Virus Outbreak Colorado

A man checks in for a COVID-19 booster shot at a pharmacy in a grocery store Wednesday, Nov. 3, 2021, in downtown Denver. 

Despite a slight uptick earlier this week, COVID-19 cases in Colorado remain near their lowest levels of the pandemic, and experts say the spread of a new subvariant of the virus in Europe is unlikely to lead to an imminent surge here.

Globally, cases have begun to tick upward again after weeks of declines, according to the World Health Organization, fueled in part by the emergence of a subvariant of omicron, known as BA.2.

The strain is at least 30% more transmissible than omicron, which burned through Colorado in December and January and sent case rates skyrocketing. In the United States, BA.2 is accounting for higher proportions of cases and is leading to fears that a new surge could be on the horizon.

Cases had been steadily falling in Colorado for weeks, since the omicron wave peaked in mid-January. As of Thursday morning, Colorado had reported about 310 new COVID-19 cases each day over the past week. That's up from a week ago but still far below nearly any other point since September 2020. Hospitalizations had fallen to 135 by Wednesday afternoon, though an exact tally is difficult to deduce: The state is now reporting its hospital metrics on a weekly basis, rather than daily.

Colorado confirmed its first case of BA.2 at the end of December, state officials previously told reporters. As of Tuesday, the state Department of Public Health and Environment said it had confirmed 294 positive BA.2 tests. Nineteen of the state's 35 wastewater collection sites had traces of BA.2 in their samples. 

"The number of positive tests with BA.2 has steadily increased in Colorado," the agency said. "Based on data from other US states, we expect that the proportion of tests that are BA.2 will increase."

In Colorado, officials have said that high levels of immunity — from omicron's wide spread and from high vaccination rates — should insulate the state from a future surge for at least a few months. Experts said this week that cases may tick upward because of BA.2, but broad immunity should continue to help keep case rates low here in the near term.

"I think that we should be largely protected by the present level of population immunity, but there is the potential for BA-2 to slow decline or cause an uptick," Jon Samet, the dean of the Colorado School of Public Health, said in an email. "Some data would suggest that may be happening, but nothing definite. So, still substantial uncertainty and the possibility of an uptick, but I don’t anticipate a sharp rise in the epidemic curve."

Beth Carlton, an epidemiologist also with the public health school, echoed that sentiment. She, like the state health department, expects BA.2 to account for a growing proportion of COVID-19 cases here in the coming weeks. Citing data from the Centers for Disease Control and Prevention, she said BA.2 accounted for roughly 21% of new infections in Colorado's region, compared to 35% nationally, indicating we're behind broader trends.

She said European cases and hospitalizations are increasing, an expected side effect of a more transmissible strain spreading. 

"What happens in the UK has typically been a good indicator of what might happen in the US, but not always," Carlton continued. "So, it’s reasonable to expect SARS-CoV-2 cases and hospitalizations could increase in the weeks ahead from the very low levels we are at now. But it’s unlikely that we will see a surge akin to what we experienced in November due to Delta or January due to Omicron because we have very high levels of immunity in the population."

She thinks of BA.2 "as being the subvariant that seeks out the remaining people who are susceptible to omicron," which, she said, is another reason for people to stay up-to-date on their vaccinations.

Against the backdrop of BA.2's rise are funding concerns at a federal level related to the pandemic. Congress pulled another round of COVID-19 funding from a recent funding measure. The White House has said it's running out of money to pay for vaccines, testing and treatment. If a fourth shot is recommended for all Americans, as drugmakers are beginning to say it should be, then the government will not have enough money to pay for those doses. 

Those funding concerns are starting to be felt in Colorado: The state's allocation of two monoclonal antibody treatments — purchased and distributed by the federal government — were 35% lower this week than last week, according to the state health department, because of the lack of federal funding.

Fortunately, because COVID-19 cases have fallen off so significantly since January, the agency said it was still able to accommodate all orders from providers. 

Samet said the nation needed "to address systems for contending with the pandemic, including logistics and stockpiles," now, when the pandemic is in a relative lull. 

"If we don’t do the basic work needed for preparedness," he said, "I will be concerned with what might happen with the next surge."

The Los Angeles Times and The Associated Press contributed to this report. 

Health reporter

Seth Klamann is the health reporter for the Gazette, focused on COVID-19, public health and substance use. He's a Kansas City native and a University of Missouri alum, with stops in Wyoming, Omaha and Milwaukee before moving to Denver.