DENVER (KDVR) — Colorado health officials are preparing as the XBB.1.5 omicron subvariant of COVID is making its way into Colorado. Doctors say it may be the most contagious subvariant this far.

The Colorado Department of Public Health and Environment said XBB.1.5 now accounts for about 7% of cases in our region, but it is expected to take over based on what is happening in other parts of the country.

According to the Centers for Disease Control and Prevention, HBB.1.5 now accounts for about 28% of cases nationwide and it is the dominant subvariant in the Northeast.

“We’ve already seen some activity in Colorado. I suspect this will ramp up,” Dr. Jaya Kumar, the chief medical officer at Swedish Medical Center in Englewood, said.

She expects to see an increase in cases, but not an increase in the severity of illness.

“I expect the cases may go up in Colorado somewhat due to this subvariant, but I do not expect it to cause a steep rise in hospitalizations or severe illness or deaths,” Kumar said.

Colorado saw a tough start to the respiratory season last fall with RSV, flu and COVID cases flooding hospitals. As the new COVID subvariant begins to move its way in, some worry about the possibility of a new wave of infections.

“That’s a major concern, that we may see another surge between the post-holiday expected surge, and the fact that this new variant probably can escape immunity somewhat,” Dr. Sarah Rowan, an infections disease specialist at Denver Health said.

“So, for folks who have had COVID, they are still at risk. The vaccine does look like it’s highly effective against the development of severe disease, but vaccine rates are pretty low, so we definitely encourage anyone who hasn’t gotten that bivalent booster to go ahead and get that ASAP,” Rowan said.

The virus will continue to mutate, she said, so we must continue to take precautions.