Colorado’s COVID cases tick up for first time since January, hospitalizations appear to be falling more slowly

Colorado’s COVID-19 cases and the percentage of tests coming back positive both ticked up over the last week, though they remained near all-time lows.

The Colorado Department of Public Health and Environment reported 2,488 new cases in the week ending Sunday, up from 1,598 the previous week — the first week-over-week increase in new infections since the omicron surge peaked in January.

But last week’s figure was similar to the number of cases seen in late June 2021, a relatively placid point in the pandemic.

The percentage of tests coming back positive rose slightly on Tuesday and Wednesday, though it remained well below the state’s goal of no more than a 5% positivity rate. The higher the positivity rate is, the more likely it is that the state is missing some cases.

Hospitalizations appeared to decrease more slowly this week, dropping from 151 on March 15 to 135 on Tuesday. The state’s decision to only update the number of people hospitalized with confirmed COVID-19 once a week made it more difficult to see a pattern, however.

It’s not clear if the slight rise in cases represents a real increase in transmission or a fluke, said Beth Carlton, an associate professor of environmental and occupational health at the Colorado School of Public Health. Right now, the odds of encountering the virus while going about daily life in Colorado are still low, but if the numbers continue to trend up, people might want to consider taking precautions again, she said.

“It is possible we’ll see an increase in cases and hospital demand in the days and weeks ahead,” though it’s very unlikely to be as severe as the most recent wave, she said.

The good news is that relatively few people are hospitalized for COVID-19 now, so if the virus does start spreading more widely, the system is in a better position to handle an increase, Carlton said.

The amount of the virus found in wastewater has remained relatively stable, according to the state’s tracking dashboard. The Centers for Disease Control and Prevention’s wastewater surveillance showed that virus levels were falling in 12 Colorado locations and rising in nine. Testing wastewater often provides the first clue to whether the virus is advancing or retreating, because people who are infected excrete the viral particles whether they have symptoms or not.

Public health experts have been watching a recent increase in COVID-19 cases and hospitalizations in the United Kingdom. It’s not clear how much of the increase is due to the BA.2 variant replacing omicron, the decision to lift all pandemic restrictions, or waning immunity.

The CDC estimates BA.2 now accounts for about 35% of cases in the country, though the state health department’s latest data showed the variant was only present in about 7% of Colorado samples as of late February. The variant is a cousin of omicron, and early data suggests people who recently had an omicron infection are unlikely to be reinfected within two months — though it’s not clear how much longer that immunity may last.

To figure out how concerning a variant might be, scientists consider how contagious it is, how well it gets around the immune’s systems defenses and how likely it is to make people seriously ill, Carlton said. For BA.2, the main concern is increased transmissibility, she said.

“BA.2 is just going to root out those remaining susceptibles” who weren’t recently vaccinated or infected with omicron, she said.