It is well recognized that population heterogeneity plays an important role in the spread of epidemics. While individual variations in social activity are often assumed to be persistent, i.e. constant in time, here we discuss the consequences of dynamic heterogeneity. We integrate the stochastic dynamics of social activity into traditional epidemiological models . The overall epidemic dynamics is condensed to three differential equations and is characterized by an emergent long timescale . Our model captures multiple features of real-life epidemics such as COVID-19, including prolonged plateaus and multiple waves . Individual waves are suppressed at the state of Transient Collective Immunity (TCI), which subsequently degrades due to the dynamic nature of social activity. Our results also provide a new mechanism for emerging pathogens to transition from a fast-paced epidemic  to the endemic state.
It is well recognized that population heterogeneity plays an important role in the spread of epidemics. While individual variations in social activity are often assumed to be persistent, i.e. constant in time, here we discuss the consequences of dynamic heterogeneity. By integrating the stochastic dynamics of social activity into traditional epidemiological models we demonstrate the emergence of a new long timescale governing the epidemic in broad agreement with empirical data . Our model captures multiple features of real-life epidemics such as COVID-19, including prolonged plateaus and multiple waves , which are transiently suppressed due to the dynamic nature of social activity. The existence of the long timescale due to the interplay between epidemic and social dynamics provides a unifying picture of how a fast-paced epidemic typically will transition to the endemic state.
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. The overall epidemic dynamics is condensed to three differential equations and is characterized by an emergent long timescale
we demonstrate the emergence of a new long timescale governing the epidemic in broad agreement with empirical data
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. Individual waves are suppressed at the state of Transient Collective Immunity (TCI), which subsequently degrades
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Our results also provide a new mechanism for emerging pathogens to transition from a
The existence of the long timescale due to the interplay between epidemic and social dynamics provides a unifying picture of how a
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typically will transition