After five months of nearly uninterrupted surges, Colorado’s COVID-19 case and hospitalization rates have tumbled to their lowest levels since August and the vast majority of the state is projected to be immune to the virus’ dominant strain.

Between Colorado’s relatively high vaccination rate and the sheer number of residents who have been infected with the omicron variant, 90% of the state is believed to be immune to the strain, state officials told reporters Thursday morning. Even more are projected to be immune to hospitalization from the strain, which has accounted for the vast majority of infections here since the latter half of December.

The result, in the near term, is a continued “dramatic” decline in cases and hospitalizations, said Scott Bookman, Colorado’s COVID-19 incident commander. At the omicron wave’s peak a month ago, 1,676 Coloradans were hospitalized with the virus, the most since fall 2020. In the 30 days since, that number has plummeted to 641, the lowest since Aug. 20, when the delta wave was beginning to pick up steam.

Rachel Herlihy, Colorado’s state epidemiologist, told reporters that projections indicate hospitalizations here could drop to 250 or fewer by the end of February. The state has not had 250 or fewer hospitalized COVID-19 patients since Oct. 7, 2020, when Donald Trump was still president and was in the process of recovering from a COVID-19 infection himself. 

The state has averaged 1,499 new COVID-19 cases over the past week, a fraction of the 13,841 average recorded on Jan. 10. The last time the state’s daily average was below 1,500 was also Aug. 20.

The high levels of immunity among the population mean that cases and hospitalizations should continue to fall and stay low until at least the early summer, Herlihy and Bookman said. It’s unclear how omicron immunity will wane, and experts have not projected population-level protection beyond early summer. Herlihy said making predictions beyond that is difficult because of outstanding questions about waning immunity with omicron, but those available projections do expect immunity to begin dropping by June.

Still, the good news — high levels of immunity and dropping COVID-19 metrics — should herald a quiet spring for a state that faced an extended delta wave beginning in August that rolled right into omicron in December. Colorado officials announced Thursday an end to the crisis standards of care for both hospital staffing and ambulances, shifting two critical pieces of the broader health care infrastructure into their pre-surge status quo.

The one outstanding variable that could disrupt the projected tranquility is the emergence of another variant, Herlihy said. If a new strain appeared and had the ability to escape prior immunity, that would “change this picture dramatically,” she said.

The state is planning to begin extricating itself from parts of the COVID-19 pandemic that have become accepted parts of everyday society — mass testing sites and vaccination clinics in parking lots, for instance. Bookman said that work is ongoing and being evaluated, but he also said Colorado officials “stand ready to continue our response and scale to meet” any future demand.