Surveillance monitoring detects omicron variant in four Colorado wastewater systems

CDPHE: Fifth omicron case appears to be by local transmission
Posted at 9:35 AM, Dec 17, 2021

DENVER — Surveillance monitoring has detected the omicron variant in four Colorado wastewater systems, the Colorado Department of Public Health and Environment announced during a media briefing Thursday.

As of Thursday, the state has seen a steady decrease in the number of COVID-19 cases, as well as the positivity rate, meaning the number of PCR tests performed in the state that come back positive compared to the overall population. The state's hospitalization rate is also trending downward.

State Epidemiologist Dr. Rachel Herlihy announced a new omicron variant case, bringing the statewide total to five. This is the first case that appears to have been acquired in Colorado, she said.

"At this point, that's really the transition we're looking for is going from a place where we see sporadic imported cases of the omicron variant to a place where we see more local transmission. And then, of course, we'll be tracking the proportion of those specimens that are being sequenced to look at that transition overtime and where we start to see a growing percentage of those specimens sequencing as omicron," said Dr. Herlihy.

No further details regarding the patient were given.

Surveillance monitoring has detected the omicron variant in wastewater systems in Boulder, Aurora, Commerce City, as well as a system shared between Lakewood and Denver, Herlihy said. The surveillance programs had previously detected the omicron variant in Boulder's municipal wastewater system.

Early data suggests the omicron variant may have increased transmissibility and the possibility for increased reinfection and vaccine breakthrough infections, Herlihy said. However, data show the COVID-19 vaccine is highly effective in preventing severe disease, she added. There is also a high level of protection from infection and severe disease for vaccinated individuals who receive a booster.

At this time, there is mixed data regarding the severity of the omicron variant. A new report out of South Africa this week suggests a 30% decrease in severity associated with hospitalizations among adults, according to Dr. Herlihy. However, when it comes to children, scientists saw an increase in risk of hospitalizations, she said. This data is preliminary, Dr. Herlihy said, and needs to be further reviewed.

"It does look like omicron does have the ability to potentially replace or co-circulate with delta, but I think there's still a lot to try and understand and what the long-term trends are going to be," she said.

At this time, Colorado is not seeing a rapid increase in the number of omicron variant cases, according to Dr. Herlihy. The U.S. as a whole is also not seeing a rapid increase when compared to other countries.

"I think we have time over the next couple of weeks to really try and understand what the timeline might look like here in Colorado, and in the U.S. in general, for when we could expect to see a rapid increase in cases and ... how long that increase might last, how high that increase might go, what the hospitalization rate might look like," Dr. Herlihy said. "I think we're really trying to quickly understand all of those potential forecasts for the state based on what we're seeing in other places. So, I think at this point, lots of questions remaining, but ... based on what we're seeing elsewhere, I do expect that we will, over the next couple of weeks, continue to see an increase in omicron cases. I think we just don't know how quickly it is."