DENVER – Epidemiologists from the state and the U.S. Centers for Disease Control and Prevention (CDC) arrived in Grand Junction this week to investigate a growing number of outbreaks of the Delta variant at nursing homes in Mesa County – including some cases among fully vaccinated people.
Dr. Rachel Herlihy, the state epidemiologist, said cases of the Delta variant (B.1.617.2), first identified in India in December of last year, have been rapidly increasing and are now estimated to “be greater than 50% of cases” in Colorado.
Herlihy said the state was turning to the CDC to investigate how and why the Delta variant is spreading in Western Colorado, causing outbreaks at nursing homes, high hospitalization rates, as well as “some vaccine breakthrough cases” – cases of reinfection among people who’ve been fully vaccinated against COVID-19.
Data from the Colorado Department of Public Health and Environment (CDPHE) shows that for the week ending on June 13, cases of the Delta variant amounted to 75% of all cases across the state. A month prior, cases of the variant – believed to be the most transmissible variant yet – amounted to only 19.51%.
The first Colorado case of the Delta variant was officially identified in Mesa County on May 5. By June 22, the variant was present in 28 of Colorado’s 64 counties, according to the CDPHE.
“As of June 22, 54% of Delta variant cases in Colorado so far have been identified in Mesa County through genomic sequencing. In addition, Colorado is starting to see more cases of the Delta variant outside of Mesa County,” state health officials said in a news release.
CDPHE also said 90% of people admitted to the hospital with a confirmed case of COVID-19 — who may not have gone to the hospital seeking treatment for the virus — during the week of June 6-June 12, 2021, had not yet received a shot of the vaccine.
A breakdown of which variants are prevalent throughout the state show Mesa County has the highest prevalence of the Delta variant with 288 cases reported as of Thursday. It’s worth noting that the state doesn’t run genomic sequencing on all tests it receives, so the actual number of cases may be higher than what is officially reported.
Here are other counties with confirmed cases of the Delta variant in Colorado:
- El Paso County: 103
- Garfield County: 27
- Douglas County: 20
- Moffat County: 18
- Arapaho County: 12
- Boulder County: 12
- Adams County: 10
- Denver County: 6
- Weld County: 6
- Gunnis County: 5
- Fremont County: 3
- Montrose County: 3
- San Miguel County: 3
- Eagle County: 2
- Delta County: 2
- Jefferson County: 2
- Larimer County: 2
- Las Animas County: 2
- Bent County: 1
- Gilpin County: 1
- La Plata County: 1
- Pitkin County: 1
- Pueblo County: 1
- Rio Blanco County: 1
- Routt County: 1
- Saguache County: 1
- Segdwick County: 1
- Teller County: 1
Studies indicate the Delta variant causes more severe disease, with roughly double the hospitalization rate of the Alpha variant (B.1.1.7) which was first identified in the United Kingdom, according to the CDPHE.
Earlier this week, the New York Times reported other evidence suggests the variant may be able to partially evade protection provided by natural immunity after infection or protection provided by vaccination, and that the variant “may also render certain monoclonal antibody treatments less effective.”
Additionally, Israel’s health ministry director-general this week told state broadcaster Kan Bet that about 40 to 50% of new cases in the country associated with the Delta variant appeared to be among people who had been fully vaccinated, according to Business Insider, though cases were less severe.
Still, health experts stressed that getting vaccinated provides the best protection against severe illness, hospitalization and death from COVID-19.
“Current data suggests that getting vaccinated reduces the spread of infection, leading to fewer opportunities for new variants to develop and spread," state health officials said.
On Thursday, Delta County – which had no recorded cases of the Delta variant – reported its first two confirmed cases of the variant after genomic sequencing of test samples.