Will it be the end of Stage 1 in Maryland?

Since May 14, 2020, Maryland is carefully reopening from an easy lock-down caused by coronavirus spreading thru the community (and all over the world). In this post, I’ll go through all the variables we have on the MD Health Department dashboard. But first, the official data comes from the MD dashboard and if you want scientific information about COVID-19, please consult the CDC website. If you are interested, you can read my previous posts on COVID-19 in Maryland from this page.

Since my previous post (May 21), tests were broadened in some drive-thru locations for anyone to be tested (5/19 actually) and new testing sites were opened (map of sites here) and we had the Memorial Day weekend (5/25). On May 28, Gov. Hogan mentioned that “hospitalizations, ICUs, and testing positivity rates are the key metrics in determining Maryland’s road to recovery”. On May 27, Gov. Hogan announced that further reopening were taking place (outdoor dining, some outdoor activities for kids allowed, …) but still within Stage 1 (I called it “Stage 1b”).

In terms of hospitalizations, the graph above shows the number of patients currently hospitalized (green line). Since beginning of May, hospitalizations decreased, especially thanks to the decrease of patients in acute care (red line). Patients in ICU (Intensive Care Unit) decreased much slowly. This is probably due the severity of these patients, making them stay for a long time and released from ICU at a slower rate than patients in other departments. And the graph also shows that Maryland never needed the additional hospital beds prepared for a worst scenario.

The third key metric the Governor is looking at is testing positivity rate. The chart above represents, on top, the total number of tests reported on the MD Health Department dashboard (adding positive and negative test results). We learned that the Governor is actually not looking at the same positivity rate than the one we can compute from the dashboard:

  • The dashboard report unique positive and negative tests. If someone was tested twice or more with the same result, it would have been reported only once. If the test result would change, it would have been reported once in each category.
  • The Governor is looking at all positive and negative tests. If someone was tested twice or more, independently of the result, all tests results would have been counted here.

This difference probably explain why we see a daily number lower than 10,000, despite 500,000+ tests received by Governor from South Korea. But we can’t really say in which direction this difference would drive the testing positivity rate. If more positive tests were under-counted (i.e. counted once instead of the several times they were performed/received), the Governor would have seen a higher positivity rate than on the dashboard. More likely, if more negative tests were under-counted (i.e. negative people tested several times, but counted once), the Governor would have seen a lower positivity rate than on the dashboard. This last option would explain why the Governor decided to go on Stage 1 sooner than expected by just watching the dashboard.

Technically, as a side note, the data for the testing positivity rate that the Governor is looking at is not publicly shared. There is just a PDF with graphs. This difference in what is reported may also explain why, since test broadening (5/19), there was 5 days of ups and downs after which the rate stayed at about 10%.

At the level of the State of Maryland, we are not yet looking at the full picture: the last element (that doesn’t seem to be part of the key metrics) is deaths. So far (since mid-March), there have been 2,390 deaths due to COVID-19 in Maryland with a majority of them occurring in congregated facilities (nursing homes, prisons, etc.). With an about-weekly pattern (see below), the daily number of confirmed deaths also seem to decrease (although much slower than hospitalizations or positivity rate).

But if things seem good at the State level, the decision to reopen Maryland came with the empowerment of Counties (the government level below State) to follow or not the reopening. As noted before, if most counties followed the State in Stage 1, some counties did not (some like Prince Georges and Montgomery even remained “closed”). There is no straightforward way to follow hospitalizations in counties (they are not reported on the MD dashboard). But we can follow deaths in counties in the graph below. There it is a bit surprising to see that counties that re-opened, the % of deaths compared to May 15 is actually increasing (i.e. more daily deaths in counties that re-opened) (see blue dots and average in the blue line). On the other hand, % of daily deaths seems to decrease in counties that partially reopened or remained closed. But one should also note the huge confidence intervals around these averages.

Finally, about counties, the situation is about to get messier: since yesterday, Anne Arundel, Baltimore City and Howard counties further allowed some outdoor activities; and starting June 1st, Montgomery and Prince George’s counties, initially closed, will also start to allow some outdoor activities.

So, will it be the end of Stage 1 in Maryland? I think so. Most metrics that are publicly available are pointing in the right direction and, provided there is no outbreak in “pneumonia” like in California, I could see a cautious switch to Stage 2 in the coming days. Gov. Hogan tweeted that he could see Stage 2 during the first week of June.

To be continued …

As usual, you’ll find other graphs on my page about COVID-19 in Maryland and the data, code and figures are on Github.

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