Zofin to Treat COVID-19 Long Haulers

This is a phase I/II randomized, double blinded and placebo control. COVID-19 Long Haulers In double blinded and placebo control trial, neither the patients nor the researchers know who is getting a placebo and who is getting the treatment. The ratio between groups is 1:1 for total 30 subjects. Each subject will be randomized to receive either treatment or placebo. A total of 30 subjects will be enrolled and randomized. Group 1 (15 subjects) Fifteen subjects will receive 1 mL of Zofin diluted with 100ml of sterile saline on day 0, day 4 and day 8, containing 2-5 x 10\^11 particles/ml intravenously. Group 2 (15 subjects) Fifteen subjects will receive 1mL of placebo diluted with 100ml of sterile saline on day 0, day 4 and day 8, containing sterile saline intravenously.