State Releases New Modeling Data from Colorado School of Public Health Scientists

The Colorado Department of Public Health and Environment (CDPHE) released additional modeling results from an expert group of public health scientists today. 

The Colorado School of Public Health (ColoradoSPH) assembled the expert group, which includes modeling scientists at ColoradoSPH and the University of Colorado School of Medicine at the CU Anschutz Medical Campus, as well as experts from the University of Colorado Boulder, University of Colorado Denver, and Colorado State University.   

Key staff from CDPHE and the ColoradoSPH presented information from the model’s results today.   

The latest Colorado model report is now available to the public, as are the presentation slides from today’s media briefing. All modeling reports are available on the Colorado School of Public Health’s COVID-19 website.   

The report provides an estimate of the degree of distancing that Coloradans have achieved so far. It also provides projections based on various policy scenarios around physical distancing, mask-wearing, and improved case detection and containment. The models are based on Colorado data and assumptions. 

Key findings from today’s report: 

• Mobility has continued to increase in Colorado (May 14, 2020 mobility report). Mobility, as measured by time spent away from home using anonymized and aggregated mobile device data, was lowest in early April and has been increasing steadily since mid-April.
• COVID-19 hospitalizations have declined in Colorado since mid-April as a result of the statewide Stay at Home order, which went into effect at the end of March. Researchers have only been able to measure one week of the Safer at Home policy period, so far. Whether the decline will continue is not certain.
• The estimated net effect of physical distancing, mask-wearing, and case isolation has been to reduce the reproductive number below 1 during the state-wide Stay at Home order, which ended statewide on April 26 and was extended to May 8 for six counties of the Denver metro region. 
• It is too early to say with confidence what the impact of the transition to Safer at Home has been on the course of the COVID-19 epidemic in Colorado. There is an approximate 13-day lag between infection and hospitalization, the indicator that guides the modeling. Additionally, the change to Safer at Home was not abrupt (e.g., retail did not open until May 4) and approximately 50% of the state’s population remained under Stay at Home through May 8 because of the extension of Stay at Home in six counties of the Metro-Denver region. The modeling team anticipates the earliest they will be able to make preliminary estimates as to the impact of the transition to Safer at Home statewide will be May 29. 
• The updated modeling results in this report continue to indicate that all control measures available, including relatively high levels of physical distancing need to be utilized. Increases in case detection and isolation, mask-wearing, and physical distancing of approximately 65% can prevent a surge in infections in excess of hospital capacity in the coming summer months. 
• If Colorado moves to lower levels of physical distancing (55%), older adults need to maintain physical distancing at the level seen during the Stay at Home in order to avoid exceeding hospital capacity. If only half of older adults adopt high levels of physical distancing under a 55% physical distancing scenario, the state is at risk of exceeding hospital capacity this summer. The modeling imply that policy measures should continue to emphasize the need for older adults to adopt measures to minimize their close physical contacts outside of their homes, thereby reducing their risk for infection, hospitalization, and death and preventing exceedance of hospital capacity. 
• Relaxation of physical distancing to lower levels (45%) is predicted to lead to a surge in sick people in excess of hospital capacity by mid-summer, even if implemented with mask-wearing, increased case detection and isolation, and higher levels of social distancing by all older adults.
• Around mid-August, the date at which schools generally open, the epidemic curves under all scenarios will rise. 
• The uncertainty highlighted in this report regarding the current course of the COVID-19 epidemic under Safer at Home will lessen over the coming days. Estimates of the trajectory of the outbreak under Safer at Home will be valuable for making decisions concerning further relaxation of social distancing.

The state will continue to review data and model findings as the pandemic continues to inform future policy decisions.