A new study from the University of California, San Francisco (UCSF) suggests that an extended course of Paxlovid may benefit some people suffering from long-term COVID. While previous studies suggested that Paxlovid, an antiviral medicine, could not alleviate long-term COVID symptoms, this new case series provides a different perspective. The findings provide cautious hope for patients who are still dealing with persistent health concerns months or even years after recovering from the initial COVID-19 infection. 

According to the Centres for Disease Control and Prevention (CDC), an estimated 17.6 million Americans suffer from long COVID, which refers to persistent symptoms following the acute phase of a COVID-19 infection. Symptoms may include brain fog, weariness, headaches, shortness of breath, chest pain, and even cardiac difficulties. Despite the enormous number of persons affected, there are currently no federally recognised treatments for extended COVID. 

"We're five years into the pandemic, and there's still no clear treatment for long COVID," said Alison Cohen, PhD, MPH, assistant professor at UCSF and study's primary author. "Paxlovid may not be a cure-all, but it could offer real relief to many people." 

Meanwhile, The Institute for Health Metrics and Evaluation estimated in 2024 that the cumulative global incidence of long COVID stood around 400 million individuals at the time, which was estimated to have an annual economic impact of approximately $1 trillion—equivalent to about 1% of the global economy.

The study, published on January 6 in Communications Medicine, a Nature publication, focusses on the experiences of long-term COVID patients who took Paxlovid for various periods of time. Unlike prior studies, which focused on a typical five-day course of the medicine, this case series investigated whether prolonged treatments could help alleviate symptoms. 

The UCSF researchers collaborated closely with patients, many of whom were members of the Patient-Led Research Collaborative, a group of persons who have had long-term COVID and are also researchers. The study focused on 13 patients with long-term COVID who had tried Paxlovid for varying periods. Some patients took the medicine for 15 days, while others received treatment for varying lengths of time depending on their symptoms. 

Five of the 13 patients investigated saw long-term improvement in their symptoms, while several others reported just brief alleviation. Several patients found no effect at all. This heterogeneity highlights the complexities of long-term COVID and the necessity for personalised treatment options. 

One remarkable example included a 56-year-old man who had suffered from chronic COVID since the pandemic began. He suffered from acute weariness, mental fog, and joint discomfort for more than two years. He originally took Paxlovid for five days but saw no results. Three months later, he attempted a 15-day course and saw a considerable improvement in both his mental and physical health. 

In contrast, a 45-year-old woman who contracted protracted COVID in early 2022 had mixed results. After months of debilitating symptoms like respiratory problems and migraines, she took Paxlovid for five days and felt better for three days. She then tried a 15-day course, but it had no effect on her condition. 

One of the most difficult aspects of treating chronic COVID is the variety of symptoms—more than 200 different concerns have been related to the condition. Scientists are still trying to figure out what causes prolonged COVID and why some people recover while others suffer for much longer. UCSF has even established the world's first extended COVID tissue bank to enable researchers study the disorder in greater depth. 

According to Michael Peluso, MD, co-author of the study and chief investigator of UCSF's long COVID research program, long COVID is significantly more intricate than many people realise. "If there's one thing we've learnt over the last five years, it's that COVID is complex. 

Understanding why some patients respond well to Paxlovid while others don’t is an important step toward discovering successful treatments,” said Peluso. 

The UCSF team emphasises that, while Paxlovid may not be suitable for everyone, it could be a useful choice for some people. More study is required to establish who will benefit the most and how long the treatment should endure. Meanwhile, patients and healthcare professionals should stay educated and consider experimental therapies while waiting for more definitive solutions. 

Millions of people worldwide continue to suffer from long-term COVID, which has an impact not only on their health but also their quality of life. As experts work to solve the complexities of this illness, studies like this provide a glimpse of optimism. However, scientists warn that much more investigation is needed before any single treatment can be widely recommended.