Data from multiple in vitro studies confirmed that Veklury® (remdesivir) retains antiviral activity against 10 SARS-CoV-2 variants, including Alpha, Beta, Gamma, Delta and Omicron.

In October 2020, the Food and Drug Administration (FDA) approved Veklury, a nucleotide analogue with broad spectrum antiviral activity, for the treatment of COVID-19 in patients 12 years of age and older weighing at least 40kg who require hospitalization. In January 2022, the FDA expanded the approval to include treatment of COVID-19 in nonhospitalized patients with mild to moderate disease who are at high risk for progression to severe disease.

To assess in vitro antiviral activity, a nucleoprotein enzyme-linked immunosorbent assay (ELISA) and plaque reduction assay were used to understand the susceptibility of 10 current and former SARS-CoV-2 variants to Veklury and its parent nucleoside, GS-441524. Findings showed a similar antiviral activity level against the variants and the ancestral A lineage isolate (WA1 strain). Moreover, all major variants of concern, including Delta and Omicron, were found to remain fully susceptible to Veklury.  

In a press statement, Gilead noted that “the study analyzed nearly 6 million publicly available variant isolate sequences and confirmed that the nsp12 protein, the RNA polymerase target of Veklury, is highly conserved across all variants.” Veklury also retained potency against all viruses containing nsp12 mutations. 

Results from the Company’s studies were consistent with other in vitro studies independently conducted by researchers from institutions in other countries, including Belgium, Czech Republic, Germany, and Poland.

“These results provide evidence of the consistent and durable antiviral activity of remdesivir across known variants that have emerged throughout the pandemic, including Omicron and support its continued use for the treatment of COVID-19 for current SARS-CoV-2 variants,” said Tomas Cihlar, Senior Vice President of Virology Research, Gilead Sciences. “Now with a new version of Omicron (BA.2 subvariant) increasing in circulation around the world, these latest data also suggest that remdesivir will retain antiviral activity against this new subvariant because the viral RNA polymerase that remdesivir targets does not contain any additional unique mutations.”


  1. Veklury® (remdesivir) retains antiviral activity Against Omicron, Delta and other emergent SARS-CoV-2 variants in multiple in vitro studies. News release. Gilead Sciences, Inc. February 11, 2022. Accessed February 15, 2022.
  2. Pitts J, Li J, Perry JK, et al. Remdesivir and GS-441524 retain antiviral activity against Delta, Omicron, and other emergent SARS-CoV-2 variants. bioRxiv. Published online February 10, 2022. doi:10.1101/2022.02.09.479840