Higher SARS-CoV-2 shedding in exhaled aerosol probably contributed to the enhanced transmissibility of Omicron BA.5 subvariant.

The global pandemic of the BA.5 subvariant had moved from prediction to reality. In this study, we compared SARS-CoV-2 aerosol emissions from patients with BA.2 or BA.5 subvariant infection. First, patients with BA.2 subvariant infection had higher upper respiratory viral loads than patients with BA.5 subvariant infection. However, the average breath emission rate (BER) of patients with BA.5 subvariant infection, which represented the concentration of exhaled SARS-CoV-2 aerosols, was nearly 40 times higher than that of patients with BA.2 subvariant. Second, aerosols exhaled by patients with BA.5 subvariant infection exhibited SARS-CoV-2 RNA detection positive rate than patients with BA.1 or BA.2 subvariant infection. Meanwhile, for BA.5 subvariant infection, patients that exhaled infectious SARS-CoV-2 aerosols accounted for 14.8% of all patients. Third, since the onset of COVID-19, the SARS-CoV-2 RNA detection signals of throat swabs showed a gradual decline trend, although the decline process was accompanied by fluctuations. Overall, the monitoring of infectious SARS-CoV-2 aerosols may provide the data support for the transmissibility evaluation of the Omicron BA.5 subvariant. This article is protected by copyright. All rights reserved.