Revisiting SARS-CoV-2 environmental contamination by patients with COVID-19: The Omicron variant does not differ from previous strains

Abstract

SARS-CoV-2 Omicron strain emergence raised concerns that its enhanced infectivity is partly due to altered spread/contamination modalities. We therefore sampled high-contact surfaces and air in close proximity to patients who were verified as infected with the Omicron strain, using identical protocols applied to sample patients positive to the original or Alpha strains. Cumulatively, for all 3 strains, viral RNA was detected in 90 of 168 surfaces and 6 of 49 air samples (mean cycle threshold [Ct]=35.2±2.5). No infective virus was identified. No significant differences in prevalence were found between strains.

Keywords: Alpha; Omicron; SARS-CoV-2; air samples; original; surface contamination.

Figure 1

Patient viral load. Upper respiratory SARS-CoV-2 viral load in patients as determined by RT-PCR of nasal and mouth swabs (original strain n= 15, Alpha strain n=18, Omicron strain n=16). Data symbols present individual patient Ct values from 12-36 hours before sampling; black bars present patients’ group mean±SD. Statistical analysis carried by Prism 6 for Windows (GraphPad Software, San Diego, California, USA). Ct, cycle threshold; RT-PCR, reverse transcriptase–PCR.