Virologic rebound observed in 20% of patients treated with nirmatrelvir-ritonavir

An observational study of patients being treated for acute COVID-19 in a multicenter health care system observed virologic rebound in about 20 percent of patients treated with nirmatrelvir-ritonavir (N-R) versus about 2 percent of those who did not receive treatment. The findings are published in Annals of Internal Medicine. 

N-R is an oral antiviral widely used in the United Sates to reduce the incidence of hospitalization and death among individuals with mild to moderate COVID-19. Soon after its adoption into clinical care, a clinical and virologic rebound phenomenon was reported, but data are conflicting about how common it is. 

Charles Darwin Signature T-shirt – “I think.” Two words that changed science and the world, scribbled tantalizingly in Darwin’s Transmutation Notebooks.

Researchers from Massachusetts General Hospital and Brigham and Women’s Hospital studied 127 patients with acute COVID-19 to compare the frequency of virologic rebound in patients with (n=72) and without (n=55) N-R treatment. The study outcome was viral rebound within 3 weeks of an initial positive test, defined as either a positive SARS-CoV-2 viral culture following a prior negative culture or sustained elevated viral load after a prior decline.

With frequent monitoring by both PCR and viral culture during the acute stages of COVID-19, the data showed that virologic rebound with replication-competent prolonged viral shedding occurred in approximately 1 in 5 individuals taking N-R. Only 1 untreated patient experienced virologic rebound.

People who rebounded shedded live virus for a median of 14 days versus less than 5 dyas in those who did not. A regression model showed a trend towards higher rates of virologic rebound with earlier N-R initiation after the date of diagnosis and with earlier N-R initiation after the onset of symptoms.

The researchers noted that compared with untreated individuals, those taking N-R were older, had received more COVID-19 vaccinations, and were more often immunosuppressed. 

According to the study authors, these findings should be factored into consideration when weighing the benefits and risks of N-R treatment in patients at low risk for severe disease. Still, for patients at moderate to high-risk for severe COVID-19, the clinical benefits associated with N-R use are well established.  


Sign up for the Daily Dose Newsletter and get the morning’s best science news from around the web delivered straight to your inbox? It’s easy like Sunday morning.

Success! You're on the list.

Cooling down the hot takes on Twitch
Twitch. Some see it as a fun online community of gamers and …
Soundwaves harden 3D-printed treatments in deep tissues
Engineers at Duke University and Harvard Medical School have developed a bio-compatible …
Conversations with Cristina Costantini and Darren Foster: On the passion and perseverence featured in “Science Fair: The Series”
Cristina Costantini and Darren Foster, the dynamic directing duo behind the captivating …
Researchers safely integrate fragile 2D materials into devices
Two-dimensional materials, which are only a few atoms thick, can exhibit some …

Leave a Reply