College is Back in Session. Did COVID Come Back With it?

Interesting data from the first week or so back at schools. University of Arizona had about 126 cases reported today while the entire rest of the county had around 30. Test positivity (a bad metric the way most government groups are trying to use it) has been about 2.5% at U of A since 7/31 until today where it jumped to 8.2%. Its hard to make much of a judgement from this as I don’t have any of the data between 7/31 and today, but that might be surprising. It does appear to be a large jump in tests from the average since 7/31, which might indicate there are more people feeling sick enough to get tested. I can’t tell much more because U of A’s data is kind of sparse and I can’t find numbers to indicate how many students are on campus right now. ASU, however, gives us a better wealth of data about their cases…

Here’s from the Arizona State University COVID page.

Takeaways from this info are as follows:

  1. First off, we don’t have good numbers from ASU on how many tests were given to arrive at the numbers listed above.
  2. Cases for ASU faculty and staff appear low compared to their likely demographic in the rest of the state. The number listed is 0.2%, but it isn’t clear if that’s a cumulative count or an instantaneous count of active cases. Even if it is the count of Active Cases and these staff are in quarantine, that is still far lower than the instantaneous count of the students Active Cases (see below, it’s 3.4%). The demographics that ASU employees are most likely to be in ranges from 20 to 64, which represents 3 demographic categories the state has been collecting case data on. All three of these are experiencing something on the order of 3.6% cumulative infection rates (or 36 out of 1000 as my chart below shows), so we would expect their current outbreak rates to be similar. There may be a data collection divergence between ASU collection and the State of Arizona collection (perhaps some faculty and staff tested positive over the summer at a CVS but didn’t tell their employer?). However, this is still a fairly big gap. Does it mean that university employees are less likely to get COVID than their same-age counterparts outside the university? What about their potential exposure to sick students? More to follow, but this does present some interesting questions.
  3. The 1.3% positivity across all 74,500 non-online students is probably a case where the denominator is artificially large. How many of these students left campus and have been sheltering at home? I don’t think this number is relevant.
  4. The more interesting indicator is the 336 positive students out of 9662 living on campus at Tempe. It’s unclear what the time period is that ASU has been collecting this, but the fact that they are apparently currently in isolation sounds like they are Active Cases, not cumulative cases. If true, this is a very high rate of Active infection for the Tempe campus (3.4%) and is about equal to the infection rate their age demographic has experienced cumulatively in the state since the start of the outbreak. This would be a big jump (it would account for 1/2 of the cases in the County on 9/2) and it appears that we can see it on the Maricopa County case chart.
  5. There are 32 cases out of 1195 in the ASU Downtown and ASU west campuses. Again, well have to assume that these are active cases since they’re referenced as being “in isolation”. Therefore, 2.6% of the students at these two campuses are currently sick with COVID-19. Compare to 3.4% from Tempe and 0.2% in the faculty and staff.
  6. Finally, and my favorite stat here is that there are 0 cases out of 771 students at the ASU Polytech campus. That of course is 0%. What do we take from this? Nerds are more careful? They wash their hands more? Or maybe there’s just not much partying going on at this campus (it has various government agencies sharing the campus along with other technical education programs).
as of 9/2/20, the cumulative count of cases by age group measured as a count out of 1000 people in that age group.
cumulative total case count for Maricopa County. Note the measurable increase in slope on 9/2. Perhaps this is due to the cases on the ASU campus.

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