Paxlovid: Covid-19 infections rebounding a few days after treatment *4 UPDATES*

Coronavirus, Health, Healthcare, Immunocompromised, Infection, Paxlovid, Recurrence, Reinfection, Side Effects, Symptoms, Treatment

There are some anecdotal reports on social media today about Covid-19 infections rebounding a few days after taking Paxlovid. The rebound effects could be caused by reinfection, the biphasic effect of the virus, Paxlovid not clearing the infection completely, or by another unknown mechanism.  If you are taking Paxlovid, then you should probably read up on this.











UPDATE 1 – 21st April 2022

Twitter and Reddit have been filled with patients and doctors sharing their experiences and hypotheses over the past few days, including John Donoghue, a 71-year-old emeritus physics professor in Amherst. “We had three cases in the house with the same pattern,” Donoghue said, in an interview.

Donoghue, his wife, and her 95-year-old mother all were infected with COVID in the last month. All three received Paxlovid, felt better, and tested negative on rapid tests for four or five days. Then their symptoms returned and each one tested positive again.

Boston Globe article: Patients report a rebound of COVID-19 symptoms after taking the antiviral Paxlovid

UPDATE 2 – 28th April 2022

“Our findings suggest that viral replication and COVID-19 symptoms may recur after very early treatment with NM/R before natural immunity is sufficient to fully clear SARS-CoV-2.”

Preprint: Rapid Relapse of Symptomatic SARS-CoV-2 Infection Following Early Suppression with Nirmatrelvir/Ritonavir

UPDATE 3 – 30th April 2022

U.S. government researchers are planning studies of how often and why coronavirus levels rebound in some Covid patients who have completed a five-day course of treatment with Pfizer Inc.’s Paxlovid.

Bloomberg report

UPDATE 4 – 15th May 2022

Preprint: “We describe relapse of COVID-19 symptoms and SARS-CoV-2 viral load following nirmatrelvir/ritonavir (NM/R) in 8 non-immunocompromised patients aged 31 to 71-years-old.

Most patients improved rapidly after treatment with NM/R and had negative antigen or PCR tests prior to relapse on Days 9-12 of their illness. Relapse symptoms were described most frequently as cold symptoms, though some patients experiencing a recurrence of fatigue and headache. All relapses resolved without additional antiviral treatment. Viral load during relapse was comparable to levels during initial infection.

Sequencing in three patients indicated that relapse was not due to a treatment-emergent mutation or infection with a different viral strain. One patient transmitted SARS-CoV-2 to two family members during relapse. The presence of high viral load and the occurrence of one transmission event suggest that patients with relapse should isolate until antigen testing is negative.”

Preprint: Rapid Relapse of Symptomatic Omicron SARS-CoV-2 Infection Following Early Suppression with Nirmatrelvir/Ritonavir


NOTE: The original tweet by Andrew Teman that started this thread has since been made private



Anthony Fauci Paxlovid rebound


Image by Kches16414, CC BY-SA 4.0, via Wikimedia Commons

** This post was originally published on April 19, 2022 **