Colorado’s COVID cases rise for a fourth week as BA.2 variant becomes dominant

Colorado’s COVID-19 cases have been rising slowly for four weeks, but the level of disease is still relatively low and it’s not clear how significant a wave the virus might be building up.

With the new BA.2 variant now dominant in the state, the Colorado Department of Public Health and Environment reported 3,560 confirmed new infections in the week ending Sunday, up from 2,649 a week earlier — a 34% increase.

Hospitalizations were slightly higher this week — with 88 people receiving care for the virus across the state as of Tuesday afternoon — than they were a week earlier, when officials reported 77 patients. The state is only publicly updating hospitalization numbers once a week, though, making it impossible to tell if that number is a one-day blip or part of a trend.

It’s possible more people will be hospitalized as the virus finds those who aren’t immune, said Beth Carlton, an associate professor of environmental and occupational health at the Colorado School of Public Health.

But the increase likely won’t be enough to threaten the state’s hospital capacity, she said.

“There’s no indication that this is going to be anything like prior waves,” Carlton said.

The percentage of tests coming back positive in Colorado also has risen, reaching an average of 4.98% over the last seven days. State officials tend to start getting concerned when that positivity rate rises above 5%.

Week-over-week increases in cases have been accelerating somewhat. The pattern is closer to what Colorado saw in the first weeks of the wave that started in summer 2021, rather than the off-the-charts growth drivsen by the virus’s omicron variant in January:

• Week ending April 3: 7.7% increase over the prior week
• Week ending April 10: 13.0% increase over the prior week
• Week ending April 17: 34.4% increase over the prior week

As of Wednesday, however, only three Colorado counties weren’t at a “low” level of COVID-19 transmission, according to the Centers for Disease Control and Prevention: Logan, Phillips and Sedgwick. The CDC recently updated its county dashboard to emphasize hospitalizations more than cases.

The number of active COVID-19 outbreaks dropped again, from 398 to 369. Most of that decrease came from a reduction in the number of K-12 schools reporting outbreaks.

The state lifted one of the few remaining COVID-19 restrictions on Wednesday by ending the requirement to wear masks on public transportation. A judge threw out the CDC’s requirement on Monday, and some Colorado transit systems already said they wouldn’t require passengers to mask up.

The good news is that the level of severe disease in Colorado is still low, Carlton said. The odds of running into someone who is contagious also are not high at this point, so people who are worried about getting infected don’t need to immediately change their behavior, she said.

“I think now is the time to just mentally prepare,” she said.

Some researchers have estimated about half of Americans already have been infected with omicron, limiting the impact of variants that aren’t substantially better at evading the immune system.