Airborne SARS-CoV-2 in patient rooms during the Omicron wave compared to early variants

The covid-19 pandemic was characterized by a series of variants of concern, different strains of SARS-CoV-2 which had a serious impact on transmission. One of these, denoted Omicron, dominated in early 2022 and caused covid-19 cases to soar. The increased transmission during the Omicron wave triggered hospitals to further strengthen airborne precautions. The reason for this surge in cases during Omicron is still not clear, but proposed explanations include increased emissions of virus in exhaled air, improved viability in air, or structural mutations of the spike protein that promote infection efficiency at the target cells.We have previously reported findings of airborne SARS-CoV-2 in patient rooms during the primary wave, when the ancestral strain was dominant, and during the introduction of the Alpha variant. The aim with this study was to compare the positivity rate of air samples in patient rooms during the Omicron and ancestral waves.