CFR, R0, and Death from Covid-19 (6 Pics)

Okay everyone, listen up. We're going to talk about Covid-19 and talk SCIENCE! There seems to be a lot of confusion about what Case Fatality Rate (CFR) actually means. But are we going to take some random person on the internet's word for it? NO! We're going to talk papers, links, and go through it. Don't believe me, believe the science! (TLDR at end) I am also including dates on papers because this the science is still evolving on the issue. It is important to remember that science reflects DATA. But we're solving this issue in situ (as it is happening) so data is still being gathered. We'll have a much clearer position when analysis is post hoc (after). That'll be in a few years.  Note: We're just getting the facts straight here. Please keep social distancing. But there is a position between total panic and absolute nonchalance.

Fauci paper (Feb 28 2020): https://www.nejm.org/doi/full/10.1056/nejme2002387 So there's a few things here. We notice that Fauci's team reports a CFR of 2% and that another team, Guan et al, reports 1.4%. Here they say that it may even be less than 1%. Some people confuse the next line to think that this is just another flu, spoiler alert, it isn't. But, this also isn't SARS or MERS. Note: 1% would be 10x as bad as the flu, and even if it is as bad as the flu that means we have two flues at the same time, which isn't good either (it's worse than that though). So why could it be less than 1% if Fauci measured 2%? Because this was late February and there wasn't much testing. You calculate CFR by taking the total number of deaths and dividing by the total number of effected. So let's look at that.

Looking at Italy, 23227/175925 = 0.132. So Italy has a CFR of 13.2% right?! THIS IS WORSE THAN SARS! We're nowhere near that 2% Fauci thought was the upper bound, this shit is real! NO! This is where it gets tricky. As we all know, testing is still bad and not being done. Italy was reporting that 50-75% of people were asymptomatic, meaning they didn't show signs of symptoms at all. So what can we do to find the real number? Well, antibody testing helps!

Stanford (April 11th 2020): https://www.medrxiv.org/content/10.1101/2020.04.14.20062463v1 Here we see Bendavid et al say that there are 85 times the amount of people that have been infected with Covid than official numbers say. This is weird, right? Not really. Official numbers are those of __confirmed__ cases. That is, you went in, got tested. But if you got Covid and never had any symptoms or they were mild enough that you didn't get tested, you wouldn't show up on this counter even though you were infected. This includes my PhD advisor who had a fever for 5 days. Did they have Covid? Who knows, they couldn't get tested. So if we don't have enough testing, what do we do? In Bendavid et al, they take a sample population, in this case in Santa Clara County, and extrapolate the data from there. They tested for antibodies to more specifically find people that were asymptomatic. This suggests that CFR is lower than the initial 2% that Fauci reported, and matches his suspicions that it is below 1%. But that's one paper and we probably shouldn't just trust Stanford School of Medicine on this one. Let's see if their result makes sense with other work.

CDC (April 7 2020): https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article We've seen talk about the reproductive rate. A R0 of 3 means that every infected person infects another 3 people. (3Blue1Brown has a nice video on Covid and exponential growth: https://www.youtube.com/watch?v=Kas0tIxDvrg) Here the CDC calculates a mean growth of 5.7. This would suggest that Covid is SUBSTANTIALLY more contagious than originally thought, this __doesn't__ mean it is twice as infectious because we're working with exponentials (again see why R0 of 2 is a big difference from R0 of 3 in the 3B1B video). So we're all fucked, right? Maybe not. This result is consistent with the Stanford team, suggesting that this virus is spreading rapidly and infecting many more people than we initially thought. This again matches Fauci's thoughts that the actual CFR is below 1%. So how deadly is it?

Ioannidis (April 8 2020) https://www.medrxiv.org/content/10.1101/2020.04.05.20054361v1 Ioannidis, who we saw in the Stanford paper, claims that there is very little risk of death for those that are under 65. Though health care systems, government actions, and what people are doing all play a role here. So why are we all social distancing? Why does Italy have such a high number of deaths? If we look at this paper more, we can see Table 2 refer to the number of people below 65 in different countries and states. It should now be no surprise that Italy has a very old population. 76.99% is below 65 where as in NYC 86.37% is below 65. NYC has a younger population. But this brings us back to why we are social distancing. From the very beginning it has been about protecting those that are immunocompromised, most notably the elderly. There's a lot of misinformation spreading about this virus and a lot of fear being generated. We must not fear, fear is the mindkiller. If we do not calm down and pay attention, it will bring total obliteration. It is important to remember that many of the sources we get information from are sensationalized (maybe that's why they always report the highest number? Maybe that's why MSNBC and FOX will always take opposite positions no matter the issue?). The Soviets had an old saying that many now say in science, "Trust but verify". So here's your papers and your science to verify what you hear from the news, friends, and family. You can point them towards these resources. I hope this helps. Note: I am not condoning the actions of those idiots in the streets protesting. Stay the fuck home. If you're going to protest, protest from home.