Viral RNA shedding duration and patient prognosis and progression to critical illness
The mortality of patients with a long viral RNA shedding duration (≥ 26 days) was significantly lower than patients with a short viral RNA shedding duration (<26 days). The overall mortality of patients with a long viral RNA shedding duration was 9.5%, nearly half that of the 18.6% overall mortality in patients with a short viral RNA shedding duration (P= 0.04). In patients with a long viral RNA shedding duration as compared to a short viral RNA shedding duration, the percentage of patients who progressed to critical illness was smaller, although this difference was not significant (16.7% vs.21.2%, P= 0.37).
By multivariate-adjusted logistic regression model analysis, the factors that were associated with increased mortality risk in patients during the 28 days of observation included increased patient age (OR 1.07, 95% CI: 1.02-1.10), decreased viral RNA shedding duration (OR 0.94, 95% CI: 0.88-0.99), increased SOFA score (OR 2.11, 95% CI: 1.56-2.85) and decreased lymphocyte count (OR 0.28, 95% CI: 0.09-0.91) (Table 2).
Kaplan-Meier analysis indicated that patients with long viral RNA shedding duration (≥ 26 days) as compared to patients with short RNA shedding duration (<26 days) had a significant survival advantage (Figure 2, log-rank P =0.047). Furthermore, the percentage of patients who progressed to critical illness was also significantly reduced in patients with short viral RNA shedding duration (Figure 3, log-rank P =0.029).