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These 10 charts show why Colorado leaders decided to get tough on coronavirus vaccine mandates

The stagnation of COVID-19 vaccination rates, the delta variant’s surge and fears of a coming wave of deaths and hospitalizations all played a part

COVID-19 vaccines await injection at the UCHealth COVID-19 mass vaccination clinic in the Coors Field parking lot Jan. 30, 2021. (Pool photo by Andy Cross/The Denver Post)
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After months of delicate persuasion campaigns meant to win the hearts and rolled-up sleeves of Colorado’s coronavirus vaccine hesitant, state leaders have in the last week added new muscle to the fight against the virus.

Governments, health care organizations and businesses have announced vaccine mandates for employees. Even some who vowed not to require the COVID-19 vaccine for their workers — like Gov. Jared Polis — have toughened their approach. Polis on Friday announced that state employees who are not vaccinated will have to submit to twice-weekly coronavirus testing and other measures.

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What’s behind this sudden urgency on vaccines is a realization that, as an internal Centers for Disease Control and Prevention document put it, the war against coronavirus has changed. With the highly contagious delta variant of the virus running rampant across the state among the unvaccinated, what worked before isn’t enough now. So leaders are choosing to more actively use their authority to push vaccination rates upward.

“The silver bullet we need for full recovery is to ensure maximum vaccination,” Denver Mayor Michael Hancock said Monday in announcing an order requiring not only city employees to be vaccinated against COVID, but also hospital workers, teachers and others in the city.

Here are 10 charts that explain why leaders have chosen now to get tougher on stopping the pandemic — and why they believe vaccination is the answer.

Alarm bells are ringing again

It might be a little too early to tell, but it sure looks like Colorado is at the beginning of its fifth wave of coronavirus since March 2020. Yes, a fifth wave.

The average number of new cases per day is showing that all-too-familiar scary ski jump pattern.

The chart from the Colorado Department of Public Health and Environment shows a rolling 7-day average of the number of people who test positive for COVID-19 in the state each day. It is current as of Aug. 3, 2021. An up-to-date version can be found at covid19.colorado.gov/data. (Screenshot by John Ingold, The Colorado Sun)

But there are other signs as well.

One early-warning signal the state has is data from hospital emergency room visits. The state tracks the rate of people who show up with coronavirus or flu-like symptoms but who don’t test positive for the flu. The metric has accurately tracked with each of the state’s previous four waves of the virus, and it’s on the rise again.

The chart from the Colorado Department of Public Health and Environment shows data taken from visits to hospital emergency rooms in the state. The red line shows visits by people with flu or coronavirus-like symptoms who did not test positive for the flu. The chart is current as of Aug. 3, 2021. An up-to-date version can be found at covid19.colorado.gov/data. (Screenshot by John Ingold, The Colorado Sun)

Hospitalizations are also increasing. On Tuesday, there were 383 people with confirmed cases of COVID-19 hospitalized in Colorado. That’s about 75 more than were hospitalized with COVID-19 at this time last year.

The chart from the Colorado Department of Public Health and Environment shows the number of people with COVID-19 who are hospitalized in Colorado. It is current as of Aug. 3, 2021. An up-to-date version can be found at covid19.colorado.gov/data. (Screenshot by John Ingold, The Colorado Sun)

One number that hasn’t increased so far is deaths from coronavirus. But that’s only partly reassuring to health and government leaders. In previous waves, a rise in deaths always followed an increase in cases and hospitalizations.

Widespread vaccination of the state’s most vulnerable may disrupt that pattern a bit. But health leaders say it’s still reasonable to think more cases and hospitalizations will lead to more deaths, especially since those being admitted to the hospital are seriously ill.

In order to prevent more hospitalizations and deaths, the Colorado Department of Public Health and Environment on Tuesday night announced that workers, residents and visitors at nursing homes and other residential care facilities will again be required to wear masks, regardless of vaccination status.

And health leaders say they need to impose other measures, like vaccine mandates, now before there’s a wave of deaths that can’t be stopped.

“Would the preference be that I wait until mortality goes up?” Bob McDonald, the executive director of the Denver Department of Public Health and Environment, said Monday at a news conference announcing the city’s vaccine mandate. “We need to make sure we’re ahead of this.”

The chart from the Colorado Department of Public Health and Environment shows a rolling 7-day average of the number of people with COVID-19 who died in the state each day. It is current as of Aug. 3, 2021. An up-to-date version can be found at covid19.colorado.gov/data. (Screenshot by John Ingold, The Colorado Sun)

The unvaccinated are getting hit much worse

The new buzz phrase among the state’s leaders is that this has become “a pandemic of the unvaccinated.” On Monday, the state epidemiologist, Dr. Rachel Herlihy, presented data to back that up.

Since July 1, she said, 80% of documented COVID-19 cases, 87% of hospitalizations and 92% of deaths have involved unvaccinated or only partially vaccinated people, she said.

Yes, there have been breakthrough cases, she said. And, yes, it does appear that the delta variant is slightly better at slipping past the vaccines’ defenses.

But in the current surge, the state is seeing a daily rate of new infections in vaccinated people of about three per 100,000 people and a rate in unvaccinated people of 17 per 100,000 people.

This chart produced by the Colorado Department of Public Health and Environment shows the rates of new coronavirus cases among vaccinated and unvaccinated people. It was shown during a news conference with Gov. Jared Polis on Aug. 2, 2021. (Screenshot by John Ingold, The Colorado Sun)

But fewer people are getting vaccinated

The number of doses of vaccine being administered across the state has stagnated.

Last week, vaccine providers in Colorado administered about 50,000 doses. That’s also about what they administered in each of the previous three weeks. The last time the state administered so few doses in a week was in late-December, when only a small percentage of people in Colorado were eligible to get vaccinated.

The chart from the Colorado Department of Public Health and Environment shows the number of doses of coronavirus vaccine administered per week in the state. It is current as of Aug. 3, 2021. An up-to-date version can be found at covid19.colorado.gov/vaccine-data-dashboard. (Screenshot by John Ingold, The Colorado Sun)

There’s another way to tell that the vaccine campaign has leveled off: The number of unused doses of vaccine in Colorado has increased dramatically.

In the early days of the vaccination campaign, there were usually only a few hundred doses that went to waste per week. As of mid-July, that number had increased to more than 40,000 unused doses per week, according to figures provided by the Colorado Department of Public Health and Environment.

This is a sign of the hard, one-by-one work that is going into the campaign now, as a provider might puncture a 10-dose vial just to get the vaccine into one new arm — and then be forced to discard the remaining nine doses.

But there are signs that the rising case numbers — and also perhaps employer vaccine mandates — might have persuaded some to get vaccinated. The Weld County Health Department on Tuesday reported that it has seen a 20% increase in vaccination rates over the past several weeks.

“The desire to get a COVID-19 vaccine is increasing,” the department stated in a news release.

We have less control over the virus now

Researchers with the Colorado COVID-19 Modeling Group calculate an estimate they call “transmission control.” The metric captures both the infectiousness of the virus and all the control measures in place to stop it — like mask-wearing, for instance, or staying home. Higher numbers indicate better control.

In some ways, the group’s latest report, released Monday, is reassuring. Despite many people edging back toward their pre-pandemic normal lives, the state should have been able to maintain relatively high levels of transmission control.

The problem is that the delta variant is just wildly contagious. That internal CDC document leaked last week pegged the original strain of the coronavirus at roughly the level of contagiousness of the common cold. The delta variant, meanwhile, was estimated to be as much as four times more contagious — higher than smallpox and as contagious as chickenpox.

So when the Colorado modeling group takes into account the delta variant’s infectiousness, it produces a transmission control value that is lower than at any other time during the pandemic.

This chart, taken from a July 28, 2021, report by the Colorado COVID-19 Modeling Group, shows estimates for transmission control of the coronavirus over time. As the green line shows, the decline in control beginning in the spring of 2021 is due largely to more infectious variants of the virus. (Screenshot by John Ingold, The Colorado Sun)

Health leaders are worried about the fall

One of the big concerns that health leaders have is the timing of this surge. It’s especially worrying to them that it’s happening now, in the heat of summer.

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In their view, respiratory diseases like COVID-19 typically thrive in the colder air of winter — that’s when people head back indoors, that’s when kids return to school, that’s when viruses may be able to survive longer outside the body. So, if the current wave rolls into the fall, health officials are concerned it will lead to a supercharged spike.

That’s why Denver set the deadlines for its vaccine mandate by the end of September.

Projections from the modeling group show that the surge will likely get worse — but how worse is unknown.

If transmission control stays at its current level, the modeling team estimates that Colorado will see a small peak in hospitalizations in October or November. And, if vaccination rates improve, the peak won’t materialize at all.

This chart, taken from a July 28, 2021, report by the Colorado COVID-19 Modeling Group, shows a prediction for how hospitalizations due to the coronavirus would change under a scenario where transmission control of the virus remains at current levels. The blue line shows a projection based on current vaccination rates. The other lines show projections based on various increases in vaccination rates. (Screenshot by John Ingold, The Colorado Sun)

But if transmission control declines further and the vaccination rate doesn’t improve, the modeling team projects that Colorado could see a spike in hospitalizations rivaling what hit the state last winter — which led to the deadliest months in state history.

This chart, taken from a July 28, 2021, report by the Colorado COVID-19 Modeling Group, shows a prediction for how hospitalizations due to the coronavirus would change under a scenario where transmission control of the virus drops. The blue line shows a projection based on current vaccination rates. The other lines show projections based on various increases in vaccination rates. (Screenshot by John Ingold, The Colorado Sun)

We still have a long way to go

The good news: An estimated 63% of the state’s population is now immune to the coronavirus, either through vaccination or having been previously infected, according to the modeling group. (This figure includes kids who are not yet eligible to be vaccinated. Nearly 65% of those old enough to be eligible for vaccination in Colorado are fully immunized.)

This chart, taken from a July 28, 2021, report by the Colorado COVID-19 Modeling Group, shows an estimate of the number of people who are immune to COVID-19 in Colorado. The top line shows immunity acquired through either vaccination or infection. The bottom line shows immunity from just vaccination. (Screenshot by John Ingold, The Colorado Sun)

The bad news: In the era of the delta variant, that’s not nearly enough.

The quest for herd immunity — the level at which there aren’t enough people susceptible to the virus for an epidemic to be sustained — is a longer one now. For much of the pandemic, experts had been estimating that it would take at least 70% immunity to achieve herd immunity against the coronavirus.

But the herd immunity threshold is calculated based on a virus’s infectiousness. Because the delta variant is so much more contagious, we likely won’t reach herd immunity until at least 80% of the population is immune and maybe not until nearly 90% of the population is.

This shows how much farther the state has to go in ending the pandemic. And it shows why government and health leaders believe that getting there through vaccination will be a lot less painful than getting there through infections.


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