A Stanford University study has found that a 15-day course of Pfizer’s COVID-19 antiviral treatment Paxlovid does not alleviate symptoms of long COVID. Currently, no treatments have been proven effective for long COVID, which involves lingering symptoms months after the initial infection.
Hopes were high among scientists and patients that Pfizer’s two-drug oral treatment would offer relief, based on anecdotal reports. However, the 15-week study involving 155 participants showed no significant benefit over a placebo in reducing symptoms like fatigue, brain fog, shortness of breath, body aches, and gastrointestinal or cardiovascular issues. Participants had, on average, been suffering from long COVID for over 16 months before joining the trial.
“We did not see a measurable difference based on patient-reported outcomes in the six composite symptoms together,” stated Dr. Upinder Singh, a Stanford Medicine Professor, in an interview. “We didn’t see a benefit in individual symptoms either.”
Dr. Singh suggested that further research could explore longer treatment courses or earlier intervention in the course of long COVID. The study did confirm that Paxlovid, typically prescribed as a 5-day course for early infection, is safe for use over 15 days.
Pfizer announced that these results will not affect its other planned studies on Paxlovid as a potential long COVID treatment. Paxlovid remains the most commonly prescribed at-home COVID-19 treatment in the U.S., approved for adults at risk of severe complications.
In its original clinical trials, Paxlovid reduced hospitalizations and deaths by around 90% among unvaccinated individuals at high risk for severe disease. However, it showed no significant benefit for those at standard risk, including vaccinated patients.
The long COVID trial was funded by Pfizer, with contributions from researchers at Stanford, Kaiser Permanente Northern California, and Pfizer itself.
