Reports recently surfaced that two long COVID sufferers found success with pharmaceutical company Pfizer Inc’s antiviral pill PaxlovidTM. One of the longhaulers was a researcher living with debilitating chronic fatigue who tested the drug on herself. After taking the dual-drug oral therapy, her symptoms disappeared.

Though just single-patient case studies, in light of an imminent public health crisis, experts and advocates believe they justify clinical research. HIV expert Steven Deeks, M.D. of the University of California, San Francisco (UCSF), said that while pharma companies tend to dismiss single case studies, these Paxlovid anecdotes could help drive long COVID research in much the same way such cases have driven HIV research.

Deeks has heard of another person at UCSF whose long COVID symptoms resolved with Paxlovid. To him, these cases provide “really strong evidence that we need to be studying antiviral therapy in this context as soon as possible.”

Still Just a Theory

Scientists are quick to point out that these cases do not prove that Paxlovid was responsible for relief of long COVID symptoms. They do, however, support the popular theory that long COVID may result from lingering virus months after recovery from initial acute infection.

A National Institutes of Health (NIH) study, now under peer review, offers the strongest evidence of this theory to date. In the study, 44 individuals infected with SARS-CoV-2 who had died from either COVID-19 or another cause were autopsied. The bodies revealed that the virus was still widespread, even in the brain. The study showed the virus can linger in the body more than seven months after initial symptoms begin.

Growing Frustration

Paxlovid is a two-pill therapeutic combining Pfizer’s new antiviral nirmatrelvir with its older antiviral ritonavir. The drug is authorized to be taken in the initial days of COVID infection to help avoid severe disease in high-risk individuals.

Despite the pressing need for long COVID therapies, Pfizer says it has no current studies on long COVID and hasn’t indicated whether it plans any in the future. A Reuters investigation revealed that fewer than 20 clinical trials of potential long COVID treatments are now underway, with just a handful beyond the early stages. 

While there are new efforts to boost treatment research, its sluggishness to-date has been a source of growing frustration among long COVID sufferers. Patient advocate and Survivor Corps founder Diana Berrent has been lobbying for federal funding of large long COVID clinical trials. She believes that basing research on anecdotal reports is inadequate. Still, the evidence regarding Paxlovid is encouraging and deserves further investigation.

Success Stories

One of the two anecdotal reports of patients experiencing relief of long COVID symptoms with Paxlovid was documented by Stanford Health Care’s long COVID clinic. It involved a 47-year-old vaccinated woman who was previously healthy and developed COVID-19 during the summer of 2021. Though most of her initial symptoms resolved after a couple of days, she continued to live with severe fatigue, brain fog, post-exertional malaise, and other symptoms. 

After six months, she likely became re-infected with COVID and many of her initial acute symptoms returned. Now prescribed a standard five-day course of Paxlovid, the woman’s long COVID symptoms improved by the third day and she is now “back to normal.”

The second account involved 37-year-old immunologist Lavanya Visvabharathy, Ph.D. of Northwestern Medicine’s long COVID clinic, who came down with COVID-19 in December 2021. Though she had mild early symptoms, she was later beset with chronic fatigue, headaches, and difficulty sleeping for over four months post-infection, all the while testing positive for the virus. Aware of the Stanford case and NIH research, she decided to try Paxlovid for any residual virus. By the end of five days, she had less fatigue, fewer headaches, and better sleep, and after another two weeks, her fatigue was “100% fixed.”

Proof Needed (with a Dose of Caution)

Visvabharathy recognizes that carefully controlled trials are needed to prove her experience with Paxlovid. What’s more, there’s a laundry list of common medications that interact with ritonavir. 

Said Northwestern Medicine’s Dr. Igor Koralnik, who directs their long COVID clinic, Paxlovid “can’t be used willy nilly” and “is not a benign medication.”

Like other experts, he’d like to see studies.

*Steenhuysen, J. (2022, April 18). The case for testing Pfizer’s Paxlovid for treating long COVID. Reuters. https://www.reuters.com/business/healthcare-pharmaceuticals/case-testing-pfizers-paxlovid-treating-long-covid-2022-04-18