Paxlovid for Treatment of Long Covid

Not Recruiting

Trial ID: NCT05576662


The purpose of this study is to compare whether being treated with Paxlovid (nirmatrelvir plus ritonavir) for 15 days works better than being treated with placebo (plus ritonavir) to reduce severe symptoms of Long Covid (the placebo does not have any active drug). Participants will have 5 planned visits to the study clinic over 15 weeks and will take the drug (or placebo) for the first 15 days. This study uses the term post-acute sequelae of SARS-CoV-2 (PASC), which is another name for "Long Covid."

Official Title

Selective Trial Of Paxlovid for PASC (STOP-PASC): Randomized Double-Blind Placebo-Controlled Pilot Trial of Paxlovid for the Treatment of PASC

Stanford Investigator(s)

Linda N. Geng, MD, PhD
Linda N. Geng, MD, PhD

Clinical Associate Professor, Medicine - Primary Care and Population Health

Upinder Singh
Upinder Singh

Stanford Medicine Professor of Infectious Disease and Professor of Medicine (Infectious Diseases & Geographic Medicine) and of Microbiology and Immunology


Inclusion Criteria:

   - Normal or near-normal kidney function

   - History of confirmed COVID-19 infection that preceded the post-COVID symptoms

   - Post-COVID-19 symptoms persisting greater than three months

   - At least 2 post-COVID symptoms of moderate or severe intensity (fatigue, brain fog,
   shortness of breath, body aches, gastrointestinal symptoms, or cardiovascular

   - Willing to report all vaccinations

   - Women of childbearing potential or men whose partners may become pregnant must use
   acceptable method of contraception during the treatment period and for 28 days after
   the last dose of the study drug

   - Willing and able to adhere to study procedures and available for the duration of the

Exclusion Criteria:

   - Suspected or confirmed pregnancy or breastfeeding

   - Severe liver disease

   - Prior use of study drug or other COVID treatment within 30 days

   - Hypersensitivity or other contraindication to any components of the study drug

   - Current or expected use of any medication dependent on or inducer of CYP3A4

   - Current or expected use of supplements or herbs (unless medically necessary) that
   cannot be temporarily held (period as determined necessary by investigators)

   - HIV infection with viral load >50 copies/ml

   - Suspected or confirmed active COVID infection within 30 days

   - History of COVID vaccine within 28 days prior to enrollment, or other vaccine
   (influenza, shingles, etc.) within 14 days of enrollment, or planned use of any
   vaccine until the primary endpoint has been met (10 weeks)

   - Other medical condition(s) or concomitant therapy that would compromise participant's
   safety or compliance with the study protocol or significantly confound interpretation
   of study results, as determined by study investigators

   - Current enrollment in, or discontinuation within the last 30 days from, a clinical
   trial involving any investigational drug or device

   - Inability to provide informed consent

   - Currently hospitalized


drug: Nirmatrelvir

drug: Placebo

drug: Ritonavir

Not Recruiting

Contact Information

Stanford University
School of Medicine
300 Pasteur Drive
Stanford, CA 94305
Study Team