There's been a lot of hope that early antiviral therapy will prevent long COVID
In the long aftermath of a pandemic that has left millions still unwell, researchers at the University of California, San Francisco have surfaced a quiet but consequential question: could an existing antiviral drug offer relief to those trapped in the chronic limbo of long COVID? Three carefully documented cases suggest that Paxlovid, already approved for acute infection, may ease the persistent symptoms that afflict roughly 30 percent of those who contract the virus — a possibility that, if confirmed, would carry profound implications for public health. The evidence is not yet proof, but it is enough to demand a more rigorous answer, and the researchers who hold it are now calling on institutions and industry alike to provide the means to find one.
- Up to 30% of COVID survivors develop long COVID — a debilitating constellation of fatigue, brain fog, and chronic pain that can strip people of their ability to work for months on end.
- Three vaccinated patients in their 40s showed meaningful improvement after taking Paxlovid for long COVID symptoms, though one patient's relief collapsed when the drug was stopped, raising as many questions as it answers.
- UCSF researchers published their findings as a preprint — bypassing peer review to accelerate the conversation — signaling the urgency they feel about a condition that medicine still cannot fully explain or treat.
- The scientific community is clear on what must come next: randomized controlled trials, the gold standard of medical evidence, but those trials require NIH and Pfizer funding that has not yet been committed.
- Pfizer acknowledges the emerging real-world signals but has no long COVID studies underway, leaving a critical gap between a promising observation and the clinical validation that could turn it into a treatment.
Three patients in their 40s, all vaccinated, arrived at a UCSF research clinic still suffering weeks or months after their acute COVID infections had resolved. Fatigue, brain fog, a racing heart, chronic pain — the hallmarks of long COVID, a condition that lingers in roughly 30 percent of people who catch the virus and can cost them their jobs and their health for months at a stretch.
What distinguished their cases was what happened when two of them took Paxlovid, Pfizer's oral antiviral. Both reported substantial improvement in their long COVID symptoms. A third patient had taken the drug during his initial infection; his symptoms improved at first, then rebounded after he stopped, and he went on to develop long COVID regardless.
Dr. Michael Peluso and his team published these three case studies as a preprint this week — ahead of peer review — and the implications moved quickly through the research community. The cases are not proof; they are three data points. But they are enough to sharpen an urgent question: does Paxlovid work for long COVID, and under what conditions? If an existing antiviral could address a condition that strikes across age, vaccination status, and initial infection severity, the public health stakes would be enormous.
Peluso and his colleague Dr. Steven Deeks were direct about what must follow. Case reports, they argued, have done their work. What is needed now are randomized controlled trials — and those require funding from the NIH and from Pfizer itself. The UCSF team expressed readiness to conduct such a study; what they lack is resources.
Pfizer's response was cautious. The company has no long COVID studies currently underway but said it is watching real-world evidence as it accumulates. The door remains open, without a commitment behind it. For now, the signal exists. Whether it becomes a treatment depends on whether the institutions with the power to act choose to do so.
Three patients in their 40s, all vaccinated against COVID-19, walked into a UCSF research clinic with a problem that medicine still doesn't fully understand. They had recovered from acute coronavirus infection weeks or months earlier, but their bodies had not. Fatigue that wouldn't lift. Brain fog that made concentration impossible. A racing heartbeat at rest. Chronic pain. Shortness of breath. These are the hallmarks of long COVID, a condition that lingers in roughly 30 percent of people who catch the virus, regardless of whether their initial infection was mild or severe. It can last for months. It can cost people their jobs.
What made these three cases noteworthy was what happened next. Two of them gained access to Paxlovid, Pfizer's oral antiviral pill, and took it. Both reported substantial improvement in their long COVID symptoms. The third patient had already taken Paxlovid during his acute infection, as prescribed. His symptoms improved initially, then rebounded shortly after he stopped the drug. He later developed long COVID anyway.
Dr. Michael Peluso and his team at the University of California, San Francisco published these three case studies this week in a preprint—ahead of formal peer review—and the implications rippled through the research community. Here was anecdotal evidence, carefully documented, suggesting that an existing drug might help a condition that has left researchers scrambling for answers. "There's been a lot of hope that early antiviral therapy, in addition to preventing severe COVID, will prevent long COVID," Peluso said. "And that might be true, but this case suggests that it won't be true 100% of the time."
The cases themselves are not proof. They are three data points, not a clinical trial. But they are enough to sharpen a question that researchers have been asking with increasing urgency: Does Paxlovid work for long COVID, and if so, under what circumstances? The answer matters enormously. Long COVID affects people across the spectrum of initial infection severity. It strikes the vaccinated and the unvaccinated. It strikes children. It is severe enough to keep people from working. If an existing antiviral could address it, the public health implications would be substantial.
Peluso and his colleagues, including Dr. Steven Deeks, made their position clear: the time for case reports has passed. "It provides evidence that we really need to study this soon, and systematically, which means randomized trials," Peluso said. A randomized controlled trial—the gold standard of medical evidence—would require funding from agencies like the National Institutes of Health and from Pfizer itself. The UCSF team expressed willingness to conduct such a study. They lack only the resources.
Pfizer's response was measured. A company spokesman, Kit Longley, stated that the drugmaker currently has no long COVID studies underway. The company is monitoring data from its ongoing clinical studies and watching real-world evidence as it accumulates. The door to further exploration remains open, he suggested, but no commitment has been made.
The three patients in the UCSF report were enrolled in a larger long COVID research trial called LIINC. Their cases emerged from that work, documented and preserved. They represent a small but concrete signal in a field still clouded by uncertainty. Whether that signal becomes a treatment pathway depends on whether the research community can secure the funding and institutional support to test it properly. For now, the call has been made. The evidence, researchers say, is sufficient to justify the next step.
Notable Quotes
There's been a lot of hope that early antiviral therapy will prevent long COVID. And that might be true, but this case suggests that it won't be true 100% of the time.— Dr. Michael Peluso, UCSF
It provides evidence that we really need to study this soon, and systematically, which means randomized trials.— Dr. Michael Peluso, UCSF
The Hearth Conversation Another angle on the story
Why does it matter that these three patients improved on Paxlovid if we don't have a controlled trial yet?
Because long COVID is still largely a mystery. We don't know what causes it, we don't have approved treatments, and millions of people are suffering. Three documented cases showing improvement is a signal worth investigating seriously.
But couldn't they have improved anyway, without the drug?
Absolutely. That's exactly why you need a randomized trial. But the point is that these cases give researchers enough reason to believe the signal is real enough to test it properly.
What about the patient whose symptoms came back after he stopped taking Paxlovid?
That's actually important information. It suggests that if Paxlovid does help long COVID, it might not be a cure—it might be something you need to take for a certain period, or it might only work if you take it at the right time.
So Pfizer isn't interested in studying this?
They're not saying no. They're saying they're watching the data and might explore it further. But they're not funding a trial yet. That would require NIH money, probably, and institutional commitment.
How many people are we talking about?
Roughly 30 percent of everyone who's been infected with COVID develops long COVID. That's tens of millions of people globally. Even if Paxlovid only helps some of them, the scale is enormous.