Stanford researchers launch first study on long-COVID treatment with Pfizer's Paxlovid

Researchers at Stanford University are launching a new study to see whether Pfizer's anti-viral drug Paxlovid, which is approved to treat COVID-19, might also be an effective cure for so-called "long COVID" that causes suffering in patients long after their initial SARS-CoV2 infection.

More than 98 million Americans have had COVID-19 since the pandemic began, according to data from the Centers for Disease Control and Prevention.

The CDC estimates as many as 1 in 5 adults who have had COVID-19 later experience long COVID symptoms.

"Fatigue, cognitive issues, shortness of breath, the list really goes on," said Dr. Linda Geng, who is Co-Director of Stanford's Post-COVID clinic.

Dr. Geng says the study is the first in the nation to test Paxlovid on people with long COVID symptoms.

"One of the leading ideas or hypotheses about what could be going on in some individuals is potentially this idea of a lingering viral reservoir, meaning that there are some parts of the body perhaps that are still harboring the virus," said Dr. Geng, "There is some scientific evidence to show that in some individuals, there are pieces of the virus that can be found even months after the initial infection."

Dr. Geng says they are looking for people who've had post-COVID symptoms for more than three months.

"Our study aims to enroll about 200 participants and follow them over a 4.5-month period of time," said Dr. Geng.

"Right now, we don't have known biomarkers, meaning we can't do a blood test that says this is long COVID, and now we have treated it so that signal goes away. Right now and perhaps the most important thing is that we go by patients' reports, so their own report of their symptoms, their own call and judgment of the severity of their symptoms, and how much it has impacted their daily lives. So for our study, that's what we will be measuring. It's called patient reported outcomes meaning their own assessment of how they're feeling."

Diana Güthe, is founder of, a grassroots community to help long-COVID survivors and doctors find answers. 

She says she is encouraged that there is attention to long COVID research, which she and others have called for through their advocacy group.

"I had one of the first confirmed cases of COVID in the country in early March 2020," said Güthe. She says after she got better, though, some symptoms didn't go away, "I had what I call a relapsing remitting case of long COVID They came and went for several months and lasted about up to a year. "

"We have probably close to a quarter of a million members," she said, "These are people who cannot get back to their lives. They can't get back to their livelihoods. And there's an urgency to finding help for people."

Güthe is encouraging people to sign up for trials such as the Stanford study and push for more medical research into other options such as blood plasma donations and other drugs.

"We need to be doing it along with a million other trials. We need to be trying other antivirals like remdesivir. We need to be trialing monoclonal antibodies," said Güthe, "And if I had my money, I would put it on Vax-plasma, that's the plasma like a blood donation that you get from an individual who has an antibody, who has antibodies from both a natural infection and from the vaccine."

Dr. Geng says to enroll in the Stanford study, the participant must be an adult able to travel to Stanford for five clinical visits and not have received Paxlovid in the past 30 days.

Jana Katsuyama is a reporter for KTVU.  Email Jana at and follow her on Twitter @JanaKTVU or Facebook @NewsJana or