Colorado’s hospitalizations from COVID-19 and other respiratory diseases continued to decline this week, but it’s too early to say that the winter virus season is ending.
Flu activity is still relatively high in the state, although it’s decreasing, and it’s not clear if the latest COVID-19 variant could cause another surge.
The picture is clearest for respiratory syncytial virus, which is unlikely to cause another significant wave of illnesses this winter, said Beth Carlton, an associate professor of environmental and occupational health at the Colorado School of Public Health. RSV typically causes colds, although it can be severe in infants, toddlers and older people.
In the past week, 37 children and 19 adults were admitted to Denver-area hospitals with RSV, which was the lowest number since early October, according to the Colorado Department of Public Health and Environment. (The health department doesn’t track statewide numbers.)
Since the start of October, 2,318 people have been hospitalized with RSV — the majority of them children. That created unprecedented demand for children’s beds in November. Hospitals that normally would transfer teenagers continued to treat them, reducing the strain on the health care system.
Fortunately, it didn’t coincide with a particularly severe wave of flu or COVID-19.
Colorado’s flu hospitalization rate dropped by half over the past week, after a month without a clear direction. The state health department reported 198 people were admitted to hospitals with the flu in the week ending Saturday, bringing the total since October to 2,666.
Visits to primary care providers and emergency rooms for flu-like illness also dropped sharply in the past week. So did the percentage of flu tests coming back positive. Overall, that’s encouraging, but flu had two peaks last year, Carlton said.
“This has been such an atypical year for flu, I don’t think anyone’s willing to say we’re done,” she said.
Flu activity remains “high” in most of the country but was trending down as of Dec. 31, according to the Centers for Disease Control and Prevention. Assuming there isn’t another peak, that would suggest this flu season was simply early, not unusually long or severe. Still, an estimated 230,000 people have been hospitalized and 14,000 have died nationwide.
“The risk of encountering someone with influenza is high, but I’m less concerned about hospital strain” than earlier in the season, Carlton said.
Colorado’s COVID-19 hospitalizations also dropped, for the fifth week in a row. The state health department reported 245 people were hospitalized with the virus as of Tuesday afternoon, down from 281 a week earlier. Still, it’s a good idea to get the booster if you haven’t had a shot or an infection recently, to reduce your risk of severe disease, Carlton said.
Other data also suggested infections are becoming less common. Viral concentrations were falling in 17 wastewater utilities’ watersheds, rising in nine and stable in 29.
About 7.9% of COVID-19 tests came back positive in the past seven days, down slightly from an average of 8.4% a week earlier. Cases also dropped, with 3,136 in the week ending Sunday, compared with 3,905 a week earlier.
One possible exception to the pattern of improvement is the San Luis Valley. Although most of Colorado is at the low or medium risk level, based on COVID-19 cases and hospitalizations, the CDC labeled six counties as high risk: Alamosa, Conejos, Costilla, Mineral, Rio Grande and Saguache.
It’s not clear if the latest variant could change the pattern. XBB.1.5 has taken over faster on the East Coast than previous variants, through some combination of immune evasion and increased contagiousness.
The question, however, isn’t whether XBB.1.5 can outcompete other variants, but whether it’s different enough to find susceptible people that BQ.1 and BQ.1.1 — the variants currently dominating in Colorado — couldn’t. Right now, there just isn’t enough data from the East Coast to be sure, especially because the Northeast was seeing an increase in hospitalizations when XBB.1.5 came on the scene, Carlton said. There are some signs hospitalizations could be plateauing in the Northeast, but it’s also possible that just reflects delayed reporting, she said.
“I’m hopeful maybe next week we’ll have a better answer,” she said.
