An antiviral drug used to treat high-risk COVID-19 patients could also benefit patients with long COVID, researchers say.
Summary As the SARS-CoV-2 pandemic continues to evolve, efforts are underway to understand variability in COVID-19 recovery, as well as the impact of factors including viral variants, vaccine status, and COVID treatment -19 in the development and persistence of long COVID symptoms have intensified. We present three cases that demonstrate that variability in the timing of nirmatrelvir therapy may be associated with different outcomes and underscore the need for a systematic study of antiviral therapy for this disease. |
Paxlovid has emergency use authorization from the U.S. Food and Drug Administration to treat COVID-19 patients over age 65 or with underlying health conditions, such as obesity, diabetes or cancer. The pill includes the antivirals nirmatrelvir and ritonavir.
Treatment with Paxlovid must begin within five days of the onset of symptoms and continue for five days, according to the conditions of the authorization.
Now, a series of case reports from researchers at the University of California, San Francisco (UCSF) show some success with Paxlovid in treating patients with long COVID. A third of people infected with the coronavirus are thought to develop symptoms such as fatigue, headaches and brain fog associated with long COVID.
It is believed that long COVID may be caused by the immune system’s continued reaction to the virus that remains in the body after the initial phase of infection.
"Data from other studies show that SARS-CoV-2 could persist for months," said study co-author Dr. Michael Peluso. He is an assistant professor of medicine and an infectious disease specialist at UCSF and Zuckerberg San Francisco General Hospital.
"A recent study shows persistent shedding of the virus from the gastrointestinal tract for up to seven months in some people. This does not mean the virus is infectious, but there may be fragments of the virus, or viral activity, that could be stimulating the immune system," he said. Peluso in a university press release.
The case reports included three patients in their 40s who had symptoms consistent with long COVID.
Two began taking Paxlovid weeks after the onset of long COVID symptoms, against the conditions of the emergency authorization. One was prescribed the antiviral after being re-exposed to the virus more than seven weeks after the onset of symptoms, and his health improved to near normal, according to the researchers.
The other patient took Paxlovid about three weeks after symptoms appeared. She felt less fatigued the day after completing therapy, but she still had shortness of breath and muscle pain.
"It appears that Paxlovid may benefit long COVID patients, but there is no way to access the drug unless a doctor is willing to bend the rules, which we do not advocate," Peluso said.
The third patient began taking Paxlovid within 24 hours of the onset of COVID-19 symptoms, according to emergency use conditions. His symptoms improved, but they returned four days after completing Paxlovid therapy, with fever, runny nose, cough, and chest pain. He also had an elevated temperature and heart and breathing rates.
About two weeks later, he developed brain fog, chest pain, fatigue, and malaise after exertion, symptoms consistent with long COVID.
"The key aspect of this case is that longer courses of Paxlovid may be needed, and giving it too early may not be optimal," Peluso said. He noted that there is no safety data yet to support long-term use of the drug.
The case series was published online on the Research Square preprint server . It has not been peer-reviewed or published in a journal, so the findings should be considered preliminary. The results should be confirmed with future rigorous studies, the authors emphasized.
"Only by doing rigorous studies will we get answers," Peluso said. "There is a critical need for this, given the large number of people who have had COVID, a significant subset of whom have had COVID for a long time."
