Colorado’s COVID hospitalizations fall, but wastewater suggests more spread around Denver

Colorado’s COVID-19 hospitalizations dropped this week after a three-week plateau, though rising amounts of the virus detected in wastewater around Denver complicate an otherwise optimistic picture.

The Colorado Department of Public Health and Environment reported 159 people were hospitalized for the virus statewide as of Tuesday afternoon. The last time hospitalizations were lower was mid-May.

It’s not clear why hospitalizations stopped dropping for a few weeks while cases and the percentage of tests coming back positive kept falling, said Talia Quandelacy, an assistant professor of epidemiology at the Colorado School of Public Health. Hopefully, they’ll keep falling, though rising concentrations of the virus in wastewater are something to watch, she said.

“This is certainly a slightly larger drop than we’ve seen in the last month,” she said. “Overall, there’s still a bit of a mixed picture.”

An average of 5.1% of tests came back positive over the last week, down from about 5.6% a week earlier. When fewer tests come back positive, that’s generally a sign that the virus isn’t spreading as widely.

Cases dropped to 4,607 in the week ending Sunday, which was about 900 fewer than the week before — though it’s possible that low testing numbers on Labor Day were a factor. Outbreaks decreased for a seventh week, with 250 considered active as of Wednesday.

Wastewater told a more complicated story. As of Friday, samples from 12 systems, mostly along the Front Range, suggested the amount of virus in their wastewater was increasing. Another 12 showed decreases, 25 didn’t show any change and 11 had insufficient data.

Nationwide, cases and hospitalizations also have been trending down, according to data from The New York Times.

It’s not clear if any of the current variants are likely to change the picture. The Centers for Disease Control and Prevention estimated that BA.5 has topped out at about 88% of cases nationwide, while BA.4.6 is slowly making gains and accounts for about 9% of infections. In Colorado, BA.5 was found in about 89% of sequenced samples as of Aug. 21, and neither BA.4.6 nor BA.4 was in a clear pattern of growth.