Introduction: Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was declared a public health emergency of international concern (PHEIC) by the WHO. ZF2001, a protein subunit vaccine targeting the RBD, was utilized to evaluate its impact on the immune system of COVID-19 patients. This study aimed to investigate peripheral cell profiles one year after three doses of ZF2001 vaccine using single cell mass spectrometry flow cytometry (CyTOF), a technique that allows detailed characterization of the immune response against SARS-COV-2 infection and further evaluation of ZF2001 mechanisms as a prophylactic against chronic disease and reducing mortality. Methods: This study profiled peripheral blood mononuclear cells (PBMCs) from 16 vaccinated COVID-19 patients (Omicron 5.2) and 8 hDs using CyTOF with a 41-antibody panel. PBMCs isolated via Lymphoprep density gradient underwent metal-tagged antibody staining. Data analysis included FlowJo gating, Seurat/Harmony batch correction, PhenoGraph clustering (k=45), and t-SNE visualization. Statistical assessments employed Wilcoxon tests and Spearman correlation. Results: Our findings revealed significant differences between infected and healthy individuals one year after three doses of ZF2001. Specifically, infected individuals exhibited: significant elevation of cytotoxic T cells expressing CD8 with a proliferation marker antigen-Kiel 67 (Ki67) and an adhesion molecule (CD138), expansion of B cells and reduction of monocytes expressing CD16, as well as depletion of CD4+ T cells and differentiation of T cells 1 year after the vaccine. These changes suggested that the vaccine was effectively modulating the immune response. Discussion: Our results provided a detailed single-cell profile of the immune response to SARS-CoV-2 infection in vaccinated patients, highlighting significant changes in immune cell kinetics indicative of an active innate and adaptive immune cell response.