While this is a D.C.-focused post, there are some general issues about COVID-19 that can be gleaned from digging into how D.C. is doing regarding COVID-19 (and it never hurts to look at data!). The good news–very good news–is that, as of Sunday, D.C. had four straight days with no deaths from COVID-19, the longest stretch since mid-March. Hopefully, that trend continues.
The bad news is that D.C.’s prevalence is still too high. As I’ve discussed here, the two-week prevalence of COVID-19 cases (the number of new cases in a two-week period divided by the population of the area you’re interested in) is a reasonable estimate of prevalence, provided there is adequate testing*. For D.C., here’s the two week prevalence by ward and for the whole city:
Ward 1: 0.087%
Ward 2: 0.066%
Ward 3: 0.040%
Ward 4: 0.097%
Ward 5: 0.069%
Ward 6: 0.081%
Ward 7: 0.109%
Ward 8: 0.114%
You’ll note that only Ward 3 is below 0.05% percent, and no ward is at 0.01%, which is a low enough prevalence to allow moderately risky activity. Here’s what the two-week prevalence looks like over time–note that the estimates for pre-June data are probably much higher, based on the percent positive rates (likely two-fold or more, especially in March and April):
One thing you’ll note is that D.C. on the whole was doing better a couple of weeks ago. The other thing to note is that, compared to June 17, other than the really hard hit wards, which have declined, there hasn’t been much change. Ward 2 has seen an increase in prevalence.
We also can use the ‘German threshold’ of 0.05% prevalence over a week–this is the threshold at which Germany throws the emergency break for a given region:
A couple of weeks ago, the entire city, including each ward, was in the clear (if barely). Now the city has edged over the 0.05% threshold and Wards 4, 7, and 8–heavily Black wards–are over the threshold too. Again, this is when Germany starts smashing the big red emergency button, yet all I can detect is complacency.
D.C., which did an amazing job massively slashing prevalence probably from greater than one percent to 0.08% (as mentioned above, in the first figure, the high values should probably be doubled at the least), seems to have eased off. If we want to lower the prevalence such that it would be very unlikely for a school outbreak to occur, then we have to lower prevalence further, probably to 0.01%. Unfortunately, D.C. is trending in the wrong direction.
To return to national patterns, there’s a lot of this going around–we’re releasing too early and not finishing the job, in no small part because of economic considerations and the role of schools as daycare.
Clearly, Arizona and Texas won’t be ready in September, but, even if things level off in D.C., I don’t think we’re there yet either.
*This is also a statistic the European CDC uses, and, in the U.S., when I’m able to find data like surveys of non-COVID-19 patients to hospitals, seems to match up reasonably well.