Decline in mitigation readiness facilitated second waves of SARS-CoV-2

Societal responses crucially shape the course of a pandemics but are difficult to predict. Mitigation dynamics is introduced here as an integral part of an epidemiological model, which is applied to the ongoing SARS-CoV-2 pandemic. Unperturbed simulations accurately reproduce diverse epidemic and social response trajectories from 2020 to 2021 reported from 11 European countries, Iran, and 8 US states. High regional variability in the severity and duration of the spring lockdown and in peak mortality rates of the first SARS-CoV-2 wave can be explained by differences in mitigation readiness <I>H</I> which is here mathematically defined as the value of human lives in relation to business-as-usual contact rates. <I>H</I> entails a suite of political, social, and psychological aspects of decision making. The simulations also suggest that a subsequent decrease in <I>H</I> much intensified the second wave and slowed down its decay. With less effective lockdowns, vaccination became the primary mitigation strategy in 2021. Retardation of vaccination relative to a 3-month scheme is projected to provoke an average toll of 1.5 deaths per million and delayed day. This toll particularly rises in regions with high numbers of old and still susceptible people, which is relevant for revising current policies of vaccine distribution.