John Taylor, Professor of Economics at Stanford University and developer of the "Taylor Rule" for setting interest rates | Stanford University
John Taylor, Professor of Economics at Stanford University and developer of the "Taylor Rule" for setting interest rates | Stanford University
Stanford Medicine researchers have found that Paxlovid, an antiviral drug combination targeting SARS-CoV-2, does not appear to benefit individuals suffering from long COVID. The findings are detailed in a paper published on June 7 in JAMA Internal Medicine.
In a clinical trial led by Stanford investigators, a 15-day course of Paxlovid was found to be safe but did not reduce symptoms associated with long COVID. Long COVID refers to the persistence or reappearance of COVID-related symptoms three months or more after an initial infection.
“While there are now improved therapies and treatment practices for acute COVID, there’s nothing FDA-approved for long COVID,” said Dr. Linda Geng, clinical associate professor of primary care and population health and one of the trial’s co-principal investigators. “People continue to suffer and the numbers keep piling up.”
The trial enrolled 155 participants who had tested positive for SARS-CoV-2 between November 2022 and September 2023. Most had been vaccinated, and their median age was 43. Participants reported moderate to severe cases of at least two out of six common long-COVID symptoms: fatigue, brain fog, shortness of breath, body aches, and cardiovascular or gastrointestinal issues.
Participants were randomly assigned either a 15-day course of Paxlovid or a placebo along with low dosages of the drugs that constitute Paxlovid—nirmatrelvir and ritonavir. Ritonavir has no direct efficacy against SARS-CoV-2 but enhances nirmatrelvir's concentration in the body.
Despite some anecdotal reports suggesting Paxlovid could alleviate long-COVID symptoms, the study found no statistically significant difference between those taking Paxlovid and those on placebo in terms of symptom severity reduction.
Dr. Upinder Singh, professor and chief of infectious disease at Stanford and co-principal investigator of the trial, noted that while there were no safety concerns with extended use of Paxlovid, it did not provide clear benefits for long-COVID sufferers.
“There are too many questions remaining unanswered,” Singh said. “Should we have tested patients with symptoms present after only seven or eight months instead of 16 or 17? Should we have treated them for a longer time?”
The study suggests that while Paxlovid is safe for extended use, its effectiveness against long COVID remains uncertain. Researchers hope further analyses will provide insights into whether certain subgroups may benefit more from such treatments.
The trial was funded by Pfizer Inc., with contributions from Kaiser Permanente North California researchers.
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