CDC and state disagree on the number of COVID variants in Colorado

This 2020 electron microscope image made available by the Centers for Disease Control and Prevention shows SARS-CoV-2 virus particles which cause COVID-19. According to research released in 2021, evidence is mounting that having COVID-19 may not protect against getting infected again with some of the new variants. People also can get second infections with earlier versions of the coronavirus if they mounted a weak defense the first time. (Hannah A. Bullock, Azaibi Tamin/CDC via AP)

by: DJ Summers

Posted: Apr 7, 2021 / 10:49 PM MDT

Updated: Apr 12, 2021 / 04:37 PM MDT

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DENVER (KDVR) — Variants are in the newly vaccinated air.

Researchers recently found Colorado’s first instance of the COVID variant first spotted in Brazil. The Colorado Department of Public Health and Environment (CDPHE) and the U.S. Centers for Disease Control and Prevention (CDC) classify this a “variant of concern” along with the variants first found in California and London.

This definition applies to variants for which there is “evidence of an increase in transmissibility, more severe disease (increased hospitalizations or deaths), significant reduction in neutralization by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures.”

The CDC and state health department have different estimates of what percentage of Colorado’s cases are variants.

Up to 43% of Colorado’s cases are variants, CDC estimates say. Seventeen percent of Colorado’s cases are the B.1.1.7 variant, 26% are the two California variants, 0.3% is the Brazil variant. The rest come from “other lineages.”

According to these figures and the state’s cumulative counts from those dates, that would mean about 12,000 variant of concern cases.

The CDC’s numbers say Colorado has some of the county’s highest levels of variants of concern.

There have been 40 U.S. states where the B.1.1.7 variant first found in London has been found. The CDC found that 17% of the samples taken from Colorado were of the B.1.1.7 variant, the 10th highest proportion.

The two variants first identified in California are 26% of Colorado’s COVID cases, the sixth-highest proportion.

The CDC says its estimates “may not match cases reported by states, territories, tribes, and local officials.”

This is true in Colorado’s case. CDPHE estimates are significantly lower than the CDC’s.

Part of reason why is the different methods. The CDC selected at least 300 random samples gathered in a four-week window ending March 13. The CDPHE’s search for variants is ongoing. It tests 5% of the state’s positive cases and confirms variants through genome sequencing.

“As of our April 6 data update, we have confirmed 1,316 cases involving a variant of concern,” wrote the CDPHE.

The CDPHE’s number would make variants of concern present in 1% of the state’s new COVID cases since Dec. 29, 2020, when the first variant was discovered in Colorado.