Colorado flu hospitalizations rise again, while COVID and RSV see decline

Colorado’s flu hospitalizations rebounded this week, dashing hopes that the unusually early season might already have peaked — though it’s still possible it could in the near future.

The state’s flu hospitalization rate rose again after falling the previous week, though it didn’t go as high as it was two weeks earlier. Hospitalizations of people with COVID-19 and respiratory syncytial virus, or RSV, dropped, though it’s not clear whether they will rise again as people travel and gather for the holidays, state epidemiologist Dr. Rachel Herlihy said.

“It’s difficult to predict what the trajectory of these viruses is going to look like,” she said Wednesday.

In addition to the three respiratory viruses, the state is monitoring severe infections with group A streptococcus bacteria, which have been more prevalent than in recent years, with a particular increase in children since November.

Still, the overall picture improved enough that the Colorado Hospital Association announced Tuesday that the state’s transfer center was deactivating, as demand for children’s beds stabilized.

The center, which had been used to match adult patients with beds during the worst COVID-19 surges, was reactivated on Nov. 9 because of unprecedented hospitalizations among children. Most of the crush was due to RSV, which typically causes colds but can be severe in infants and toddlers.

“Colorado hospitals are prepared to employ our capacity management tools, including the (transfer center), if we face another surge,” Jeff Tieman, president and CEO of the Colorado Hospital Association, said in a news release. “In the meantime, Coloradans can continue to protect themselves and the health care system by washing their hands, staying home when sick, and getting their flu shots and COVID boosters.”

Flu

The percentage of visits to emergency rooms and outpatient clinics in the Denver area that were for flu rebounded alongside hospitalizations, though the percentage of tests coming back positive dropped.

With COVID-19, a drop in the positivity rate was typically followed by declining cases and hospitalizations a few weeks later, but it’s not clear that the same relationship holds for flu, Herlihy said.

“We’re seeing a bit of a mixed trend,” she said.

Since the flu season started in early October, 1,733 people have been hospitalized in Colorado, and the Centers for Disease Control and Prevention estimated about 150,000 flu hospitalizations nationwide.

The flu hospitalization rate remains above normal for this time of year, but flu activity appears to be declining in the mid-Atlantic, the South and the Pacific coast region, according to the CDC. If that trend continues, it would suggest this year’s flu season was just early, rather than unusually long or severe.

Flu activity still appeared to be increasing in the region that includes Colorado, though, and the level of flu-like illness was “very high” as of Dec. 10, according to the CDC.

RSV and strep A

Hospitalizations for RSV continued to drop, finally going below last year’s peak this week. For the first time since mid-October, fewer than 100 people were newly hospitalized for RSV in the Denver area. The majority of the 2,026 people hospitalized since Oct. 1 are children.

“Our RSV numbers (this week) are much closer to what we would see in a typical season,” Herlihy said.

While the number of children with severe cases of RSV is decreasing, the Denver area has seen an increase in invasive group A strep infections, particularly in kids.

Strep A usually causes sore throats or mild skin infections, and also can cause scarlet fever. In rare cases, it can reach deeper into the body, causing pneumonia, bloodstream infections, toxic shock syndrome, or skin and muscle infections resulting in tissue death.

So far this year, the Colorado Department of Public Health and Environment has recorded 672 invasive strep A cases — about double the usual number in a year — including 32 in children and teens. Two of the children with strep A died, though their causes of death are still being determined.

It was unusual to see 13 children with invasive strep A infections since the start of November, said Dr. Sam Dominguez, an infectious disease specialist at Children’s Hospital Colorado. Strep A infections are easily treatable if caught early, he said, so parents should watch for symptoms, including difficulty breathing, lethargy, not eating or drinking, refusing to walk, a rash that’s spreading rapidly, or respiratory symptoms that suddenly get worse.

Many of the same symptoms are caused by other infections, but they’re serious enough that parents shouldn’t hesitate to bring their children in, Dominguez said.

“We need to get them into treatment as soon as possible,” he said.

COVID-19

Colorado’s COVID-19 hospitalizations dropped to 339 this week, down from 395 a week earlier. Cases and the percentage of tests coming back positive were declining steadily over the last few weeks, but have plateaued in recent days, Herlihy said.

About 9.3% of tests were positive over the last seven days, down slightly from 9.7% a week earlier. The state health department recorded 6,014 cases in the week ending Sunday, which was about 170 fewer than the previous week.

Virus concentrations in wastewater are still plateaued statewide, but that’s a lagging indicator, since people continue to shed detectable virus for some time after their infection, said Bailey Fosdick, an associate professor of biostatistics and informatics at the Colorado School of Public Health. The models suggest COVID-19 hospitalizations may have peaked and will likely decline in January, but they don’t specifically account for behavior changes around the holidays, she said.

“COVID-19 appears to have plateaued in Colorado and may have begun to decline,” she said. “There’s always a bit of uncertainty.”

COVID-19 deaths continued rising, with 65 recorded statewide in the week ending Dec. 4 — a 41% increase over the previous week. Data from more recent weeks is still coming in, making it difficult to tell if that trend has changed.

Only San Juan County was still listed as high-risk, meaning the CDC recommends that everyone there wear masks in indoor public spaces. Transmission was “high” or “substantial” in 54 of Colorado’s 64 counties, however, so people who don’t want to get the virus should consider taking precautions.