The `greed ́ and `nationalism ́ in vaccination against Covid-19 lead to the Tragedy of the Commons, Nash equilibrium and Giffen's goods, giving SARS-CoV-2 more opportunities to escape mutants.

Abstract

It is possible to follow an ideal vaccination global strategy, that will reduce to the minimum the number of infected and dead by COVID-19 as well as the likelihood of an escape mutant. This ideal vaccination strategy needs of a high degree of international cooperation among different countries. International initiatives as COVAX, advocated by the WHO, try to achieve such goal. However, in the present scenario with limited number of vaccine doses, Game Theory model also predicts that they are becoming goods subject to the Tragedy of the Commons. Countries with the capability to control vaccine dose distribution will desert from the international agreements, vaccinating first to their own nationals. If such behaviour is known by other countries (as is happening now) more countries will be tempted to desert as well. Eventually it will end in a Nash equilibrium, which stops the ideal vaccination strategy. Furthermore, in poorer countries, with great difficulties to get access to vaccine doses, these will be transformed into Giffen goods. Vaccination data available to date, show that we are in a scenario where vaccine doses have transformed into goods subject to the Tragedy of the Commons, countries desert from cooperation reaching a Nash equilibrium and vaccine doses are close to become a Giffen good for the poorer countries. This dynamic will not only rise the number of infected and dead by COVID-19, but also the likelihood of an escape mutant (in the SARS-CoV-2 populations) will be increased. If, eventually, this turns out to be the new scenario new vaccines could be developed for those new escape mutant strains, going back to a very similar setting as the starting one. Most likely, the world will reach a Pareto optimality (equilibrium between desertion and cooperation) due the pressure of those who seek high levels of cooperation to attain a global vaccination strategy.