Clinical Research Directory

Inclusion Criteria: * See NCT06305780 for RECOVER-AUTO: Platform Protocol level inclusion criteria which applies to this appendix (or sub-study) Additional Appendix A (IVIG Sub-study) Level Inclusion Criteria: 1. Abnormal active standing test defined as presence of orthostatic tachycardia (an increase of 30 beats per minute (bpm) or more in HR within 10 minutes upon standing without orthostatic hypotension) and experiencing orthostatic symptoms 2. COMPASS-31 Score \> 40 Exclusion Criteria: * See NCT06305780 for RECOVER-AUTO: Platform Protocol level exclusion criteria which applies to this appendix (or sub-study) Additional Appendix A (IVIG Sub-study) Level Exclusion Criteria: 1. Current or previous IVIG treatment 2. Contraindication to intravenous immunoglobulin. 3. Known allergic reactions to blood products including IVIG and/or subcutaneous immunoglobulin (SCIG), such as history of clinically relevant hemolysis after IVIG infusion, aseptic meningitis, recurrent severe headache, hypersensitivity, severe generalized or severe local skin reactions 4. Selective IgA deficiency 5. Current and recent (within 5 half-lives) use of high-dose corticosteroids (for example for prior solid organ transplant), omalizumab, anti-TNF-alpha inhibitors 6. Use of immunosuppressants such as Plaquenil, or low-dose steroid (prednisone, no more than 10mg a day) will be excluded unless the participant is on stable (\>4 weeks) dose 7. Significant thrombotic events after the acute phase of COVID-19 and/or within 6 months of enrollment 8. Veins that are not viable for infusions 9. Not willing to adhere to dosing schedule for IVIG infusions for 9 months