COVID-19 Research: Herd Immunity and Vaccination Game

Photo by CDC on Unsplash

Photo by CDC on Unsplash

This article was shared with The World Health Organization due to its potential impact on the development of some new policies to deal with the COVID-19.


Wooyoung Lim (HKUST) and Pengfei Zhang (Cornell)


Would the affected communities voluntarily obtain herd immunity if a cure for COVID-19 was available? This paper experimentally investigates people’s vaccination choices in the context of a nonlinear public good game. A “vaccination game” is defined in which costly commitments (vaccination) are required of a fraction of the population to reach the critical level needed for herd immunity, without which defectors are punished by the natural contagion of epidemics. Our experimental implementation of a vaccination game in a controlled laboratory setting reveals that endogenous epidemic punishment is a credible threat, resulting in voluntary vaccination to obtain herd immunity, for which the orthodox principle of positive externalities fails to account. The concave nature of the infection probability plays a key role in facilitating the elimination of an epidemic.


Lim W, Zhang P (2020) Herd immunity and a vaccination game: An experimental study. PLoS ONE 15(5): e0232652. https://doi.org/10.1371/journal.pone.0232652

The Paper

Read this manuscript published on May 14, 2020 on PLOS ONE.