Symptom and viral rebound rare after untreated COVID-19 infection: Study

A combination of symptom and viral rebound after untreated COVID-19 infection is rare, occurring in only three per cent of study participants, an analysis of a COVID-19 trial has found.

Widespread use of nirmatrelvir -- a recommended treatment for outpatients with mild to moderate COVID-19 -- has been accompanied by reports of worsening symptoms and virologic rebound after treatment completion, the researchers said.

Virologic rebound has also been reported in persons who did not receive nirmatrelvir therapy, they said.

However, studies that can define the frequencies of symptom and viral rebound during the natural course of COVID-19 are lacking.

Researchers from Brigham and Women's Hospital in the US conducted an analysis of 563 participants receiving placebo in a trial.

The study, published in the journal Annals of Internal Medicine, found that a combination of symptom and high-level viral rebound occurred in only three per cent of participants.

Symptom rebound alone occurred i