We retrospectively studied nasopharyngeal severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) viral load in coronavirus disease 2019 (COVID-19) patients who were hospitalized between January 13 and April 1, 2020. Quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) was conducted using primers and probes targeting the ORF1ab and N genes. All patients were classified in the following groups: Group 1: received favipiravir + chloroquine or hydroxychloroquine + lopinavir/ritonavir or darunavir/ritonavir for 5-10 days, Group 2: received chloroquine or hydroxychloroquine + lopinavir/ritonavir or darunavir/ritonavir for 5-10 days, and Group 3: no antiviral medication. Among the 115 patients, 38 (33%), 54 (47%), and 23 (20%) were in Groups 1, 2, and 3, respectively. The median (IQR) baseline viral loads on day 0 of Groups 1, 2, and 3 were 7.2 (6.0-8.1), 6.9 (5.8-7.8), and 6.9 (5.8-7.6) log10 copies/mL, respectively. The reductions of mean viral loads on day 3 from baseline were 2.41, 1.38, and 2.19 log10 copies/mL in the corresponding groups (P < 0.05). There were no differences in the reduction of mean viral loads from baseline among the three groups on days 5 and 10 (P > 0.05). Multiple logistic regression analysis showed that receiving favipiravir was associated with nasopharyngeal viral load reduction at three days (P = 0.001). Significant nasopharyngeal SARS-CoV-2 viral load reduction was achieved in COVID-19 patients who received a favipiravir-containing regimen.
Keywords: COVID-19; favipiravir; treatment; viral load.