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Tuesday, March 17, 2020

Catching up with the coronavirus

Just some of my recent if disjointed thoughts on the coronavirus (i.e. SARS-CoV-2/COVID-19):

1. It's been a public health disaster in Italy. Maybe it would have been regardless of what Italy did. At the same time, it might be worth keeping in mind what Johns Hopkins infectious disease specialist and critical care physician Amesh Adalja pointed out nearly a week ago when Italy first began its lockdowns, etc.:

2. However, the good news for us is we're not Italy. Not yet. I've posted in the past about what measures our physicians and hospitals are undertaking. For example, "How are physicians preparing for coronavirus?". Also, "How to treat coronavirus in the ICU". And "Plasma therapy for coronavirus".

3. By contrast, some of the Asian nations seem to be doing well. For instance, it looks like Singapore is doing really well (source). Likewise it seems South Korea, Taiwan, and Hong Kong. In fact, Dr. Scott Gottlieb tweeted today: "South Korea continues to show signs that its epidemic is abating".

4. I think that's due to several reasons, though I could be mistaken since I haven't closely followed things:

  1. These Asian nations have had more recent experiences with epidemics in their regions than have many other nations. So they've already had structures set up and in place which they could rapidly mobilize (e.g. command centers tasked to deal with viral outbreaks).
  2. Also, they've implemented early (Dec 2019) and extensive testing ("drive through testing") of the general population to isolate pockets of outbreaks and stamp them out before they could spread too widely. We might be past this point already since we hadn't started rolling out the tests until recently.
  3. Likewise they've placed temperature monitoring stations at large office buildings and at their borders. If a person had a temperature and other signs and symptoms of sickness, they were asked to return home and rest. A health care worker would follow-up with them.
  4. The early use of drugs like chloroquine and hydroxychloroquine on certain patients, though our physicians debate its efficacy with the coronavirus. For example, I know Stanford has preferenced trialing the antiviral remdesivir.
  5. Admittedly some of what these Asian nations have done doesn't entirely sit well with me as someone who deeply values Constitutional principles and the Bill of Rights.

5. I think the best current estimates for the transmission rates (R0) of the coronavirus are between approximately 2-4. That means for every one person who has been infected with the coronavirus, they'll infect 2-4 more people on average. The best current estimates for its case fatality rate (CFR) are between approximately 0.5% to 3.4%. Basically that means the risk someone will die if they contract the coronavirus and develop symptoms.

6. For comparison, the seasonal flu has an R0 of approximately 1.3, while it has a CFR of approximately 0.1%. It's thought the Spanish flu in 1918 had an R0 between 1.4-2.8 and a CFR between 3-5%.

7. By the way, influenza causes the seasonal flu, but it also caused the Spanish flu (1918), the Asian flu (1957), the Hong Kong flu (1968), the Russian flu (1977), and the Swine flu (2009). As I wrote here, many infectious disease experts argue influenza is the most deadly virus for humanity. Of course, coronaviruses have likewise been worrying in recent decades (i.e. SARS, MERS, and our current coronavirus aka SARS-2). But I would never dismiss influenza as a real and present danger.

8. Both R0 and CFR will have regional variations. There's no single R0 or CFR.

9. That in turn is partly based on how public health services respond to the pandemic. As I mentioned above, Italy has been overwhelmed, so I wouldn't be surprised if their CFR is much higher, whereas the Asian nations I mentioned above might have lower CFRs in part due to their responses. Last I checked, I believe South Korea's CFR was 0.6%.

10. All that said, R0 and CFR are dynamic. That's because we're still in the midst of the pandemic. We won't know its true impact until it's all over. Where will we end up falling - closer to South Korea or Italy? Better/worse than one or the other?

11. In addition, it's worth noting that these calculations are based on epidemiological models. However an issue with these models is that they depend on certain assumptions which could be debated as well as depend on what data is fed into these models. What's more, if we change a small variable, it could have a larger effect in these models. These are some of the limitations in these models.

12. However, without these models, I don't know if we would have better ways to predict how bad the coronavirus will be.

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