Colorado can expect a relatively small COVID-19 wave in the coming months as new variants take over, assuming the latest version of the virus isn’t significantly better at getting around the immune system.
The latest report from the state’s modeling team showed hospitalizations could peak between 550 and 650 by early summer, if the ascendant BA.2.12.1 variant is no more severe than omicron and no better at evading the immune system. That would be comparable to the peak of the spring 2021 wave, which was the second-smallest the state seen so far.
Much remains unknown about the new variant, however, and people’s decisions to use or forego precautions will influence how far the virus may spread.
The new modeling report estimated about one in every 375 residents is currently contagious, but that at least 80% of Coloradans have some immunity to current variants of the virus.
As of Tuesday afternoon, 88 people were hospitalized with confirmed COVID-19, which was a small increase from a week earlier. New admissions to the hospital with the virus edged up in the week starting April 10, but the difference was small enough that it may not be meaningful.
The Colorado Department of Public Health and Environment is only publicly reporting the number of COVID-19 hospitalizations once a week.
State epidemiologist Dr. Rachel Herlihy said Friday that cases have been in a “clear increasing trend” for about two weeks. Reported infections hit their low point in late March, with a seven-day average of 302 confirmed new infections per day. On Thursday, the average was 605 per day.
“Cases in Colorado continue to be quite low,” she said. “We have seen a doubling there in a couple of weeks.”
The positivity rate has also roughly doubled, from a seven-day average of 2.5% of COVID-19 tests coming back positive in mid-March to an average of 5.1% as of Thursday.
More people are taking home tests, which makes it difficult to compare the current numbers to what Colorado experienced in 2020 and 2021, Herlihy said. But combined with data from sampling wastewater and the small increase in hospitalizations, they paint a consistent picture of a modest increase in transmission over the last few weeks, she said.
“I do trust that these are true trends,” she said.
The previously dominant strain, known as BA.1, accounted for only about 19% of cases in Colorado as of April 10, which is the most recent date available. Prevalence of its cousin BA.2 actually dropped slightly, from about 76% to 70%, as the new BA.2.12.1 variant made in-roads. All three are in the omicron family.
BA.2.12.1 is more infectious than BA.2, which is itself more infectious than BA.1, Herlihy said. BA.2 isn’t significantly better at getting around the immune system than omicron and doesn’t cause more severe disease. There isn’t much data yet about how BA.2.12.1 is behaving, but so far there’s nothing signaling a worrisome change in severity or immune escape, she said.
“We believe that this variant, together with BA.2, is what’s leading to an increase,” she said.
BA.2 and BA.2.12.1 hit the East Coast first, so health officials are watching those states for clues, Herlihy said. Cases might have leveled out a bit in New York and a few other states, but it’s too early to know if that’s a trend, she said.
As of Friday morning, hospitalizations were up in 18 states and the District of Columbia, according to data compiled by The New York Times. So far, there are no reports of concerns about capacity.
Since not much is known about BA.2.12.1, the state is preparing for a variety of scenarios, Herlihy said. It’s unlikely Colorado could face anything worse than the most recent wave, she said.
“The data’s, overall, reassuring,” she said.
On Thursday, the health department sent out a statement reminding the public to make sure they’re up to date on COVID-19 vaccines. About 4 million people in Colorado have gotten two doses of the Pfizer or Moderna vaccine, or one Johnson & Johnson shot.
“Vaccination and testing remain important tools to slow the spread of COVID-19 and help avoid the worst health outcomes if people become infected,” Scott Bookman, the state’s COVID-19 incident commander, said in a news release. “Getting your recommended follow-up doses of COVID-19 vaccine and testing, staying home when you feel sick, and getting treatment early if you test positive are the best ways to continue protecting yourself and your community.”
Current federal guidelines recommend that almost everyone get a third shot and that people with compromised immune systems get a fourth and possibly a fifth. The guidance is more ambiguous for people older than 50 who have intact immune systems, but may also have other conditions. They are allowed to get a fourth shot, but the CDC hasn’t issued a strong recommendation.
Gov. Jared Polis sent a letter to President Joe Biden on Tuesday asking for “more urgency” from regulators to authorize a COVID-19 vaccine for children under 5.
In February, Pfizer pulled back its request that the U.S. Food and Drug Administration issue an emergency use authorization allowing its vaccine to be used in younger kids, citing disappointing results from a two-shot regimen. Earlier this week, Biden administration officials said vaccines might not be available for children under 5 until late June.
“Without access to vaccines for families with children under 5, many communities and kids remain vulnerable, leaving families and education settings vulnerable to disease transmission,” Polis wrote. “Ensuring the vaccine is accessible for families with children under 5 will help keep our kids in the classroom, give parents more peace of mind, and help put the pandemic behind us.”