The objective of this study is to evaluate the efficacy and safety of 5131A for hospitalized patients of COVID-19.

Inclusion Criteria:

• The COVID-19 patient who diagnosed by PCR within 3 days prior to randomized And who is hospitalized with COVID-19 related symptoms
• The subject who has symptoms of COVID-19 within 7 days
• The subject with pneumonia confirmed by imaging diagnosis related to COVID-19 OR a 70-year-old or older OR 60-year-old or older with underlying disease (diabetes or hypertension or obesity or smoker)
• Willing and able to provide written informed consent prior to performing study procedures

Exclusion Criteria:

• asymptomatic patient
• The subject who requiring mechanical ventilation or ECMO
• The subject who are underlying oxygen therapy before affected by COVID-19
• The subject who have received antiviral drugs for other disease within 4 weeks
• History of allergy to IVIG or plasma products
• The subject who received IVIG or convalescent plasma from a person who recovered from COVID-19
• IgA deficiency
• Cretinine > 2 X ULN
• The subject with a history of thrombosis or high risk of thromboembolism
• The subject with reduced heart function [NYHA (New York Heart Association) Functional Class III or IV]; or cerebral cardiovascular disorder or a patient with the medical history (ischemic disease, cardiovascular disease, cerebrovascular disorder, blood vessel disorder, etc.)