COVID-19 Regional Models for Colorado


View the most recent COVID-19 Regional Model report.

Scroll down for reports on specific regions.

The regional epidemic models use methods similar to that used for the state-level model. Estimates are presented for the 11 Local Public Health Agency (LPHAs) regions in the state and for 8 selected counties with populations that are sufficiently large to allow for county-level estimates. Scroll down for more information on how counties are grouped into regions.

We use the model as well as COVID-19 hospital and vaccination data to generate four measures for each region. These measures can be used to gauge the current state of the SARS-CoV-2 epidemic in each region.

The effective reproduction number (Re) is a measure of how rapidly infections are spreading or declining in a region.

Infection prevalence is an estimate of the portion of the population currently infected and capable of spreading infections. It can be used to gauge how risky contacts are.

The percent of the population fully vaccinated to date is based on data provided by CDPHE and includes all people who have received one dose of Johnson and Johnson or two doses of Pfizer or Moderna vaccine. Because it takes approximately a month to develop immunity, some of these individuals may not yet be immune to the virus.

The percent of population estimated to be immune is estimated from the number of individuals immune due to vaccination combined with the individuals immune due to infection. These estimates account for the time between vaccination and immunity and the efficacy of the vaccine. As the immune population grows, due to vaccination or prior infection, the spread of infection slows.


Snapshot of Regional Model Results

The estimated effective reproductive number, prevalence of infections, percent of the population immune and vaccinated to date by region. These metrics are estimated using hospitalization data from the Colorado COVID Patient Hospitalization Surveillance (COPHS). Effective reproductive number (Re) reflects hospitalization data through 07/05/2021. The prevalence of infections and percent of the population immune is estimated for 06/28/2021. The percent vaccinated estimates are based on data provided by CDPHE through 07/11/2021 and reflect the proportion of the population that is fully vaccinated as of that date.


The map below shows the 11 LPHA regions for which estimates were generated. Regions in yellow (effective reproductive number > 1), orange (prevalence > 1%), or red (both effective reproductive number > 1 and prevalence > 1%) indicate areas of concern.

Local Public Health Agency Regions

Click on the LPHA regions and counties below to access estimates from the regional model.

Note: Clear Creek, Gilpin and Jefferson counties are modeled as a single unit due to the small population of Clear Creek (9,379 residents) and Gilpin (5,924 residents) – populations too small to allow for stable estimation.


Access previous COVID-19 State and Regional Model reports.

Download the report on the definition the local public health agency regions.

Download the documentation for the regional model.

View the code used in the regional models.