4.2.2  Rationale: IVIG might help to improve the outcome of patients with COVID-19
The study [23] included ten patients with COVID-19 who demonstrated worsening symptoms, e.g., decreased lymphocyte count and decreased PaO2/FIO2 ratio and oxygen saturation, following treatment with a short-term moderate-dose corticosteroid (methylprednisolone 80 mg/d) plus immunoglobulin (10 g/d). After switching to the double dose of 1600 mg/d methylprednisolone plus 20 g/d immunoglobulin, all of the patients improved in the clinical, laboratory, and paraclinical outcomes.
Passive immunization protects against disease, and so it should be administered as early as possible when the patient is diagnosed. Studies show that the viral RNA of 2019-nCoV reaches its peak during the first week and then gradually decreases and that IgG and IgM begin to rise from the 10th day so that most patients have anti-viral antibodies by the 14th day.