High-resolution mass spectrometry and the parallel quantitative evaluation of thousands of proteins has been used to characterise the proteomes of peripheral blood neutrophils from >200 individuals. This work has comprehensively mapped neutrophil molecular changes associated with mild versus severe COVID19 and identified significant quantitative changes in more than 1700 proteins in neutrophils from patients hospitalised with COVID19 versus patients with non-COVID19 acute respiratory infections. The study identifies neutrophil protein signatures associated with COVID19 disease severity. The data also show that alterations in neutrophil proteomes can persist in fully recovered patients and identify distinct neutrophil proteomes in recovered versus non recovered patients. Our study provides novel insights into neutrophil responses during acute COVID-19 and reveal that altered neutrophil phenotypes persist in convalescent COVID19 infections.