On the Efficacy of Social Distancing

Posted byRhapsodySeaPosted inUncategorized

It has been two weeks since “social distancing” has been practiced in the United States. But we have seen a surge in the stress of the health care system this week. Not only a surge in COVID19 positive patients but, also many others with negative results. I want to share some of my thoughts on this matter. I don’t think that what I state is 100% correct, as I am still warping my head around a lot of facts, and I only have limited information. But I will try my best to be accurate with the information, and I will include where I have found the data for my argument. I want to share about the perspective as an outsider that is someone with limited information. Take this only as an opinion of an outsider.

Here is a very informative website that CDC. It keeps data about flu like diseases all across the U.S. But at the time of writing, it only contains the information of week 12 of 2020, that ends at march 21st, 1st week of the social distancing.

https://www.cdc.gov/flu/weekly/index.htm#ILIActivityMap

Couple of notes first:

  1. From the CDC website, only 10%-20% of flu like patients are test positive as influenza, which means, as the data suggests, we have very little understanding of the pathogens and cause of the other 80% – 90% patients.
  2. There are 24,000 deaths related to flu so far, but only 155 death tests influenza positive even though about 10%-20% patients test positive. If influenza has the same death rate of other flu like diseases, the death of influenza should be close to 2.4k to 4.8k. This significantly lower number, consistent every year, is an indication of the influenza’s morality rate is much lower than the general flu. Probably due to our better understanding of the disease, and the efficacy of the antiviral treatment. Though that claim would require more data for support. But also, influenza mortality rate is not the same as flu mortality rate.
  3. If we calculate mortality rate as number of tests / number of death. In 2018-2019 flu season, there are 1,208,294 lab tests run, and 34,157 death (see https://www.cdc.gov/flu/about/burden/2018-2019.html) then the death rate would be a whooping 2.8% (the number will be even higher if we exclude influenza positive cases). But if we count it as medical visit (16,520,350) / number of death, the number would be 0.2%. How we define the term mortality rate changes the mortality rate. I hope that readers keep that in mind when reading about mortality rate of COVID19.

Now, to the main question: is the social distancing working? Why is there such an acute increase of COVID19 cases and stress in the hospital system in the past week?

Here is my hypothesis. I am no epidemiologist, and I only have access to limited information, so take what I stated here with a grain of salt.

I think social distancing is working, but the surge of patients in the hospital this week is due to the panic two weeks ago, that many people waiting in long lines in the stores during the weekend has spread air born diseases. The surge in COVID19 positive tests is a combination of the effect of the panic two weeks ago, and the generally more tests we are conducting through out the nation.

If my hypothesis is correct, there should be three results in the following weeks:

  1. If the peak is caused by the panic, the CDC data of week of 13 or 14 of 2020 flu diseases should show an increasing in all flu like diseases, including influenza, given the incubation period of those diseases is about a week or two.
  2. If the social distancing is working, we should see a decreasing in all flu like diseases follows, as the continuation of the enforcement of social distancing.
  3. If the spread of COVID19 is not because that COVID19 is far more contagious than other flu like diseases but of some other causes (such as panic), the trend of increasing/decreasing number of cases should be similar between COVID19 positive and negative results among patients with flu like symptoms.

I know that we want to think there is a ground truth of morality rate or the spread rate of a given disease. But those numbers are just approximations we constructed to make sense of the disease. The world is complex, and there is rarely a single cause for any of the events. How we react and what we do, in term changes how fast the disease spread and how deadly the disease is. The deadliness of the 1918 Spanish flu probably wasn’t contributed to the flu alone. But also the economical and heath situation of at the end WWI, where starvation strikes through Europe, and many civilians all over the world works for long hours in poor working conditions to maintain the demand of the war production. I would argue that the WWI’s impact on the society has far worsened the impact of the Spanish flu, as through out history, war often aggravate diseases. So is black death and 100 years war. We are all players in this world and we all make impacts on how the future will play out, and history is never the cause of a single factor, and what information we choose to analyse the events, shapes how we see the events. How we response to the disease and how we treat the disease all plays a role (sometimes even a critical one) in deciding how fast and how deadly the disease is. Sometime our impact is positive, as the invention of antibiotics and modern sanitation projects, sometimes the impact is negative, as the effect of the WWI, and the pollution, inequality, and poor working conditions accompanied with industrialization.

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