COVID Spring??

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As a reminder, last year we saw COVID cases peak in early to mid January and then dropped until mid March when we saw a 4-5 week wave of new cases. It was mainly in a few states – most notably Michigan and the peak never got close to the winter peak. Starting in late April, cases really started to drop hitting a minimum in mid June before the Sun Belt summer wave started.

At this point, there is not sufficient evidence to say that pattern is going to repeat but there are some interesting things in the data this week so it would not shock me to start to see cases tick back up again.

For the week ending on March 13, there were 236,049 newly reported cases. This was down about 18% from the week before. Still a big drop but much smaller than the previous weeks but we expect that as we get closer to a low. This is the lowest number of newly reported cases in a week since the first week in July. At this time in 2021, we had 378,891 newly reported cases so we are below last year’s total.

For the week, the percentage of positive results was 4.4% which is unchanged from last week. In what may or may not be a coincidence, back in March of 2021, we bottomed out at 4.4% before cases started to rise again. We’ll see in a couple of weeks whether that was significant or not.

Another interesting observation is that we had five states and the DC where cases jumped last week. And several of these were big jumps. The overall numbers remain low and a single week does not make a trend or pattern. This could simply be a backlog of unreported cases. Still it is just another thing that makes me wonder if we aren’t going to see cases start to turn back up.

Here is the graph showing cases per million vs the weekly percentage change. Montana saw the biggest drop during the week leaving Idaho and Alaska as the outliers in terms of cases.

I think it might be useful to show the time series graphs just to put the increases in perspective and to show where the current numbers are relative to the history of COVID.

We’ll start in the Northeast. If you squint hard enough, you might see the dark blue line that is Pennsylvania moving up last week but the actual number of cases doesn’t stand out compared to the rest of the states in this region.

The we move down the coast a bit. Again, it is very hard to see but the dark blue line that is DC did tick up last week but the actual number of cases is basically the same as the other states. One thing about percentage increases is that it is easier to have a big percentage increase when the actual starting number is smaller.

Here is the Midwest and, right now, it doesn’t look like Michigan is going to have a repeat of last year. All three of these graphs do show that peaks this wave were much higher than the previous fall/winter. But last year, we had a slow and jagged decline while, this year, it has fallen just as fast as it rose.

Like the Midwest above, all the states here saw cases drop. West Virginia remains higher than the rest and, for perspective, had the 3rd highest total of cases per million last week. Just a statement of how low the overall numbers actually are when looking at the history of COVID.

Into the South where all the states also saw a decline and you can see the actual numbers are at very low levels.

In the upper plains, we have the same basic pattern but you can see the curves starting to flatten out which we expect as we get close to a low. This is why you can’t continue to sustain big percentage drops. Given the low numbers, it would not be a shock to see some of these states bounce up last week. At some point you get into false positive range where all you are really seeing is some random bounces that could be related to testing frequency.

Now we get to two of the states (Arkansas and Texas) where cases increased last week. Arkansas is easier to spot and it actually had the 4th highest total number of cases per million last week. Relative to the history, it remains low but it needs to be watched. Texas is harder to see.

Into the Rockies, where you can see how much of a decrease we saw in Montana and that Idaho remains relatively high even as cases are coming down. You can see the dark blue of Colorado in the last week as cases did go up there last week. Colorado was one of the places where we saw an April rise last year but we can’t really make anything out of a single data point so we need to see what happens over the next couple of weeks.

Arizona is the last state that saw an increase and you can see that if you look hard enough. Like most of the other states that saw an increase, it does not yet stand out from the rest of the states in the region. With all of these graphs, you can look at flat portions of the curves and see random weekly bounces which is why we don’t draw any conclusions from a single point.

And the last group of states where Alaska, like Idaho, shows a relatively high number of cases but continues to see cases drop.

Overall, the numbers remain positive. Cases continue to drop and continue to approach the lows of last summer. We just need to monitor and see if we see the same pattern we saw in late March and April of last year. Right now, there is not evidence to say that we will – just some hints in the data that need to be watched.

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