Why Is Colorado Doing So Much Better With COVID-19 Than Arizona?

 

Last night Colorado Governor Jared Polis appeared on the PBS Newshour talking about pandemic-related matters.  The interviewer noted that Colorado had a rough November but now all the numbers are going in the right direction.  

In Arizona we had a relatively good November, but then all the numbers started going in the wrong direction—really wrong.  Arizona regained the dubious title it held in July as the worst place in the world for COVID-19.  This made me wonder how the two states compare overall from December to now.

So I fired up the CDC Socrata API and ran some queries.  Here are new cases and new deaths per 100K people* seven-day moving average (AZ in blue and CO in orange throughout):

As of last weekend, Arizona's case rate is over three times higher, and its death rate was over five times higher than Colorado's!  

The question is, why?  Polis attributes it to good behavior of his constituents: "Well, Coloradans are doing the right thing. That means wearing the mask around others. It means avoiding socializing with people outside of their home and trying to keep a distance where they can."

I'm not sure I buy this as a differentiator of the two states. It's no secret that conservatives have been more resistant to mitigation measures than liberals.  But Colorado is fairly similar to Arizona, politically speaking. Both states have close to the same number of Democrats, Arizona has about 8% more Republicans, Colorado has about 10% more "other."  Those don't seem like big enough differences to explain the huge gap in pandemic numbers.  A friend in Colorado confirms that they have their share of mitigation resistance there.

Let's consider other factors that might make the difference.  Once strong possibility is that the Polis administration is simply doing a better job of managing the pandemic than the Ducey administration.  For one thing, Colorado has a formal system called the Dial Framework that automatically invokes statewide mitigation measures when objective metrics like testing, positive cases, and hospitalization cross certain thresholds.

In Arizona, the Ducey administration has taken an overall ad hoc and lazes faire approach to mitigation, leaving the matter to counties and municipalities. An exception was when governor infamously issued an order last spring prohibiting those entities from establishing mask ordinances, only to reverse course in June as we became the worst place in the world for COVID-19 (the first time). He still refuses to issue a statewide mask mandate. The governor issued an executive order on June 29 prohibiting large gatherings and closing restaurants, bars, theaters, gyms, etc., but allowed them to reopen at the end of August. So the Arizona state government is not being nearly as aggressive as Colorado's in mitigating the pandemic.  

Colorado is also doing a much better job than Arizona of getting its citizens vaccinated.  Here is a chart based on data from the CDC and adjusted for population:

Colorado has distributed about 17% more doses and has delivered about 75% more doses than Arizona.

Finally, an undoubtedly big factor is the difference in the Native American population in the two states.  Arizona has the third-largest Native American population in the country, with 399,151 people making up 5.39% of the state's residents.  Colorado has 120,638 people making up 2.07% of its residents.  

This difference is important because Native Americans, especially those living on reservations, have been getting hammered by COVID-19.  A recent CDC report concluded that these foks have a COVID-19 mortality rate 1.8 times higher than people of European ancestry. 

Navajo and Apache counties, which include portions of the Navajo, Hopi, and Apache reservations, routinely top the chart for new cases.  At one point earlier this month, Greenlee County, which includes a portion of the San Carlos Apache reservation, reported 249 cases per 100K on a seven-day average, the largest number I've seen anywhere.

Public health researchers attribute the high COVID-19 incidence on reservations to factors including lack of complete indoor plumbing, lack of access to potable water, household overcrowding, and lack of health information in native languages.  I have also heard tribal leaders complain of lack of access to hospitals and other medical care.

So it looks like our neighbors to the northeast are doing better because of a mix of things: (perhaps) slightly better adherence to mitigations, a much more competent government response, and a difference in the population makeup.

*Calculations use populations of 7,424,805 for AZ and 5,826,180 for CO.