Viral kinetics and factors associated with rapid viral clearance during lopinavir/ritonavir-based combination therapy in non-severe COVID-19 patients.

OBJECTIVE: Lopinavir/ritonavir has modest antiviral activity against severe acute respiratory syndrome coronavirus 2. The aim was to investigate the viral kinetics and factors associated with viral clearance during lopinavir/ritonavir-based combination treatment in non-severe patients. PATIENTS AND METHODS: Sixty-four patients were retrospectively enrolled. Viral RNA was detected by real-time RT-PCR assay from sputum or throat swab samples at different time points. The patterns of viral kinetics were characterized, and factors associated with rapid viral clearance, which was defined as viral RNA undetectable within two weeks, were analyzed using multivariate logistic regression analyses. RESULTS: All patients achieved viral RNA negativity and were discharged from the hospital. Furthermore, 48 (75%) and 16 (25%) patients achieved rapid and delayed viral clearance, respectively. The lymphocyte counts of rapid viral clearance patients (1.40 [1.20-1.80] x 10(9)/L) were higher, when compared to delayed viral clearance patients (1.00 [0.70-1.47] x 10(9)/L) (p=0.024). The multivariate logistic analysis revealed that high lymphocyte count (=1.3x10(9)/L) is an independent factor associated with rapid viral clearance (OR=7.62, 95% CI=1.15-50.34, p=0.035). CONCLUSIONS: The viral shedding exhibited different patterns during treatment. Immune insufficiency is responsible for the delayed viral clearance, suggesting that an immunomodulator should be considered to promote viral clearance in patients with low lymphocyte counts.