[berenza]

"Inclusion criteria were an age of 18 years or older; presentation to an outpatient care setting with an acute clinical condition consistent with Covid-19 within 7 days after symptom onset;"

I don't know if "up to 7 days after symptom onset" qualifies as early antiviral treatment.

hastily-googled citations:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7323384/

https://www.cdc.gov/flu/professionals/antivirals/summary-cli...

https://www.science.org/doi/10.1126/sciadv.abc7112

[Gatsky]

Other effective early interventions work within this timeframe eg sotrovimab.