A large NIH-funded clinical trial has found that Paxlovid, the antiviral combination commonly used to treat acute COVID-19, did not improve Long COVID symptoms when compared with placebo. The results come from the RECOVER-VITAL Viral Persistence study, which tested whether the drug could help patients whose symptoms may be linked to lingering virus in the body.
What the trial found
The study enrolled 959 adults with Long COVID from 69 sites across the United States and followed them between July 2023 and early 2025. Participants were divided into symptom groups covering cognitive dysfunction, autonomic dysfunction and exercise intolerance, then assigned to one of three treatment groups: 25 days of Paxlovid, 15 days of Paxlovid plus 10 days of ritonavir placebo, or 25 days of ritonavir with placebo for nirmatrelvir.
According to the report, Paxlovid did not appear to improve Long COVID symptoms relative to placebo. The trial did, however, show that the longer treatment course did not cause serious side effects for participants.
Why the findings matter
Researchers said the work adds to the science of studying Long COVID and viral persistence, while also helping to better characterize and measure patient symptoms. The RECOVER initiative continues to run additional clinical trials examining other possible treatments for symptoms reported to affect quality of life.
The findings are important because Long COVID remains a major clinical challenge, and many patients have hoped that antiviral treatment might reduce persistent symptoms. This study suggests that, at least for this approach, the answer is no.
For readers looking to follow the source material, the study was published in The Lancet Infectious Diseases and reported by Mass General Brigham on September 1, 2026. More details about the research can be found in the journal report and the trial summary from the institution. Source report and journal publication.
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