I highly recommend Derek Lowe's post on it for some of the details. It links to the press release which contains this information showing it was very effective

I highly recommend Derek Lowe's post on it for some of the details. It links to the press release which contains this information showing it was very effective still starting at 5 days from symptoms onset: > Similar reductions in COVID-19-related hospitalization or death were observed in patients treated within five days of symptom onset; 1.0% of patients who received PAXLOVID™ were hospitalized through Day 28 following randomization (6/607 hospitalized, with no deaths), compared to 6.7% of patients who received a placebo (41/612 hospitalized with 10 subsequent deaths), with high statistical significance (p<0.0001). In the overall study population through Day 28, no deaths were reported in patients who received PAXLOVID™ as compared to 10 (1.6%) deaths in patients who received placebo. Those extra two days (three versus five) could make a huge difference.