Good news about coronavirus across the U.S.; Why Are Coronavirus Cases Decreasing – Restrictions or Herd Immunity?; Europe update; Germany study; The Odds of Catching COVID on a Flight Are Slim
I continue to closely follow the pandemic, sending lengthy e-mails to my coronavirus e-mail list roughly twice a week (if you'd like to receive it, simply send a blank e-mail to: cv-subscribe@mailer.kasecapital.com). Below are excerpts from the e-mail I sent yesterday:
1) The news continues to be good from across the U.S. – cases, hospitalizations, and deaths are all trending downward. It's even possible that our daily new cases may fall below Europe's if current trends continue, as this chart shows:
This chart shows the number of hospitalized Americans:
And this one shows deaths per day:
Cases among the elderly also remain low:
2) There are two competing theories for why the virus is tapering off. The first is captured by this New York Times article: Why Are Coronavirus Cases Decreasing? Experts Say Restrictions Are Working. Excerpt:
Of the states that are driving the decrease, all have at least some local mask mandates, and most have paused or reversed statewide reopening policies, again closing bars, gyms and theaters.
The article concludes:
The flattening – albeit still high – numbers are a positive sign, experts say. But they caution that resurgences can and will happen again as schools reopen and hurricane season begins.
"We basically have 50 laboratory experiments going on right now, and every state has a slightly different policy approach," Dr. Gerald said. "If we get complacent, this thing could get out of control again. And we'll have even less safety margin to manage it because we're starting from a higher place."
3) Adam Patinkin rejects this theory: "All you have to do is overlay Google mobility data and you'd quickly realize this entire article is bunk."
Responding to this article, Herd Immunity For COVID-19 Is Still a Terrible Idea and this similar thread by Joel Miller, he writes:
The article and the thread make numerous logical errors. The authors are acting as if "herd immunity" is not inevitable (it is) and hand-waving the overwhelming data that we have reached disease break point in most of the world.
Of course the level of disease break point can vary widely in different populations based on social graphs, prior immunity (see the German study showing 81% of Germans have some pre-existing cross-resistance from T-Cells!), etc.
Finally, point No. 1 about social distancing having little impact on the outcome of the models is exactly the same conclusion we reached back in March. It is not a surprise at all. And if you think about it mathematically, it makes a ton of sense. If you reduce the number of interactions you have per day from 100 to 50, or to 30, because of how power laws work, the effect ends up being very small (100x100x100x100x100 is a very, very big number and 30x30x30x30x30 is also a very, very big number). You'd literally have to reduce your number of interactions to 2, or 1, or 0, to have a meaningful impact on the model. That is just not going to happen for most people.
The benefit of social distancing (to me) has nothing to do with reducing the disease break point or effective HIT. Nothing at all. Instead, it has to do with reducing initial viral loads. If we have most of our interactions outside, or moderately social distanced, I'd bet health outcomes end up better because the initial viral load goes down. But it won't reduce the number of people who end up being infected. The math just doesn't work that way.
4) Here are Adam's thoughts about what's happening in Europe:
We are seeing the same patterns in Europe that we are seeing in the U.S. The data is all very consistent (and encouraging!).
First, the rise in positive tests in Europe is closely correlated to a rise in overall testing in Europe. Looking solely at absolute positive test numbers is misleading without considering them in the context of higher overall testing levels.
Second, local areas that did not experience a first wave are seeing their wave now (Catalonia, Manchester, etc.).
Third, fatality levels remain extremely low in Europe and have not seen a commensurate surge as more cases are in young people, are asymptomatic (and being identified via more testing), and due to better treatments. (For more on this, see this Bloomberg article: Europe's Virus Surge Is Looking Less Deadly Than Initial Wave)
Look, for example, at England which reported just one COVID-19 death yesterday in a country of 70 million people:
This is akin to the FACT states like Florida that will likely have a small fraction of the fatalities per population as NY/NJ, etc., due to better policies, better treatments, and other factors that together help lower the IFR.
The vast majority of Europe has already reached its disease break point. The COVID-19 public health crisis is nearly over. But we will continue to see localized outbreaks (that are quickly contained) until the entire population reaches its disease break point, not just the major population centers and/or where major first waves occurred. It's the process of burning out. This is exactly what epidemiology 101 tells us should happen.
The narrative in the U.K. is changing:
5) Dr. Kevin Maki, President and Chief Scientist, Midwest Biomedical Research and Adjunct Professor, Indiana University School of Public Health, writes:
This study is big news and very likely is at least part of the reason that Germany has had a less severe epidemic of COVID-19 compared to many other EU countries. Here's an excerpt from the abstract:
Cross-reactive SARS-CoV-2 T-cell epitopes revealed preexisting T-cell responses in 81% of unexposed individuals, and validation of similarity to common cold human coronaviruses provided a functional basis for postulated heterologous immunity in SARS-CoV-2infection. Intensity of T-cell responses and recognition rate of T-cell epitopes was significantly higher in the convalescent donors compared to unexposed individuals, suggesting that not only expansion, but also diversity spread of SARS-CoV-2 T-cell responses occur upon active infection.
The paper identifies epitopes (part of an antigen molecule recognized by an antibody or T-cell) to which CD4 and CD8 cells respond. However, the bigger finding is that so many people had pre-existing responsiveness despite never having been infected with SARS-CoV-2. Those who had been infected with SARS-CoV-2 had higher intensity of response and higher recognition rates, suggesting that there is expansion of the number of epitopes recognized after SARS-CoV-2 infection. Thus, some degree of T-cell response is expected in a substantial fraction of the population who have had prior common cold coronavirus infection (presumably), which may shift the severity curve to the left but not entirely prevent infection or symptoms. T-cell response intensity and number of epitopes recognized appeared to be enhanced after SARS-CoV-2 infection.
Germany has been toward the bottom of countries in Europe regarding cases and deaths, with one-fifth to one-sixth the values per million observed in the U.S. In the U.S., 20%-60% of samples have shown pre-existing T-cell responsiveness. A higher prevalence of prior common cold coronavirus infection could be an important determinant of that difference.
6) This is good to see: The Odds of Catching COVID on a Flight Are Slim. Excerpt:
If you decide to fly, the odds that you will pick up COVID-19 are low, according to one expert analysis. Despite the known dangers of crowded, enclosed spaces, planes have not been the sites of so-called superspreading events, at least so far.
That's not to say flying is perfectly safe – safety is relative and subjective. But as restrictions continue to change, the only way to move forward through this long pandemic is to start thinking in terms of risk-benefit ratios. Very little is without risk, but perhaps some risks – such as flying – are small enough to warrant taking.
Arnold Barnett, a professor of management science at the Massachusetts Institute of Technology, has been trying to quantify the odds of catching COVID-19 from flying. He's factored in a bunch of variables, including the odds of being seated near someone in the infectious stage of the disease, and the odds that the protection of masks (now required on most flights) will fail. He's accounted for the way air is constantly renewed in airplane cabins, which experts say makes it very unlikely you'll contract the disease from people who aren't in your immediate vicinity – your row, or, to a lesser extent, the person across the aisle, the people ahead of you or the people behind you.
What Barnett came up with was that we have about a 1/4300 chance of getting COVID-19 on a full 2-hour flight – that is, about 1 in 4300 passengers will pick up the virus, on average. The odds of getting the virus are about half that, 1/7700, if airlines leave the middle seat empty. He's posted his results as a not-yet-peer-reviewed preprint.
The odds of dying of a case contracted in flight, he found, are even lower – between 1 in 400,000 and 1 in 600,000 – depending on your age and other risk factors. To put that in perspective, those odds are comparable to the average risk of getting a fatal case in a typical two hours on the ground.
The numbers all sound low enough, though Barnett says they are still high compared to the 1 in 34 million odds your flight will end in a deadly crash. He told me he wouldn't fly right now because his age, 72, puts him at higher risk than the average American, and he says you have to consider the risk of adding to the problem by getting the virus and unknowingly passing it on to others.
Best regards,
Whitney