components) and supply-chain rebuilding benefit (difference in propagated losses). Uncertainty analyses vary vaccine production pathways and model parameters to assess distributions of health, lockdown, and supply-chain benefits.

• Global benefits: More equitable global allocation increases total benefits relative to Producer-first. Estimated total annual benefits from vaccination are about $8.65 trillion under Balanced Distribution and $9.05 trillion under Balanced Age-informed Distribution, compared to a lower baseline under Producer-first, implying an 11.7% global increase (≈$950 billion/year) with age-informed equity.
• Decomposition of gains: Relative to Producer-first, Balanced increases health gains by 1.8% and Balanced Age-informed by 7.0%. Lockdown-easing effects increase overall by about 1.1% under Balanced Age-informed. Supply-chain rebuilding benefits increase substantially: +67.4% (Balanced) and +74.7% (Balanced Age-informed).
• Country illustrations: Health gains in Mozambique rise from 9.5% to 13.3% of annual GDP under Balanced Age-informed. In Peru, lockdown-easing benefits increase from 6.4% to 12.3% of GDP when moving from Producer-first to Balanced. Spain’s lockdown-easing benefits are 6.3% of GDP under Balanced Age-informed and markedly higher than under Producer-first; spillovers benefit trading partners like Portugal.
• Domestic prioritization by age: Prioritizing the elderly yields higher total benefits than prioritizing younger groups. In the USA, total benefits are ~7.5% (7.2–8.1%) of GDP with elderly-first vs ~7.2% (6.9–7.9%) with younger-first; health gains are 1.1% of GDP with elderly-first vs 0.2% with younger-first.
• Sectoral prioritization: After vaccinating the elderly, prioritizing high-exposure-risk workforce yields larger lockdown-easing and supply-chain benefits than equal or purely “critical” sector strategies. For the USA, the lockdown-easing effect is 4.6% of GDP with high-risk prioritization versus 2.2% with equal allocation across sectors. Prioritizing high-risk sectors generates 0.1–10.9% extra spillover benefits compared with equal sectoral allocation.
• Supply-chain spillovers: In tightly connected economies, sectoral spillovers are strong. Under High-risk prioritization, benefits to the Grains and Crops sector increase by 15.2% (USA) and 23.6% (Germany) relative to equal sectoral allocation; in emerging economies spillover gains are smaller (e.g., Vietnam 11.9%, Brazil 6.6%).
• Cooperation incentives: Without benefit-sharing, producers prefer Producer-first (e.g., producer benefits: $5.31T under Producer-first vs $4.58T under Balanced), while high- and low-income non-producers gain under Balanced (e.g., high-income: $2.23T to $3.23T; low-income: $0.65T to $0.94T). A multilateral benefit-sharing mechanism can achieve a Pareto improvement: high-income non-producers could share up to $0.87T of additional benefits; transfers >$0.73T would make producers prefer Balanced, while costs <$0.10T still leave donors better off than under Producer-first.

Findings show that equitable international vaccine allocation amplifies global benefits by leveraging health protection and especially supply-chain externalities. Sharing vaccines earlier with non-producer countries—particularly targeting the elderly and high-exposure workers—reduces mortality, relaxes mobility restrictions, and accelerates the restoration of cross-border production networks. Despite aggregate efficiency gains, unilateral incentives lead producers to favor domestic-first policies. A multilateral benefit-sharing mechanism—where high-income non-producers compensate producers and support capacity building in lower-income countries—can realign incentives and achieve Pareto improvements. Domestically, vaccinating the elderly first maximizes health gains and overall benefits, and subsequently prioritizing high-exposure sectors accelerates recovery and creates strong inter-sector spillovers. By quantifying the supply-chain rebuilding benefits alongside health gains and lockdown easing, the study provides a fuller accounting that can mitigate political resistance to sharing vaccines and underscores that equity can also be efficient.

The study integrates age-structured epidemiology with a dynamic global IO-based disaster impact model to assess health and economic benefits of alternative vaccine allocation strategies. It demonstrates that equitable, age-informed global sharing increases annual benefits by roughly 11.7% (~$950B) relative to producer-first policies, largely via supply-chain rebuilding effects, and that domestic prioritization of the elderly followed by high-exposure sectors yields the greatest overall gains. A feasible multilateral benefit-sharing mechanism can realign incentives so all country groups benefit from equitable allocation. The framework offers a transferable methodology for future pandemics. Future research should incorporate epidemiology–economy feedbacks, technological and behavioral adjustments, demand-side dynamics and vaccine market competition, and optimization of global production capacity expansion and location for vaccine manufacturing.

• The models lack explicit feedback between epidemiological dynamics and economic behavior, potentially omitting important interactions.
• Assumptions include limited technological change and behavioral adjustment in the short-term focus, which may affect results.
• Analysis is constrained by sector-level trade relationships and does not model vaccine market competition or evolving demand.
• Economic efficiency is not the sole policy criterion; feasibility and demand considerations are outside scope.
• The study does not optimize where to add vaccine production capacity or its timing; such spatial optimization is left for future work.
• Vaccine production capacity projections reflect best estimates at study time; rapid real-world changes introduce uncertainty.