The host response to COVID-19 pathophysiology over the first days of infection remains largely unclear especially the mechanisms in the blood compartment. We report here on a longitudinal proteomic analysis of acute phase COVID-19 patients, for which we used blood plasma and MRM proteomics with internal standards as well as DIA. We measured samples on admission for 49 patients, of which 21 with additional samples on days 2, 4, 7, and 14 after admission. We also measured 30 externally obtained samples from healthy individuals for comparison at baseline.