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“Paxlovid Rebound” Is Just COVID Rebound

1 December 2022 by Gertrud U. Rey

by Gertrud U. Rey

Image Credit: Dreamstime

The antiviral drug Paxlovid is highly effective at inhibiting SARS-CoV-2 replication and reducing symptoms associated with COVID-19. Nevertheless, there have recently been numerous reports of recurrence of positive tests and symptoms after completing treatment with Paxlovid, leading some to infer that the drug triggers the recurrence. Is this inference actually correct, or would the recurrences happen regardless of treatment? In other words, is “Paxlovid rebound” really just COVID rebound?

Most studies aiming to address this question have been retrospective analyses, which use existing data collected from events that have already happened. A major disadvantage of examining data retrospectively is that it is impossible to randomly assign participants to experimental or control groups, or to even apply the proper controls as is typically done in a prospective study. These drawbacks often lead to a biased selection of participants such that they do not always represent the population that is intended to be analyzed, which leads to inaccurate results and false conclusions.

In an attempt to remedy this shortcoming, a group of investigators led by Michael Mina carried out a prospective study in which they compared the outcomes between two groups of COVID-19 patients: a group of 127 subjects who chose to be treated with Paxlovid and a control group of 43 subjects who chose not to be treated. The aim of the study was to determine whether Paxlovid recipients experience a higher incidence of rebounds than non-treated individuals.

To qualify for the study, all participants had to test positive for SARS-CoV-2 using a rapid antigen test. The day of the first test was then documented as day 0 and the participants continued testing themselves and recording their symptoms on days 2, 5, 7, 9, 11, 13, 15, and 17 of the study period. Any positive antigen test after a negative test within the 17-day period was defined as a viral rebound, and any recurrence of symptoms after initial symptom clearance within the same period was defined as a symptom rebound. At the 17-day time point, among the Paxlovid group, 14% of subjects had experienced a viral rebound and 19% had experienced a symptom rebound. In contrast, only 9% of subjects in the (untreated) control group had a viral rebound and only 7% had a symptom rebound. There were no noteworthy differences in the number of rebounds between the two groups at the one-month time point. Although the incidence of rebound was slightly higher in the Paxlovid group, this difference between the two groups was not statistically significant; it was likely due to random chance and the small sample sizes of the groups. In other words, the slightly higher incidence of viral and symptom rebounds in the Paxlovid group has no clinical meaning, and one can interpret the rate of rebounds between the Paxlovid and control groups to be similar, meaning that Paxlovid probably does not cause viral and/or symptom rebounds.

The authors thoughtfully note that the study has several limitations. First, the overall sample size of 170 participants is small and there was a large difference between the sizes of the two groups (i.e., 127 subjects in the Paxlovid group and 43 subjects in the control group). Large and balanced sample sizes are critical for reducing the margin of error and for obtaining results that are both accurate and clinically useful. Second, the participants tested themselves, which could have introduced unknown errors such as whether the tests were carried out properly or at the correct time. Third, participants were asked to only test every other day to ensure compliance; however, daily testing would have provided additional data points and more comprehensive findings. Larger surveys done under more controlled and standardized conditions are needed to validate the results obtained in this study.

In contrast to popular opinion, rebounds can happen after most viral infections, so there is nothing unique about SARS-CoV-2 in this regard. Even if Paxlovid does cause viral and/or symptom recurrence in a small subset of people, a preponderance of the evidence indicates that early treatment with Paxlovid results in an overwhelming reduction in hospitalization and death for COVID-19 patients. Understanding the underlying mechanisms leading to rebounds can help guide practitioners to modify timing and length of treatment with Paxlovid or other antiviral drugs to reduce the incidence of rebound.

Filed Under: Basic virology, Gertrud Rey Tagged With: antiviral, antiviral drug, COVID rebound, COVID-19, Michael Mina, Paxlovid, Paxlovid rebound, prospective study, rapid antigen test, rebound, retrospective study, SARS-CoV-2, symptom rebound, viral rebound

Trial By Error: The Long COVID Survival Guide and the Role of Patients in Research

22 November 2022 by David Tuller

By David Tuller, DrPH

“The Long COVID Survival Guide: How to Take Care of Yourself and What Comes Next—Stories and Advice from Twenty Long-Haulers and Experts” is pretty much what it sounds like. The anthology was published earlier this month, and each chapter is written by one or more contributors. The topics covered address long Covid through a variety of lenses–the biases of the health care system, financial impacts, the importance of pacing, the challenge of cognitive impairments, menstruation, disability rights, and so on.

I spoke earlier today with three of those involved in the book. Writer Fiona Lowenstein, the book’s editor, brought public attention to the issue of prolonged recovery early in the pandemic through a prescient opinion piece in The New York Times in April, 2020. Lowenstein is a founder of Body Politic, the wellness collective that generated early survey data about persistent symptoms after acute bouts of Covid-19. Our conversation also included two contributors to The Long COVID Survival Guide. Lisa McCorkell works with the Patient-Led Research Collaborative, which arose out of Body Politic’s efforts, and wrote about how to parse medical research; Padma Priya, an Indian journalist, wrote about the importance of peer-to-peer and community support, especially in countries with fewer medical resources.

Thanks to all three of them! I have posted the conversation on YouTube and below.

Filed Under: David Tuller, ME/CFS Tagged With: fiona lowenstein, Long Covid

TWiV 954: Speculating sarbecovirus spillovers with Michael Letko

13 November 2022 by Vincent Racaniello

Michael Letko joins TWiV to discuss his research on understanding cell receptors required for sarbecovirus entry, including an ACE2-dependent isolate from Russian bats that is resistant to vaccine-induced antibodies.

Hosts: Vincent Racaniello, Dickson Despommier, Rich Condit,  Kathy Spindler, and Brianne Barker

Guest: Michael Letko

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Show notes at microbe.tv/twiv

Filed Under: This Week in Virology Tagged With: ACE2, cell entry, coronavirus, COVID-19, Khosta virus, pandemic, RBD, sarbecovirus, SARS-CoV-2, Tmprss2, trypsin, viral, virology, virus, viruses

Trial By Error: More on that New York Magazine Piece Pushing Psychogenic View of ME/CFS and Long Covid

12 November 2022 by David Tuller

By David Tuller, DrPH

So getting back to that long, ill-informed and poorly reported New York Magazine article on the purportedly psychogenic nature of both long Covid and ME/CFS…I responded in a twitter thread to the article’s misrepresentations of my criticisms about the PACE trial.

The journalist, a science writer named Jeff Wise, didn’t interview me. But he did interview three other critics of the CBT/GET paradigm—Columbia physician-scientist Mady Hornig; Lucinda Bateman, a physician who specializes in ME/CFS and related diseases; and Solve ME/CFS Initiative’s director of advocacy, Emily Taylor. All felt their words and positions were misrepresented and have voiced their objections in a public statement.

[Read more…] about Trial By Error: More on that New York Magazine Piece Pushing Psychogenic View of ME/CFS and Long Covid

Filed Under: David Tuller, ME/CFS Tagged With: feff wise, new york magazine, PEM, tufecki

TWiV 953: Clinical update with Dr. Daniel Griffin

12 November 2022 by Vincent Racaniello

In his weekly clinical update Dr. Griffin discusses high demand for Amoxicillin causing shortages amid child RSV surge, epidemiologic and clinical features of children and adolescents aged <18 years with monkeypox, low risk of SARS-Cov-2 transmission by fomites, nucleocapsid antigenemia is a marker of acute SARS-CoV-2 infection, impact of community masking on COVID-19,  protection against Omicron from vaccination and previous infection in a prison system, Nirmatrelvir and the risk of post-acute sequelae of COVID-19, Bebtelovimab for high-risk outpatients with early COVID-19 in a large US health system, imprinted SARS-CoV-2 humoral immunity induces convergent Omicron RBD evolution, can SARS-CoV-2 trigger new onset of autoimmune disease in adults? A case-based review, and retrospectively modeling the effects of increased global vaccine sharing on the COVID-19 pandemic.

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Show notes at microbe.tv/twiv

Filed Under: This Week in Virology Tagged With: antiviral, coronavirus, COVID-19, delta, inflammation, Long Covid, marburg virus, monkeypox, monoclonal antibody, Omicron, pandemic, poliovirus, SARS-CoV-2, vaccine, vaccine booster, variant of concern, viral, virology, virus, viruses

Trial By Error: Recent News Articles Highlight Post-Exertional Malaise

11 November 2022 by David Tuller

By David Tuller, DrPH

A few prominent news articles have recently drawn welcome attention to the links and overlaps between ME/CFS and long Covid. One key overlap is the core ME/CFS symptom generally known as “post-exertional malaise” (PEM). This term is so embedded in conversations in the ME and ME/CFS worlds that it is easy to forget others outside that bubble have no idea what it is or what it means or how devastating the experience is for patients.

[Read more…] about Trial By Error: Recent News Articles Highlight Post-Exertional Malaise

Filed Under: David Tuller, ME/CFS Tagged With: PEM, PESE, tufecki

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