Most of metro listed with high, medium COVID-19 levels

Nearly all of the Denver metro area is now listed by the Centers for Disease Control and Prevention as having medium or high levels of COVID-19, as hospitalizations ticked upward again.

There were some signs this week that the latest COVID-19 surge, which is far milder than previous waves, was beginning to plateau.

But the state reported more than 2,200 cases Thursday for just the third time since Feb. 11. The positivity rate, which is the average number of COVID-19 tests that have been positive over the past week, held relatively steady for a few days but has since resumed its climb and now stands at 9.5%, the highest mark since Feb. 8.

As a result, more counties have seen their COVID-19 status downgraded by the CDC. Three counties in the state — Broomfield, Boulder and Jackson — are all rated as having high levels of transmission. Under that status, the CDC recommends universal masking indoors, regardless of vaccination status.

Another 14 counties, including Denver, Arapahoe, Douglas and Jefferson, are rated as having medium levels of transmission.

Hospitalizations, which are tracked on a weekly, rather than daily basis, also ticked up again this week. As of Wednesday, 163 people were hospitalized with COVID-19; 65% of them were hospitalized for the virus, and the rest were hospitalized for another reason and subsequently tested positive for it.

While that’s the highest number of reported hospitalizations since midMarch, it’s far lower than previous peaks, both in terms of its size and its rate of increase relative to new cases. Projections by a team of Colorado experts indicate hospitalizations may peak between 500 and 800 in coming weeks.

The current surge is being driven by a shifting array of subvariants of the virus. While omicron fueled the last major surge in December and January, its progeny are responsible for this latest wave. BA.2, a subvariant of omicron, displaced omicron as the dominant strain in mid-March. It’s now being slowly dethroned by another subvariant, BA.2.12.1, which accounted for nearly 39% of new cases during the second week of May.

Behind BA.2.12.1 is yet another omicron subvariant, BA.4, which had fueled a surge of cases in South Africa. Its presence is relatively minimal in Colorado, accounting for 3.18% of new cases as of May 8. But it’s believed to be more transmissible than other subvariants, and its presence may increase in the coming weeks.

Still, though, none of the subvariants have been proven to cause more severe disease than the original omicron strain, which itself was mild compared to previous variants. High, but decreasing, levels of population immunity from vaccinations and previous infections are also helping in keeping hospitalizations and case rates relatively low.