Phase I Open-Label Safety Trial of Pembrolizumab for Neurological Post- Acute Sequelae of SARS-CoV-2 (PD1-PASC I)

Background: SARS-CoV-2 is the virus that causes COVID-19. Some people who recover from an acute COVID-19 infection may continue to have symptoms that persist for months or years. These can include neurological symptoms, such as headaches, loss of taste or smell, dizziness, or trouble walking. Pembrolizumab is a drug approved to treat certain cancers. Researchers think this drug might reduce long-term neurologic symptoms after a COVID-19 infection. Objective: To test pembrolizumab in people with ongoing neurologic symptoms of COVID-19. Eligibility: People aged 18 years or older who had COVID-19 at least 6 months ago and have ongoing neurologic symptoms. Design: Participants will have 7 clinic visits in 7 months. Participants will be screened. They will have a physical exam with blood tests. Swabs will be used to collect cells from inside the mouth and nose. They may opt to have an imaging scan. Participants will also have other tests before they are given the study drug. These include eye and skin exams; tests of their memory and thinking; and tests of involuntary body functions, such as heart rate, blood pressure, sweating, and digestion. Their grip strength and walking pace will be measured. They will wear a heart rate monitor for 24 hours. They will wear devices on a wrist and thigh to measure activity for 10 days. Participants will have a lumbar puncture (spinal tap): A thin needle will be inserted into their lower back to draw out a sample of the fluid around their spinal cord. Pembrolizumab is given through a needle inserted into a vein. Participants will receive 1 dose of the drug. Participants will have 4 follow-up visits over 6 months. Tests may be repeated during these visits.