AZ Pandemic in Numbers for the Week Ending Jan 23
Here are the numbers for the previous week:
All these numbers look encouraging except the vaccinations. According to experts, 50%-80% of the population will need to be vaccinated before the pandemic can be brought under control. If we only vaccinate 1.58% of the population per week, it will take us between 6 and 11 months to reach those levels.
Are These Numbers Reliable?
Here are a couple of grains of salt to season this week's encouraging-looking numbers. First, something seems to be very messed up with Arizona's testing stats, and possibly their other numbers too.
Have a look at the following, a screenshot of positive test percent over the last 180 days from the ASU Biodesign Dashboard (data source is ADHS):
Back in the fall, daily percent positives (Xs) were staying pretty close to the seven-day average (maroon line). But right around Thanksgiving the numbers start to go haywire, with a drastic increase in variance. On January 3 they even report 140% positive tests! This is a sure sign that ADHS is not properly keeping track of the days on which the positives and negatives were reported.
I asked around about this, and was told that the numbers jumping around is probably caused by a combination of things. First, positive tests are reviewed for duplicates (e.g., to ensure that a lab and a hospital didn't report the same positive). But in some cases facilities report their negative cases while the positive cases are being reviewed, leading to a large dump of positive cases on some days.
This is insane! Why aren't they required to hold the negatives for a given day while the positives for the same day are being reviewed?
Second, the variance spiked around Thanksgiving, and ADHS is just like any other organization. People take time off around the holidays. This has possibly affected their ability to get things done in a timely way.
Third, people at ADHS are exhausted and frazzled. This is understandable given that they are having to handle all their normal tasks, plus deal with testing and vaccine distribution tasks thrown over the wall to them by the incompetent previous U.S. administration.
The last two reasons, at least, are understandable. Nonetheless this makes it very hard to be confident that numbers published by ADHS are reliable. New cases per 100K seven-day average and inpatient beds seem to have been trending down for the last two weeks, yet emergency room bed utilization by COVID-19 patients has remained fairly stable. Suddenly people going to the emergency room are less likely to be admitted, or be diagnosed with the disease?
Things are just not adding up. On the other hand, there is a trend of declining new cases nationwide that is similar to the decline in new cases in Arizona. So who knows what to believe?
Infections Likely Higher Than Testing Suggests
A report from healthdata.org estimates that 17% of American's have been infected, about 10% higher than the national positive testing rate would suggest. They put Arizona in the 15%-20% range. If this is right we are in in line with the national numbers. This is a little puzzling given that we've been dubbed the worst place in the world two different times now.
Yuma Featured, and Not in a Good Way
Over the course of the pandemic, the Yuma area has identified coronavirus cases at a higher rate than any other U.S. region. One out of every six residents has come down with the virus.
The article goes into the reasons why Yuma is being impacted, including receiving an inadequate vaccine allocation from the state, an influx of snowbirds, and a large migrant farmworker population.
One out of six, or 15%, of Yumans being infected that may sound like it's in line with the report for Arizona in previous subsection. But remember that the number in the Times article is based on reported infections. According to the healthdata.org analysis those official statistics are like under-reporting true cases by more than half.
Update 2/21/21
The data table was updated to
correct a calculation error in statewide new cases.
Image by Shutterbug75 from Pixabay
