Risk-driven responses to COVID-19 eliminate the tradeoff between lives and livelihoods

Rahmandad, H.; Lim, T. Y.

Background- Responses to COVID-19 pandemic are conditioned by a perceived tradeoff between saving lives and paying the economic costs of contact-reduction measures. We develop and test the hypothesis that when populations endogenously respond to risk this tradeoff disappears. Methods- We develop a model of SARS-CoV-2 transmission where populations endogenously reduce contacts in response to risk of death. We estimate the model for 118 countries constituting 7.05 billion people and assess the existence of a tradeoff between saving lives and livelihoods. Results- We show that with endogenous responses communities go through three phases: rapid early outbreaks, control through initial response, and a longer period of quasi-equilibrium endemic infection with effective reproduction number (Re) fluctuating around one. Analytical characterization of this phase shows little tradeoff between contact reduction levels (underpinning economic costs) and death rates. Empirically estimating the model, we find no positive correlation (r = -0.241, p = 0.009) between (log) death rates and (normalized) contact levels across nations. While contact reduction levels are broadly similar across countries (5-95 percentile: 0.521-0.867 of pre-pandemic contacts), expected death rates vary greatly, by over two orders of magnitude (5-95 percentile: 0.03-17 deaths per million per day). Interpretation- Whether by choice or by the force of crippling death tolls, most societies will bring down interactions enough to contain SARS-CoV-2s spread. What we control is the severity of death toll required to compel us to act: greater responsiveness to risk can bring down deaths with no excess economic costs.