Feb 7, 2026
What concentrations of circulating SARS‑CoV‑2 Spike protein are observed in hospitalized versus mild COVID‑19 patients, and how do those levels compare to doses used in animal experiments?
Circulating (S) protein—measured as soluble S or S1 antigen in plasma—has been reported in the low‑nanogram per milliliter range in patients, with investigators selecting experimental concentrations o...