Fig. 1.

conceptualizes an interaction model of frailty and resilience into four different phenotypes, namely “fit and resilient”, “fit and non-resilient”, “frail and resilient” and “frail and non-resilient” in comparison to a healthy aging trajectory. Fig. 1A shows the impact of COVID stress in initially fit individuals. The first scenario describes Fit and resilient people who are able to regain the pre-COVID health status in a relatively short period of time (Fig. 1A-2). The Fit and non-resilient phenotype represents the subset of individuals in which the acute COVID stress leads rapidly to disability with dramatic change in the initial optimal health condition (Fig. 1A-3). Fig. 1B shows the impact of COVID stress in initially frail individuals. The Frail and resilient phenotype comprises individuals who were frail before COVID onset, but with preserved resilience (Fig. 1B-4). The last scenario depicts frail and non-resilient phenotype, represents the most vulnerable individuals in which COVID stress makes them rapidly develop irreversible disability (Fig. 1B-5). Abbrevations: PACS – post acute COVID-19 syndrome.