This is an appendix of master protocol (NCT05595369) designed to be flexible so that it is suitable for a wide range of settings within health care systems and in community settings where it can be integrated into COVID-19 programs and subsequent treatment plans.
View on ClinicalTrials.gov ↗Last updated 07 October 2026 from ClinicalTrials.gov. Trial statuses are refreshed automatically; check the registry record for the latest status and contact details.
All interventional trials in our ClinicalTrials.gov extract that list Ritonavir as an intervention, across Long COVID / PASC (3). 0 are currently open to enrolment and 3 have completed. Read the OSMF evidence profile for Ritonavir for literature, mechanism and dosing context.
Intervention names are normalised from the registry's own arm labels, so the same compound can appear under a brand name, a generic name or a combination; check the full agent index for related entries.
Completed (3)
The purpose of this study is to compare whether being treated with nirmatrelvir plus ritonavir for 15 days works better than being treated with placebo plus ritonavir to reduce severe symptoms of Long Covid. 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.
View on ClinicalTrials.gov ↗This decentralized trial is a Phase 2, 1:1 randomized, double-blind, superiority, placebo-controlled study in an anticipated 100 non-hospitalized highly symptomatic adult participants with long COVID. It seeks to determine the efficacy, safety, and tolerability of 15 days of Paxlovid (nirmatrelvir/ritonavir), an anti-viral agent, compared with placebo plus ritonavir.
View on ClinicalTrials.gov ↗Frequently asked questions
How do I join a clinical trial?
Open the trial's ClinicalTrials.gov record (the "View on ClinicalTrials.gov" button), read the Eligibility Criteria and Contacts and Locations sections, and contact the study team listed there. Trials only enrol at the sites shown in the record, so check whether a site is near you or whether the study is remote/decentralised. Your own clinician can help you judge whether a trial is a sensible option and may need to provide medical records.
What do the trial phases mean?
Early Phase 1 / Phase 1 studies test safety and dosing in a small group. Phase 2 studies look for a signal of benefit in a larger group and keep checking safety. Phase 3 studies are large confirmatory trials designed to show whether a treatment works well enough for approval. Phase 4 studies follow approved treatments after they reach the market. "Phase not applicable" is used by the registry for behavioural, device, rehabilitation and other non-drug interventions.
Does the Open Source Medicine Foundation run these trials?
No. OSMF does not sponsor, run or recruit for any trial on this page. We compile public registry entries from ClinicalTrials.gov so patients and clinicians can find them in one place. For questions about a specific study, contact the sponsor or study team listed on its ClinicalTrials.gov record.
We summarise newly registered post-viral trials and notable results on the OSMF Substack.
Subscribe on SubstackOpen Source Medicine Foundation. Ritonavir clinical trials for Long COVID, ME/CFS and post-viral illness (3 trials, updated October 2026). Research Tracker, 07 October 2026.
https://research.opensourcemed.info/trials/by-agent/ritonavir.htmlUnderlying dataset (JSON, CC BY 4.0):
https://research.opensourcemed.info/data/clinical_trials/clinical_trials_current.json. Source records: ClinicalTrials.gov.Related: all agents · recruiting Long COVID trials · recruiting ME/CFS trials · open in trial finder.