SARS-CoV-2 Omicron variant shedding during respiratory activities.

BACKGROUND: As the world transitions to COVID-19 endemicity, studies focusing on aerosol shedding of highly transmissible SARS-CoV-2 variants of concern (VOCs) are vital for the calibration of infection control measures against VOCs that are likely to circulate seasonally.

OBJECTIVE: This follow-up G-II aerosol sampling study aims to compare the aerosol shedding patterns of Omicron VOC samples with pre-Omicron variants analyzed in our previous study.

STUDY DESIGN: Coarse and fine aerosol samples from 47 SARS-CoV-2 infected patients were collected during various respiratory activities (passive breathing, talking, and singing) and analyzed via reverse transcription quantitative polymerase chain reaction (RT-qPCR) and virus culture.

RESULTS: Compared to patients infected with pre-Omicron variants, comparable SARS-CoV-2 RNA copy numbers were detectable in aerosol samples of Omicron infected patients despite being fully vaccinated. Omicron-infected patients also showed a slight increase in viral aerosol shedding during breathing activities, and were more likely to have persistent aerosol shedding beyond 7 days post-disease onset.

CONCLUSION: This follow-up study reaffirms the aerosol shedding properties of Omicron, and should guide continued layering of public health interventions even in highly vaccinated populations.