The CDC estimates Omicron is 95.4% of cases nationally for the week ending January 1st. Very tight 95% Prediction Interval of 92.9-97.0%. This matches a lot of the local S-gene target failure data around the country.
The week ending December 25th got revised up to 77.0% with a PI of 70.8-82.3%, so it likely became dominant in the week before Christmas. The week ending December 18th got revised up to 37.9% with a PI of 31.4-44.7%. Much tighter PIs than the initial estimates as more sequencing data comes in.
Lab data is suggestive that Omicron infection will protect against Delta reinfection, so Delta may be on its way out in the coming weeks. That would be very good for the long-term.
Protect yourself in the coming weeks. We are experiencing a lot of infections right now and healthcare systems are going to be strained between increased hospitalizations and staff absenteeism. Hopefully the Omicron wave peaks soon and recedes just as quickly as it surged.
By HHS region (95% PI)
Region 1: 82.4% (72.6-89.3)
Region 2: 98% (95.7-99.1)
Region 3: 93.8% (88.1-97.0)
Region 4: 97.5% (94.2-99)
Region 5: 93.7% (86.7-97.3)
Region 6: 98.2% (94.7-99.5)
Region 7: 77.4% (58.5-89.7)
Region 8: 95.4% (77.8-99.6)
Region 9: 95.0% (92.3-96.8)
Region 10: 94.9% (82.5-99.0)