Immunity and safety of Covid‐19 synthetic minigene vaccine  Biological: injection and infusion of LV‐SMENP‐DC vaccine and antigen‐specific CTLs  China/COVID‐19  100, all, 6 months to 80 years  Treatment  Experimental: pathogen‐specific DC and CTLs patients will receive approximately 5 × 106 LV‐DC vaccine and 1 × 108 CTLs via subcutaneous injections and iv infusions, respectively  I
II  Primary:
Clinical improvement based on the 7‐point scale (28 days after randomization), lower Murray lung injury score (7 days after randomization)
Secondary (0–28 day): 28‐day mortality, duration of mechanical ventilation, duration of hospitalization, proportion of patients with negative RT‐PCR results (7 and 14 days after randomization), proportion of patients in each category of the 7‐point scale (7, 14, and 28 days after randomization), proportion of patients with normalized inflammation factors (7 and 14 days after randomization), frequency of vaccine/CTL events, frequency of serious vaccine/CTL events  NCT04276896/Recruiting, Mar24‐Dec31 2020–2024