Paxlovid fails to improve long-COVID symptoms in small study – University of Minnesota Twin Cities

Using the popular COVID antiviral Paxlovid failed to significantly improve symptoms in 155 patients experiencing moderate to severe long COVID, according to a study published today in JAMA Internal Medicine.

The findings are part of the STOP-PASC trial, and the study was conducted at Stanford University from November 2022 to September 2023. All enrollees reported at least 3 months of postacute sequelae of SARS-CoV-2 infection (PASC) symptoms.

The participants were randomized at a rate of 2:1 to treatment with oral nirmatrelvir-ritonavir (Paxlovid) or with placebo twice daily for 15 days. Paxlovid is given as a 5-day course of pills during acute COVID-19 infections to prevent disease progression in those at risk of moderate to severe complications from the virus.

Some recent studies have suggested that using the antiviral during the acute phase of infection lowered risk of later developing long COVID. This is the first known study to formally look at Paxlovid as a treatment in patients with established long COVID.

The average age of participants was 42 years, and 153 of 155 reported having the primary COVID-19 vaccine series. The mean time between index SARS-CoV-2 infection and randomization was 17.5 months. Of the long-COVID patients, 102 received Paxlovid.

At 10 weeks post-intervention, participants were assessed on six main areas of long-COVID symptoms: fatigue, brain fog, shortness of breath, body aches, gastrointestinal symptoms, and cardiovascular symptoms. Participants were asked to rate the severity of each symptom in the past 7 days.

Although a 15-day course of Paxlovid was found to be safe, it didn't demonstrate a significant benefit in improving symptoms.

"Considering the 6 core symptoms together (fatigue, brain fog, body aches, cardiovascular symptoms, shortness of breath, gastrointestinal symptoms), there was no statistically significant difference in the pooled symptom severity," the authors said.

There was no statistically significant difference in the pooled symptom severity

Measurements of secondary outcomes, including a 1-minute sit-to-stand test and orthostatic vital signs, also showed no significant differences between the groups from baseline to 10 weeks.

"With the urgent need to find therapies for PASC, exploratory studies such as ours have pushed forward to simultaneously assess efficacy and safety while investigating biomarkers. We underscore the need to establish validated clinical and biological end points for PASC," the authors concluded.

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Paxlovid fails to improve long-COVID symptoms in small study - University of Minnesota Twin Cities