Review 2: "Duration of viable virus shedding in SARS-CoV-2 omicron variant infection"

RR:C19 Evidence Scale rating by reviewer:

• Reliable. The main study claims are generally justified by its methods and data. The results and conclusions are likely to be similar to the hypothetical ideal study. There are some minor caveats or limitations, but they would/do not change the major claims of the study. The study provides sufficient strength of evidence on its own that its main claims should be considered actionable, with some room for future revision.

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Review:

The manuscript by Boucau and co-workers demonstrated that, although SARS-CoV-2 Omicrom infection `shows a clearly different dynamics in terms of incubation period and transmission rates compared to the previous variants, no distinction was observed in terms of the time of virus shedding in the upper respiratory tract and time of infectious virus recovery in cell culture. Although the study was performed with a limited amount of samples (37 Delta and 19 Omicron variant symptomatic infections), the data presented is very relevant for the actual phase of the COVID-19 pandemics since it demonstrates that the virus's ability to invade and replicate in the upper respiratory tract does not change with the Omicron variant, going against the recommended rule of resuming isolation after 5 days of symptoms onset or of a positive SARS-CoV-2 test. The fact that 50% of the individuals still harbor infectious at five days post-infection and 25% at eight days is striking since it correlates with the possibility of continuous Omicron transmission after 5 days of symptomatic infection. Equally important is the demonstration that Ag-RDT positivity correlates mainly with viral load regardless of the variant analyzed. Also, discordancy between qRT-PCR results and Ag-RDT results mainly occurs 6-10 days after symptom onset, which correlates with an important decrease in the presence of cultivable virus. Thus, the data presented are sound and highly relevant for the field, especially because it clarifies the concerns regarding the Omicron variant, and would help in the management of SARS-CoV-2 infection.