Background There is no reliable microbiological marker to guide the indication and the response to antiviral treatment in patients with COVID-19. We aim to evaluate the dynamics of subgenomic RNA (sgRNA) in patients with COVID-19 before and after receiving treatment with remdesivir. Methods We included consecutive patients admitted for COVID-19 who received remdesivir according to our institutional protocol and accepted to participate in the study. A nasopharyngeal swab for qRT-PCR was collected at baseline, and after 3 and 5 days of treatment with remdesivir. Genomic and sgRNA were analyzed in those samples and main co-morbidities and evolution were collected for the analyses. The main outcomes were early discharge (≤10 days) and 30-day mortality. Results A total of 117 patients were included in the study, from which 24 had a negative sgRNA at baseline with a 62.5% (15/24) of early discharge (≤10 days) and no deaths in this group. From the 93 remaining patients, 62 of them had a negative sgRNA at day 5 with 37/62 (59.6%) of early discharge and a mortality of 4.8% (3/62). In the 31 patients subgroup with positive sgRNA after 5 days of RDV, the early discharge rate was 29% (9/31) and the mortality rate was 16.1% (5/31). In the multivariable analyses, the variables associated with early discharge were negative sgRNA at day 3, and not needing treatment with corticosteroids or ICU admission. Conclusions Qualitative sgRNA could help monitoring the virological response in patients who receive remdesivir. Further studies are needed to confirm these findings.

This study provides clinical and microbiologic data of an extended population of hospitalized patients for COVID-19 pneumonia who experienced treatment failure, detected by the presence of subgenomic RNA (sgRNA). The genetic variants found in the nsp12 pharmacological target of RDV bring into focus the importance of monitoring emergent mutations, one of the objectives of the World Health Organization (WHO) for health surveillance.