Phase I (single-center): The investigators will administer CoV-2-STs in a dose escalation regimen of 2 dose levels (DL1: 1,5x10^7 CoV-2-STs in total; DL2: 2x10^7 CoV-2-STs/m^2). 3 patients will be treated at each dose level (traditional 3+3 design) following by a 12-day wait period to assess safety of the infusions prior to escalating the next dose level (maximum 12 patients). The maximum tolerated dose will be determined Phase II (multicenter): Randomization 2:1, 60 patients will receive the standard of care (SOC) plus CoV-2-STs (ARM A) at the optimum dose which will be determined in phase I and 30 patients will receive only SOC (Arm Β) Phase II (multicenter, extension): Randomization 2:1, 53 patients will be enrolled in Arm A to receive SOC and up to two doses of COV-2-STs and 27 patients will receive only SOC.~Randomization: Patients who meet the eligibility criteria after signing the informed consent form they will randomly be assigned at 2:1 ratio to each of the 2 treatment groups. Patients assigned to arm A will be HLA-typed for HLA-A, B and DRB1 within 24h, and a suitable for them T cell product will be selected from the cell bank. If a suitable product is found, they will continue to arm A, otherwise, they will be assigned to arm B.~Objectives:~i) To determine the feasibility of establishing a bank with GMP-compliant generated SARS-CoV-2 specific T-cells (CoV-2-STs), well-characterized in terms of specificity, phenotype and expression of human leucocyte antigens (HLA), which will be produced by 30 COVID-19 recovered donors with broad HLA diversity in order to be suitable for administration to at least 90 COVID-19 patients ii) To determine the safety of CoV-2-ST administration as cellular immunotherapy in COVID-19 patients, who meet specific inclusion criteria iii) To determine the efficacy of CoV-2-ST administration as cellular immunotherapy in COVID-19 patients, who meet specific inclusion criteria
Open-label phase I (single-center)/ phase II (multicenter) with randomization 2:1