Viral rebound and clinical outcomes in hospitalized patients with COVID-19

Viral rebound has emerged as a virologic characteristic. The study aimed to explore its determinants and impact on clinical outcomes.

The study included adults hospitalized for COVID-19 at a tertiary hospital in Taiwan from January to December 2022. Viral rebound was defined as a ≥ 5-unit decrease in RT-PCR Ct values or a new positive antigen test after tested negative within 10-30 days of diagnosis. The primary outcome was viral rebound, and secondary outcomes included 30-day mortality and in-hospital overall mortality.

Among 353 patients, 46 (13%) developed viral rebound. Patients with viral rebound exhibited longer hospitalization [25 days (IQR: 16-37) vs. 17 days (IQR: 12-28), p=0.013], higher 30-day mortality (21.7% vs. 9.8%, p=0.017) and overall mortality (28.3% vs. 16.3%, p=0.048). Systemic dexamethasone use for initial COVID-19 was independently associated with increased risk of viral rebound (adjusted odds ratio [aOR], 1.99; 95% CI, 1.06-3.75, p=0.034). In the landmark restricted to those who were alive at day 10 after diagnosis, viral rebound (aOR, 2.56; 95% CI, 1.11-5.88, p=0.027) was an independent predictor of 30-day mortality.

Viral rebound was associated with prolonged hospitalization and increased 30-day mortality, underscoring the need for enhanced clinical monitoring.