Fig. 3: Vaccination-related benefits of three groups under different global vaccine-distribution strategies and the potential incentives (i.e., multilateral benefit-sharing mechanism) to promote a more equitable distribution.

a Shows flows of money and vaccines without any benefit-sharing mechanism; b shows the benefits of the three groups of countries without any benefit-sharing mechanism; c shows flows of money and vaccines with a benefit-sharing mechanism; d shows the new situation (payoffs of the three groups of countries under different distribution strategies) with a benefit-sharing mechanism. The yellow money symbol in (a, c) indicates money used to buy vaccines and the blue vaccine symbol in (a, c) indicates vaccines purchased. The red money symbol with a hand below in (c) indicates money donations, and red vaccine symbol with a hand below in (c) indicates vaccine donations. The “Producer-first” and “Balanced” in (b, d) represent the “Producer-first Distribution Strategy” scenario and “Balanced Distribution Strategy” scenario. The number on the horizontal bars in (b, d) indicates vaccination-related benefits (expressed in trillion US dollars). The light red horizontal bars in (d) represent the aids from high-income countries to promote a more equitable distribution of vaccines around the world. The “Oldest First” and “High risk” scenario is the default scenario in this comparison.