a, The temporal trajectory of COVID-19 is generally divided into four stages in survivors, which includes the presymptomatic (S1), hyperinflammatory (S2), resolution (S3) and convalescent (S4) phases. The first half of the trajectory (that is, SARS-CoV-2 RNA positive) is largely virus driven, characterized by immunosuppression and the response of the host to the invading pathogen, whereas the second half comprises mainly host-driven metabolism to resolve the hyperinflammation and restore physiological homeostasis. Exosome-enriched EVs were isolated from fasting plasma, and high-coverage analyses of exosomal lipidome with a focus on sterols and oxysterols were conducted. b, The particle size distribution of isolated EVs. n = 4 independent experiments. c, Particle sizes of isolated EVs analysed by nanoscale flow cytometry. Representative plot from n = 4 independent experiments.