Evaluation of national responses to COVID-19 pandemic based on Pareto optimality

Countries worldwide have adopted various strategies to minimize the socio-economic impact of the ongoing COVID-19 pandemic. Stringency and efficacy of imposed measures vary due to diversity of organizational cultures and ingrained societal practices, but also universally reflect the standpoint from which protecting public health and saving economy are seen as contradictory objectives. We analyzed cumulative deaths per capita and cumulative mobility reduction related to the decrease of economic activity in terms of Pareto optimality to show that as long as epidemic suppression is the aim, the trade-off between the death toll and economic loss is illusory: high death toll correlates with deep lockdown and thus, very likely, with severe economic downturn. We explained this effect by analyzing national epidemic trajectories in the mobility reduction vs. reproduction number (R) plane. When the number of daily new infections is high, mobility reduction is the only way to bring R below 1, but when new infections become sporadic, the epidemic can be suppressed by efficient testing complemented by relatively mild restrictions. South American trajectories suggest that lifting mobility restrictions at R > 1 may ultimately lead to the “herd immunity scenario”, in which transient lockdown only adds economic costs to an inevitably high death toll.