A SONAR report on Nirmatrelvir/ritonavir-associated rebound COVID-19: Using new databases for evaluating new diseases

In May 2022, the Centers for Disease Control and Prevention disseminated an alert advising that "a few" persons with Nirmatrelvir/ritonavir (NM/R)-associated rebound of COVID-19 infection had been identified. Three case reports appearing as pre-print postings described the first cases. Analyses in March 2023 by NM/R's manufacturer and the Food and Drug Administration (FDA) reported no association between NM/R and COVID-19 rebound in a large phase 3 randomized clinical trial. Our study evaluated if social media databases or electronically disseminated new articles might provide insights related to the putative new toxicity, NM/R-associated COVID-19 rebound.

Information on NM/R-associated COVID-19 rebound cases was abstracted from preprint postings of non-peer-reviewed manuscripts, social media websites, electronically disseminated print and television media reports, a new FDA adverse event database for drugs that received Emergency Use Approval, and news articles in scientific journals.

Thirty-five persons experienced presumed or documented NM/R-associated COVID-19 rebound, based on information described in preprint services (n = 27), Twitter postings and related news articles (n = 7), and news articles without related Twitter reports (n = 1). These reports included information on dates of initial COVID-19 illness and rebound onset, COVID-19 testing, vaccine status, presentation, and outcome. A new FDA safety database identified 12,500 possible cases of this toxicity, but the quality of these data was poor. Preprint postings preceded peer-reviewed publications describing the same cases by four months. Social media websites including Instagram, Reddit, YouTube, the Center for Disease Control and Prevention's (CDC) Health Alert Network, CDC Twitter, and Facebook did not provide clinically meaningful information on individual cases.

Preprint services and Twitter facilitated identification of the largest case series of NM/R-associated COVID-19 rebound. The cases were reported in non-peer-reviewed media several weeks prior to the first peer-reviewed electronically disseminated publication of one person with this diagnosis.