Nasopharyngeal SARS-CoV-2 Viral Load Response among COVID-19 Patients Receiving Favipiravir.

Manosuthi, Weerawat; Jeungsmarn, Somlerk; Okada, Pilailuk; Suwanvattana, Pawita; Wongboot, Warawan; Thawornwan, Unchana; Charoenpong, Lantharita; Wiboonchutikul, Surasak; Uttayamakul, Sumonmal; Pongpirul, Wannarat A; Wachirapan, Apichat; Warachit, Paijit

We retrospectively studied nasopharyngeal SARS-CoV-2 viral load in the COVID-19 patients who were hospitalized between 13 January and 1 April 2020. Quantitative real-time reverse transcription-PCR were conducted with primers and probes targeting the ORF1ab and N genes. All patients were classified as 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 anti-viral medication. Of 115 patients, 38 (33%), 54 (47%), and 23 (20%) patients were in Group 1, 2, and 3, respectively. Median (IQR) baseline viral loads at days 0 of Group 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 at 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 reductions of mean viral loads from baseline among three groups at days 5 and 10 (P >0.05). By multiple logistic regression analysis, 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 the COVID-19 patients who received favipiravir-containing regimen.