COVID-19 Research Explores Virologic Rebound Definitions and Viral load Dynamics
A recent study investigating COVID-19 symptomatology and treatment outcomes has examined three distinct definitions of virologic rebound, a phenomenon where viral load increases after a period of suppression. These definitions, drawn from previous research, aim to capture different aspects of viral resurgence following antiviral treatment.
Teh first definition (i) considers virologic rebound as a decrease in the Cycle threshold (Ct) value by at least 3 units within 21 days after the end of oral antiviral treatment. For patients not receiving oral antivirals,treatment completion was proxied by 5 days post the index date,reflecting the median time to completion for those who did receive treatment. This approach aligns with methodologies used in prior clinical trials and observational studies.
The second definition (ii) identifies virologic rebound as at least two consecutive Ct measurements exceeding 30, followed by at least two consecutive measurements below 30.This definition focuses on a clear shift in viral detection levels.
The third definition (iii) characterizes virologic rebound by a reduction in two consecutive Ct values from above 40 to 40 or below. This definition highlights a notable drop in viral load after an initial high viral burden.To further understand the relationship between virologic rebound and viral burden over time, a post-hoc analysis was performed. This analysis utilized mixed-effect models to assess Ct measurements within 40 days of the index date.All statistical analyses were conducted using R software, version 4.2.2.
Further details regarding the research design are available in the Nature Portfolio Reporting Summary accompanying the article.
