A subvariant of the coronavirus’s omicron strain now accounts for a majority of the new COVID-19 infections in Colorado, sending cases ticking upward slightly.

But the state Department of Public Health and Environment says Coloradans as a whole still have population-level immunity, widespread in the wake of omicron’s emergence earlier this year. COVID-19 hospitalizations have not increased and are at their lowest levels in more than two years.

The omicron subvariant, designated officially as BA.2, accounted for more than 76% of new COVID-19 infections at the end of March, according to the most recent state data. It displaced the primary omicron strain, which has dominated COVID-19 cases in Colorado since mid-December, when it arrived in the state in full force.

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Cases in the state have ticked upward slightly this month, though they remain far below the levels seen at many other periods of the pandemic. According to data updated Thursday afternoon, Colorado has averaged about 412 new cases each day over the past week. That’s up from 326.7 two weeks ago and is slightly below the figure from March 14.

Still, the current average of 412 new daily cases is below any point between mid-July and mid-March. 

Hospitalizations, long considered among the most important metrics by state and public health authorities, have not ticked upward in Colorado. There were 77 Coloradans hospitalized with COVID-19 as of Wednesday, when data was most recently updated. That’s down slightly from last week and is nearly half the hospitalization total from mid-March.

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State and public health officials have said that BA.2 would likely become the dominant variant in Colorado, as it has in the country as a whole, and that it would lead to an increase in cases. But, they’ve said, the high level of immunity to omicron – estimated by researchers to be roughly 90% in Colorado – should help the state avoid another surge and provide for a period of pandemic calm that lasts at least into the early summer.