Immunotherapy for Neurological Post-Acute Sequelae of SARS-CoV-2

Background: COVID-19 can cause problems in different parts of the body. For most people, it causes fevers or trouble breathing. Some people might not recover all the way. Researchers want to see if a treatment can help with people who have recovered from COVID-19 but still have symptoms ("Long COVID"). Objective: To learn if human immunoglobulin (IVIG) will help with neurological symptoms of Long COVID. Eligibility: Adults ages 18 and older who had COVID-19 at least 12 weeks ago and have ongoing neurologic symptoms, such as dizziness, trouble walking, or problems with strength. Design: Participants will be screened with a medical record review. Participants will have a medical history and a physical exam and complete questionnaires about their health and quality of life. They will have a spinal tap. They will give blood samples. They will discuss their symptoms with a neurologist and have a neurological exam. Participants will take memory and thinking tests using a tablet. The tests will take 1 hour to complete. They will also take a smell and taste test. It will take approximately 30 minutes to complete. Participants will lie on a table that tilts for up to 40 minutes. Their blood pressure and heart rate will be monitored. Blood will be taken through an intravenous (IV) catheter. Participants will receive either IVIG, or saline by IV for 5 days. Then the participants will receive IVIG if they first received saline or saline if they first received IVIG by IV for another 5 days. They will not know what they receive. Participants will have an MRI of the brain if they have not had one recently. They will receive a contrast agent by IV as part of the MRI scan. Participants will be on the study for up to 4 months. They will have follow-up visits at the clinical center as well as fill out questionnaires at home. They may be asked to continue follow-up.

NCT Number	NCT05350774
Lead Sponsor	National Institute of Neurological Disorders and Stroke (NINDS)
Conditions	Systemic Inflammation, Neuroinflammation, Microvascular Thrombosis
Enrollment	45 participants
Start Date	2023-07-10
Primary Completion	2026-12-15 (estimated)
Study Completion	2026-12-15 (estimated)
Updated on ClinicalTrials.gov	2026-08-07