The COVID Digest, 22Jan2022

Here comes the death surge

Today’s newsletter covers the following topics:

• The myth of decoupling

• With cases and hospitalizations, deaths usually follow

• COVID-19 trends in kids

The Myth of Decoupling

First, let’s take a look at what’s happening nationally. Since the start of the Omicron surge there has been this talking point that because cases were “mild” that we were going to see this “decoupling” of cases and hospitalizations and deaths, allegedly because of high vaccination rates in some areas and high seroprevalence (from past infection). But this really hasn’t come to pass if we look at things from a national perspective. It initially looked that way when the majority of the surge was due to Delta, but once Omicron took over, that decoupling observation seemed to disappear.

Consider the regional trends for cases and hospitalizations. In early December 2021, we see that case rates are equal between the Northeast (blue) and the Midwest (purple). Then consider the graph below (follow the blue arrows) that looks at regional trends for hospital admissions. Here we do see a decoupling. Case rates were about the same and rising together between these two regions but there was a significant change in hospital admission rates between these two regions. This is when Delta was still the predominant variant of SARS-CoV-2 that was circulating.

Then look at what happened in late December - early January 2022. The case rates are rising for both regions and their hospital admissions rates are rising equally too. So no more gap. In fact, the gap we do see is not what we might have expected to see - hospital admission rates are actually higher for the northeast than for the midwest. There may be a couple things that contribute to this - (1) it’s possible there is more hospital capacity in the northeast than in the midwest, so they can admit more patients before reaching saturation. (2) The greater population density of the northeast produces additional opportunities for disease to spread. Yes, the graphs adjust for population, but on the front end where infections happen there are more opportunities. (3) It’s possible that test capacity is better in the northeast than the midwest, so that could account for the difference in case rates.

So for all the talk that this wave would somehow be better because there was a “milder” variant, this surge has resulted in the highest case rates ever recorded and the highest hospital admission rates ever recorded.

The other myth that I’ve heard circulating is that “well, maybe this surge is the one that finally tips us over into herd immunity.” Just remember that there’s a safer way to get to something approaching herd immunity - through vaccination. When we willingly infect our population, we are effectively feeding people into the chipper of death and destruction that COVID-19 can cause. You have to wonder why this is the path America has chosen.

I have previously highlighted some of the tremendous tools generated by Drs. Stephen Beckett and Joshua Weitz at Georgia Tech for estimating the risk that someone is COVID-19 positive at an event of given size in a given county. But another tool they’ve developed is an estimate of population level immunity based on infection rates and vaccination rates. For these graphs, the y-axis is showing how much of the population is fully vaccinated. The x-axis is showing how much of the population has been infected. A state’s position on the graph is where those two data points intersect. If we take a middle of the road ascertainment bias of 4 (ascertainment bias - estimates how much of circulating disease we’re missing with asymptomatic cases and testing insufficiency) and look at the fully vaccinated population, then the population level immunity for the northeast is shown below. Note: the regions are determined by the US Census Bureau.

Rhode Island is above 90% and all the others are above 80%. Early estimates for herd immunity (pre-Delta) were 75-80% of the population. After Delta which was much more transmissible, the herd immunity estimates were 90-95%. And yet, Rhode Island has the highest case rate in the nation according to the 19Jan2022 HHS Community Profile Report.

Since we’ve been comparing the northeast and the midwest, let’s look at the midwestern states. About half of them are above 80% and half are below that threshold. So it has even farther to go.

I bring this up because we need to not assume that the talk of “endemic” means that the pandemic is “ending.” Endemic means the disease is naturally occurring below epidemic levels. This would be as in, no spikes or surges. As long as we keep experiencing surges across multiple continents, the pandemic remains a pandemic. And one of the ways we can achieve “endemic” status is to get case rates low enough is to reach herd immunity. But with SARS-CoV-2 causing repeat infections and breakthrough infections for those who are vaccinated, that may not be the most reliable way to bring this pandemic to heel either. Instead, we may need to make the infrastructure improvements that were recommended a long time ago to improve indoor air quality and cut down on transmission. Because having hospitals go to crisis standards of care and national guard troops babysitting classrooms because of widespread teacher illnesses is not “living with the virus.” This indifference to the reality and the suffering of others is feeding people to the chipper, and not even getting us closer to the goal.