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When Gov. Jared Polis announced on Monday that he will allow his stay-at-home order to expire on April 26, he talked about the state entering into a new phase in its work to contain the coronavirus.

“We now have to figure out how to create a sustainable way of life for the future,” he said.

But a fine-print reading of new modeling data released Monday, as well as statements by Polis and health officials, shows just how much uncertainty comes with creating this new way of life — and how easily the virus could still rise up and overwhelm our state’s health system if we get it wrong. So that means, for many, the new phase will look a lot like the previous phase: You’re going to be spending lots of time at home.

As Colorado prepares to open back up amid a still very active pandemic, here are some of the unknowns that remain and why they matter.

Will cases spike?

According to new modeling projections released Monday, Colorado has bent the curve on COVID-19, the disease caused by the new coronavirus.

This graph, taken from a Colorado Department of Public Health and Environment presentation on new modeling data on April 20, 2020, shows how social distancing measures impacted the spread of the COVID-19 virus. Researchers with the Colorado School of Public Health estimate that Colorado achieved between a 75% and an 80% reduction in social interaction during the period of the statewide stay-at-home order. (Screenshot)

But, unless we absolutely nail the reopening strategy these next few months, the peak for the number of hospitalizations (and, by inference, deaths) is still ahead of us. Maybe far ahead of us. Depending on the scenario, the projections estimate the peak might fall anywhere from early July to late December.

In many of the scenarios modeled, the state also still won’t have enough critical-care hospital beds to treat everybody who needs that level of care — meaning people who could be saved would end up dying. This capacity issue is the “North Star” guiding the state’s public health efforts on coronavirus, said Jill Hunsaker Ryan, the executive director of the Colorado Department of Public Health and Environment. She said the state could clamp back down on restrictions if cases start to get out of hand.

In recent press briefings, Polis has made clear he does not see his job going forward as preventing as many people as possible from getting sick. He has instead talked about being able to reopen the state’s economy incrementally while giving everyone who gets infected a “fighting chance” to beat the virus.

There’s only one scenario in the modeling projections released Monday where the state’s peak for COVID-19 hospitalizations is already behind us, but it will take massive public commitment to pull off.

Dubbed “Scenario F,” it’s a throw-everything-at-it approach. It requires Coloradans to wear masks in public, for the state to run an effective testing and contact-tracing system, for older adults to stick to stay-at-home levels social distancing and for everybody else to maintain a 65% reduction in social interactions for months into the future.

These graphs, taken from a Colorado Department of Public Health and Environment presentation on new modeling data on April 20,2020, show projected hospitalizations (left) and critical-care bed need (right) due to COVID-19 under one restrictions scenario. The white, red and green lines project case numbers under the scenario at various levels of social distancing. The straight white line in the graph on the left shows the state’s critical-care hospital bed capacity, which the model puts at about 1,800 beds. (Screenshot)

Will Coloradans maintain enough social distancing to make a difference?

When it comes to interventions, the level of social distancing is really what has the biggest impact.

Even in Scenario F, the state’s critical-care hospital bed capacity — which the model pegs at 1,800 beds — will be overwhelmed if Coloradans hit only a 45% reduction in social interactions. (These reductions are compared to normal, so what life looked like in January.)

But there are other scenarios that keep the state within its hospital capacity so long as Coloradans maintain at least a 65% reduction in social interactions.

This chart, taken from a Colorado Department of Public Health and Environment presentation on new COVID-19 modeling data on April 20,2020, shows the number of critical-care hospital beds the state is expected to need under various restriction scenarios. The model puts the state’s current critical-care bed capacity at 1,800, so the numbers circled indicate scenarios where the state could stay below that capacity. (Screenshot)

Likewise, if the state gradually relaxes its social distancing in the summer, the health care system will still be overwhelmed, according to the modeling projections.

This graph, taken from a Colorado Department of Public Health and Environment presentation on new COVID-19 modeling data on April 20,2020, shows how cases would rise if social distancing restrictions are gradually phased out. (Screenshot)

So, what does a 65% reduction in social interactions look like going forward?

Health officials can’t really say right now. When asked about it during a call with reporters this week, Dr. Rachel Herlihy, the state epidemiologist, said they’ll be learning as they go.

“We’ve laid out the numbers and now need to figure out the policies and strategies that plug into those numbers and make things work going forward,” she said.

Dr. Rachel Herlihy, Colorado’s state epidemiologist, speaks to reporters at the governor’s mansion in downtown Denver on Monday, April 20, 2020. (Jesse Paul, The Colorado Sun)

Dr. Jonathan Samet, the dean of the Colorado School of Public Health and one of the researchers who built the state’s model, said his team estimates Colorado achieved a 75% to 80% reduction in social interactions during the stay-at-home order. So dialing it back to 65% isn’t relaxing by that much.

Polis has previously said the state hit around a 60% reduction in social interactions during the period just before the stay-at-home order — when schools, bars, restaurants, gyms and casinos all were closed.

So it’s really unclear how much of life can return while still maintaining that 65% social distancing. During the call with reporters, Samet talked optimistically — though cautiously — about whether Colorado could be open this summer for tourists. Ryan jumped in.

“Correct me if I’m wrong Dr. Samet,” she said, “but at a 65% level of social distancing, you’re just not having tourists in the areas. It’s too high of a level.”

“I would suspect that would be the case,” he said. Then, later, he added: “The same issue comes up with ski season.”

This is a picture of CDC’s laboratory test kit for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). CDC tests are provided to U.S. state and local public health laboratories, Department of Defense laboratories and select international laboratories. (Provided by the CDC)

Will there be enough testing to know what’s going on?

For weeks, Colorado officials have been talking about expanded testing and a strengthened contact-tracing system as pillars of a post stay-at-home world. But both of those pillars are still under construction.

The state is in the process of hiring additional contract-tracers to hunt down potential new cases and isolate them before they infect others. Ryan said the state hopes to ramp up its contact-tracing system to be able to handle 500 cases a day “in the next four to six to eight weeks.”

Jill Hunsaker Ryan, who leads the Colorado Department of Public Health and Environment.

And widespread testing largely remains aspirational — though some local communities, like Eagle County, have better systems in place for their residents.

“We don’t have the supplies for that as we sit here today, but we still hope to get that system in place,” Ryan said.

So that lack of widely available, fast and reliable testing is another reason why life after the stay-at-home order will continue to feature a ton of staying at home. Without having a precise tool to identify and isolate people infected by the virus, Colorado must use blunter instruments.

“To be clear,” Polis said Monday, “if we had all the testing in the world right now — all the testing we wanted — it might mean that the social distancing, instead of 60 to 65%, maybe it would be 50%. And we would love that. You could do more at 50% than you can at 60-65%. But we don’t have all the testing we want. We’re rapidly scaling it up.”

Gov. Jared Polis before speaking to reporters at the governor’s mansion in downtown Denver on Monday, April 20, 2020. (Jesse Paul, The Colorado Sun)

Will people who recovered from the virus remain immune to it?

This last one certainly isn’t in the control of state health officials, but it does have the potential to throw the state’s model way out of whack — for better or for worse.

The model uses a framework called SEIR — for susceptible, exposed, infected and recovered. The framework is basically a giant sorting machine, drawing from a gradually shrinking pool of susceptible individuals.

This chart, taken from a Colorado Department of Public Health and Environment presentation on new modeling data on April 20, 2020, explains the framework for the state’s model for projected the impacts of COVID-19. The framework starts with a large, but shrinking, group of people who are susceptible to catching the virus and assumes that people who recover from the virus are immune to new infection. (Screenshot)

Two things become obvious here quickly. First, the model has to have an accurate estimate of the number of people who are susceptible to the virus. And, second, the model assumes that once someone has had the virus and recovers, they are immune from new infection.

But what if either of those is wrong?

Through Tuesday, Colorado has reported 10,447 confirmed cases of COVID-19. But the modeling team doesn’t really look at that number because it knows that testing is sporadic. Instead, it has reverse-engineered an estimate from the number of reported hospitalizations. Ryan on Monday put the total estimated coronavirus infections in Colorado around 65,000 to 75,000.

New studies in California throw that estimate into question. When researchers conducted a large-scale study of blood tests from a cross section of residents in Los Angeles County, they found that more than 4% have coronavirus antibodies — the telltale sign of an infection. That put the estimated number of infections in the county in the hundreds of thousands, as much as 50 times greater than the officially confirmed figure. A study in northern California also found more widespread distribution of antibodies than expected, though both studies have generated controversy.

If there has been a similar silent spread through Colorado, the number of susceptible people could be way lower, impacting the overall projections. Katie Colborn, a professor at the Colorado School of Public Health who is on the modeling team, said the team reviews new research all the time and, if the studies are reliable, uses them to update the model.

On the flip side, it’s not entirely clear that people who have recovered from the virus will maintain immunity to it. Most researchers agree that at least some immunity is likely. But, as months drag on, it’s possible that immunity could fade. And, if that happened enough, people would end up circling back into the pool of susceptible individuals.

“So we need to be humble and modest that we don’t know everything about it,” Dr. Anthony Fauci, the nation’s top infectious disease doctor, said at a recent press briefing.

One thing that’s clear, though, is that there is still a long time to go before this is all over.

During a call with reporters earlier this month, Dr. Eric France, CDPHE’s chief medical officer, said he expects 30% to 40% of Coloradans to be infected by the coronavirus before it is squashed months into the future. That’s potentially more than 2 million people — 30 times more than the state’s current estimate for how many have been infected thus far.

So, get comfortable in your house. You’re probably still going to be spending a lot of time there.

Staff writer Jesse Paul contributed to this report.

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