(HealthDay News) — For outpatients with mild-to-moderate COVID-19, symptom rebound and viral RNA rebound are relatively common, but the combination of symptom and viral rebound is rare, according to a study published online Feb. 21 in the Annals of Internal Medicine.
Rinki Deo, PhD, from Harvard Medical School in Boston, and colleagues conducted a multicenter trial to characterize symptom and viral rebound in 563 untreated outpatients with mild-to-moderate COVID-19 in a retrospective analysis of a randomized trial. The severity of 13 symptoms was recorded daily between days 0 and 28 for participants receiving placebo in a placebo-controlled trial. On days 0 to 14, 21, and 28, nasal swabs were collected for severe acute respiratory syndrome coronavirus 2 RNA testing.
The researchers found that 26% of patients had symptom rebound at a median of 11 days after initial symptom onset. In 31 and 13% of participants, respectively, viral rebound and high-level viral rebound were detected. Symptom and viral rebound events were mainly transient; 89 and 95% of symptom and viral rebound events, respectively, occurred at a single time point before improving. Only 3% of participants had a combination of symptom and high-level viral rebound.
“These results provide insight into the natural trajectory of viral rebound and symptom relapses during COVID-19, which is critical in the interpretation of studies reporting biphasic disease courses after nirmatrelvir-ritonavir or other antiviral treatment,” the authors write.
