To assess the COVID-19-related symptoms using patient-reported outcome measure (PRO) score.;To assess the efficacy of EXO-CD24 in the clinical improvement of COVID-19 disease;To evaluate respiratory failure (defined as the need for mechanical ventilation, ECMO, non-invasive ventilation, or high-flow oxygen devices) rate.;To evaluate the death rate.;To evaluate the safety of EXO-CD24 in the treatment of patients with moderate or severe COVID-19 disease;To evaluate time from hospitalization to hospital discharge.;To evaluate time to improvement and recovery (COVID-19 clinical severity score of 3 or lower).

To assess the COVID-19-related symptoms using patient-reported outcome measure (PRO) score.;To assess the efficacy of EXO-CD24 in the clinical improvement of COVID-19 disease;To evaluate respiratory failure (defined as the need for mechanical ventilation, ECMO, non-invasive ventilation, or high-flow oxygen devices) rate.;To evaluate the death rate.;To evaluate the safety of EXO-CD24 in the treatment of patients with moderate or severe COVID-19 disease;To evaluate time from hospitalization to hospital discharge.;To evaluate time to improvement and recovery (COVID-19 clinical severity score of 3 or lower).