In this post, we'll look at the data they shared that drove that decision and some other details that might suggest a different approach. Before I do that, I want to acknowledge that many people are anxious to get our economy up and running again and many are frustrated with Governor Cooper. I think its important to recognize that he is in a very difficult position-- more difficult than I think he ever dreamed of experiencing when he was sworn in. He has spent most of his life in politics and history will pretty much judge him by what he does this year. He's having to make decisions without the information you would want to feel certain you are choosing the right path. Whether I agree with him or not, I trust he believes what he is doing is protecting the people and hospitals in our state.
The Criteria and Data
Governor Cooper looked to Secretary of Health and Human Services Dr. Mandy Cohen to lay out the criteria and data they are looking at. Dr. Cohen used similar criteria to the ones from the White House that I described in my earlier post: COVID Symptoms from our Flu Surveillance system, 14 Day trends in new cases and positive test %ages, and the potential load on hospitals.
For the first criteria was about hospital visits with flu-like symptoms that would indicate potential COVID cases.
The Red line has been trending down for more than 14 days, so the Dr. Cohen confirmed that this criteria had been met.
The second criteria is about the number of new cases per day. We're looking for that number to show a 2 week decline. Here is their graph from the NCDHHS dashboard site:
As in my analysis, this trend line is curving up. I think some additional context would help, though. Here is our trendline of new cases compared to Georgia, Florida, and Michigan (Ga and Mi are the closest to us in population. Fla has twice our population).
While we are slightly curving up, our curve has always been much flatter than our peers so even fairly small changes in counts - about 100 cases a day over the 14 days -- looks like s significant increase when other states are still far from achieving our daily case rate.
The third Criteria is about the trend in positive testing. Here, the NC DHHS offers this chart:
Although the criteria is for 14 days, they plot the trend line across 21 days to create the dashed 7 day average line. Also they appear to be using different data on testing from that logged by the COVID tracking project, which pulls data several times a day from the DHHS site -- I've been using the COVID tracking projects' data throughout my research. Here's what my graph looks like:
The lighter lines are the calculated trend lines. The blue line at 10% is trending slightly down over 14 days, but the red trend line is slanted upwards. Because the positive rate was much lower 3 weeks ago, it is driving the rolling average upwards. It's also a good idea to look at the rate of testing against the positive testing rates:
Here the positive test rate is the blue line while the number of tests is the red line. You can see we had a major dip in test rates mid-month that we've since recovered from. When the number of daily tests drop, tests are normally targeted to the most likely cases so the % positive also goes up, as you see it did here from April 17 to the 20th. That means that the bump in positive testing that is driving DHHS' trendline up probably has nothing to do with the actual COVID cases but is just the effect of having a shortfall in cases. Also, the fact that our positive test rate has gone down as we've nearly doubled the number of daily tests in the past week should be a very promising sign.
The White House recommendation is that a state should be seeing either drop in new cases or in positive testing over 14 days. Even though NC does not meet the criteria for new cases, it would still pass if there was a decrease in positive testing rates, which depends on whether you use 21 days for the 14 day trend, and how you interpret the effect of the dip in tests.
Before moving the the next criteria, here's a graph of our comparison states and their positive test rates for context:
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North Carolina has had a consistently relatively low positive test rate throughout the COVID pandemic.
The next criteria is the ability to treat all patients without crisis care. The White House didn't define a particular measurement to gauge this ability. NC DHHS provides this graph of current hospitalizations in NC.
This is current hospitalizations, so as people recover and are discharged, the number will grow and shrink. Dr. Cohen pointed out how this line is also trending upwards, indicating we have not crested the curve. While this a fair read, but should be looked at alongside DHHS' report on hospital occupancy:
This shows that more than 1/3 of hospital beds in the state are empty. The 6836 beds in this graph is almost 15 times the number currently being used by COVID patients. Even if we suddenly saw a 5x surge in new COVID hospitalizations (and the line looks like its flattening) we would still not come close to overwhelming hospitals. If you follow the DHHS link above, you'll see that almost 4 out of 5 ventilators are also currently unused.
Again for context, here is the hospitalization trend in other states:
Florida and Georgia report cumulative hospitalizations, not current ones. Current counts are probably about half that shown here, but we are again much lower than comparable states.
The final criteria from the Governor is for adequate testing and PPE to meet North Carolina demands. Testing was behind national average but is now catching up. DHHS provides an interesting look at PPE needs and supplies for the state. I don't have a way to analyze this data, but given Burlington NC is the headquarters of Labcorp, one of the two private companies doing most of the COVID testing in the country and that NC's long history of textiles should give it relative advantages in getting PPE and tests for the state. For example, the Nonwovens institute at NC State is producing enough material to make 500,000 masks a day.
So after looking at the 5 criteria, only the first one from the Flu surveillance data was judged positive enough to pass:
As I said at the beginning, this is a difficult job and I trust Dr. Cohen is using her best judgement and the counsel of the best people she can find before making her recommendations. I believe honest people can disagree with them, but I respect her efforts and leadership.
The differences come from how you look at the graphs. Governor Cooper sees lines sloping up and is insisting on more time to slow the virus. Others may look at the graphs and data of NC compared to other states and conclude that we have already benefited from one of the slowest COVID growths in the country. In addition to the graphs I showed above, North Carolina has one of the lowest case rates and death rates in the country (37th and 39th respectively). Those doing better (besides TX) are less than half our size.
Because we've had a relatively low COVID curve to begin with, I believe our leaders should take small upward growth trends in context. Knox county Tennessee recently released a plan for opening their community. They also have had a very flat curve and made this observation:
An Increase in Cases is Anticipated Due to Initial Low Case Counts Through the joint effort of citizens in “flattening the curve,” the number of active COVID-19 cases has stayed far below the capacity of the health care system. This has provided the region with time to increase supplies of personal protective equipment (PPE), hospital surge capacity, testing capacity and the ability to surge contact tracing should it be needed and appropriate. As we locally advance through the phases, we anticipate an increase in active cases at each phase due to the low number of initial active cases. The focus of the benchmarks outlined in this document is on assessing the local ability to manage an increase in cases while preventing the unobstructed growth of transmission. Our low initial active case counts will likely mean we will not obtain a downward trend throughout the phases of the reopening process. Our community demonstrated success in flattening the curve before it truly started. Due to this initial success, future phases will result in increased numbers of active case counts. This alone is not a reason to revert to a previous phase or not advance to the next phase. This perspective could also apply to much of North Carolina. |
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