* 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.)

* 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.)

- 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.)

- 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.)