The immune system plays a major role in Coronavirus Disease 2019 (COVID-19) pathogenesis, viral clearance and protection against re-infection. Immune cell dynamics during COVID-19 have been extensively documented in peripheral blood, but remain elusive in the respiratory tract. We performed minimally-invasive nasal curettage and mass cytometry to characterize nasal immune cells of COVID-19 patients during and 5-6 weeks after hospitalization. We also analysed paired whole blood samples using flow and mass cytometry. Contrary to observations in blood, no general lymphocyte depletion at the nasal mucosa could be detected. Instead, we observed increased numbers of nasal granulocytes, monocytes, CD11c+ NK cells and CD4+ T effector cells during acute COVID-19 compared to age-matched healthy controls. These pro-inflammatory responses associated with HLA-DRlow monocytes, CD38+ PD1+ CD4+ T effector cells and plasmablasts in blood, while nasal neutrophils also negatively correlated with oxygen saturation levels. Nasal immune cell numbers mostly normalized following convalescence, except for persisting CD127+ granulocytes and activated T cells, including CD38+ CD8+ tissue-resident memory T cells. Moreover, we identified SARS-CoV-2 specific CD8+ T cells in the nasal mucosa in convalescent patients. Thus, COVID-19 has both transient and long-term effects on the immune system in the upper airway.