<p>Taking as a point of departure the role that the category of frailty increasingly plays in the classification, sorting and management of ageing populations in contemporary societies, this paper examines how the onset of Covid-19—as a disease posing the most risk to older adults—affected scientific knowledge production on frailty. Drawing on a theoretically driven network mapping of scientific literature on frailty before and after the pandemic, the paper traces emergent shifts in the evolution of two key discourses of frailty, namely that of the accumulation of deficits and the phenotype, respectively. Our analysis identifies an increased enrolment of frailty as a clinical, prognostic category post-Covid, underpinned by the deficit accumulation model and its key instrument, the frailty index. In parallel, we observe the continuation of laboratory and experimental research on frailty, as aligned with the phenotype approach. We note that in comparison to before Covid, this shift seems to be taking place across a more diversified scientific terrain, with the field of geriatrics playing a central, mediating role between distinct-yet-relational articulations of frailty—those tied to the clinic on one end, and the lab on the other.</p>