Can Paxlovid treat long Covid? A new report suggests it may help some patients, but which patients might benefit is unclear.
The report, published Monday in the journal Communications Medicine, describes the cases of 13 long-Covid patients who took extended courses of the antiviral drug. The results were decidedly mixed: Nine patients reported some improvement, but only five said it lasted. Four reported no improvement.
Perhaps more than anything, the report highlights that, nearly five years into the pandemic, little is known about what can help millions of people with long-term Covid. Although some people improve on their own or with various therapies and medications, no treatment has yet proven to be widely successful.
“People with long-Covid are eager for treatments that can help,” said Alison Cohen, an epidemiologist at the University of California, San Francisco, author of the new report and herself a long-Covid sufferer. “There has been a lot of research, but it continues to go slowly.”
Paxlovid, made by Pfizer, is seen as an attractive prospect because it can prevent severe disease during active Covid infections and because patients who take the five-day course during the infection are less likely to develop long-term Covid afterwards.
Additionally, a theory that some cases of long-lasting Covid could be caused by remnants of the virus in the body suggests that an antiviral like Paxlovid could eliminate those symptoms by extinguishing the lingering virus.
Last year, the first randomized trial of Paxlovid for long-term Covid showed no benefit. Conducted at Stanford, it involved 155 patients who took the drug or a placebo for 15 days. While taking Paxlovid for that long was found to be safe, it didn’t help patients much: Ten weeks later, the placebo and Paxlovid groups showed no significant difference in the severity of long-term Covid symptoms.
Dr. Upinder Singh, an infectious disease specialist and leader of that study, said his findings and the new report mostly generated “more questions to answer”: Could Paxlovid help if taken for more than 15 days or combined with other drugs? Does its effect vary based on the type of symptoms or when they started?
“It’s very likely that in the long run of Covid there will be different types of illnesses,” said Dr. Singh, now head of the department of internal medicine at the University of Iowa. Perhaps Paxlovid or other antivirals could help patients who may be clearly convinced they have a persistent virus in their bodies, he said.
Akiko Iwasaki, an immunologist at Yale University, said scientists should not “throw in the towel” on the possibility of antivirals being used for Covid for a long time.
“If you look at it overall, you don’t see a difference between the placebo group, but these clinical cases show that there are people who really benefit from it, so we need to focus on those people,” said Dr. Iwasaki, who is leading a another randomized trial of Paxlovid, the results of which have yet to be published.
He said important next steps would be to identify biological markers in people whose long-term Covid symptoms improved with Paxlovid and see whether other antivirals help different patients.
The new report was not a clinical study, but a compilation of self-reports from 13 long-Covid patients across the country who had tried extended courses of Paxlovid. This is the first published case series of such patients, according to the authors, who include Dr. Michael Peluso, an infectious disease doctor at UCSF, and members of the Patient-Led Research Collaborative, a group of researchers who also have Covid for a long time.
The patients’ experiences were too varied to produce a coherent trajectory, but the variety may provide clues for larger studies, the authors said.
The patients, aged 25 to 55, were infected between March 2020 and December 2022. They experienced one or more different symptoms, including fatigue; gastrointestinal problems; cognitive problems such as brain fog; muscle pain; irregular heart rate; and a condition called post-exertional malaise, in which physical or mental exertion causes setbacks.
As was the case in the Stanford study, most of the patients in the new report had been vaccinated at the time they took Paxlovid. Their Paxlovid courses ranged from 7.5 days to 30 days. Most tried it to find relief from lingering Covid symptoms; two long Covid patients received extended courses of Paxlovid when they were reinfected with the virus.
Most patients were also taking other medications or supplements, making it difficult to determine the specific effect of the drug, Dr. Cohen said. However, some have said that Paxlovid has helped them significantly.
Kate Leslie, 46, a social worker in Boulder, Colorado, said she was healthy and athletic before becoming infected with the coronavirus in March 2022. Six weeks later, she said, she felt as if she had had a concussion, struggling to think clearly and find the words.
He developed postural orthostatic tachycardia syndrome, with symptoms including irregular heart rate and blood pressure and occasional fainting. A longtime Ultimate Frisbee player and coach, she began to feel profound fatigue and could barely lift her arms.
“It was like concrete blocks were on your body,” he said. “I couldn’t get out of bed. My husband had to wash my hair, dry it and dress me.”
After an antiviral she was prescribed for a flu infection, Tamiflu, ended up relieving some of her long Covid symptoms, Ms Leslie wondered whether Covid-related antivirals might help even more, she said . In February 2023, she found a doctor who prescribed a 15-day course of Paxlovid.
Afterward, “I could feel my body recovering,” he said, adding, “I started to get my energy back.”
About six months later, she took another 15-day course, which helped her again, she said. He estimates it can now function at about 85% of its pre-Covid level.
Ms. Leslie said, however, that a couple of her medical problems worsened after Paxlovid, including an immune system condition that caused allergies. Three other patients also reported bothersome problems after taking Paxlovid, including tingling and gastrointestinal discomfort.
Among those who perceived no benefit from the drug was Julia Moore Vogel. Dr. Vogel, 39, a senior program director at Scripps Research, was a marathon runner before she was infected with the coronavirus in July 2020. She now uses a wheelchair and is largely homebound, she said.
She and her daughter recently moved across the country from California to live with her parents in Schaghticoke, New York. “It got to the point where we were like, either I have to stop working or we need more help at home,” she said.
Dr. Vogel, whose symptoms include fatigue, post-exertional malaise and migraines, took a 10-day course of Paxlovid in April 2023. “It had no impact for me,” she said.
These days he manages his energy carefully, trying to leave the house no more than once a week. Migraine medications have provided some relief, he said, but other than that, “I’ve tried a lot of things, and basically nothing has really helped me get better.”
Dr Cohen said the report strengthens the theory that long Covid has many different causes and treatments.
“A really important question is who might benefit from taking an extended course of Paxlovid and why,” he said, “and if it benefits some symptoms, which symptoms does it benefit?”