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Some Notes for Our Global & Local Response to the Current Coronavirus Pandemic.

A “very personal, in-pencil, will-update-with-help” page by Lucas Gonzalez Santa Cruz, (retired) Epidemiologist, PhD.

Contact me on @lucasgonzalez.

Version: 24 Sep 2020.

Based on “Preparedness and response to a severe flu pandemic” (FluSCIM):, which I was commissioned to write after 2009, and was published in 2011.

Introduction - why worry & act?

I’m interested in severe respiratory pandemics. Two examples:

Around 2005, the CDC of the USA attempted to express the severity of an influenza pandemic in parallel with that of tropical storms, using categories 1 to 5, based simply on the proportion of deaths between those with symptoms, also known as “case fatality rate” or CFR. Cat 3 would have been “30% fall ill, 0.1-1% die”. Cat 4 started at CFR 1%. Cat 5, at 2%. In 2009, the WHO included other factors, such as the response to the crisis.

This covid pandemic:

One important thing is it’s not over yet, at all. Most people haven’t caught the virus. Winter is coming. There’s room for much worse.

Severity in a respiratory pandemic means it can exhibit self-amplifying loops that make it worse. To make things better, governance matters, and individual & networked action matters. In some places or times, it will make sense to be able to lend a hand if governance is good, or heavily complement it if it isn’t - a sort of “friendly and effective pandemic swadeshi”, if you like. For that we need simple measures anyone can take.

We’re a species that knows how to do cooperation. On the other hand, we are also very capable of fighting each other. So, “how are we going to do this?” is an important question. Also, this is just today’s crisis, and immediately we’re facing poverty, slavery, climate crisis and ecocide. So it will be good if we learn as much as possible from this particular challenge.

One more thing about learning: truth is hard on the ego, and on our inherited culture. “First principles”, “epistemological humility”, keeping a list of “known unknowns”, learning from the many who know more than us - those are our superpowers. So maybe we need to first be humble, then (hopefully) right enough, then clear (so we understand each other), then… loud!

Science - how do things work?

See for instance summary by @erictopol, and “immunity is complicated” by @edyong.

It’s an RNA virus, and it mutates more slowly than flu, but is already well adapted, so it doesn’t really need to learn new tricks, and has lots of population available. It latches on to ACE receptors in many organs.

Infectivity is maximum around the time when symptoms (if there are any) appear. Infected people may not show symptoms and still be contagious. Not sure if long-haulers are contagious. Not sure how contagious children are, or at which point (probably in teen years?) they become more like adults.

The virus doesn’t like soap (or alcohol on your skin), is diluted by breeze in open spaces, and inactivated by whatever number of minutes of direct sunlight. Think of it as a microscopic machine that breaks down in certain physical circumstances.

It doesn’t transmit evenly: a few people, or rather a limited range of known situations (“superspreader events”) are responsible for most of the spread. It loves crowds that talk, sing, do exercise, in close proximity - think a successful karaoke bar. It may make use of air conditioning in a room; not sure if across buildings, I think not or at least not much. (Some suggest faecal aerosols in some circumstances.)

Wide range of severity. Symptoms can be zero or barely noticeable. It can be flu-like, severe (with damage in many organs) and deadly, particularly in the elderly. Some cases have varied symptoms for a long time; maybe some will have symptoms permanently, and be at risk of other diseases.

Time? Until infectiousness, until symptoms, until severity, until death. We know infectiousness happens early. We must be faster than the virus.

Situational awareness - what’s going on?

I could use better links for this - work in progress

Prevent = “prevention triad” = RIP:

We have exactly one goal: we want to stop virus going from person A (infected) to B (susceptible).

No single measure is perfect, so we stack them, apply them early, and facilitate them for higher compliance. This means we use several measures at the same time, sooner rather than later, and helping each other so that a higher percentage of us do the right thing. An example is we pay people to isolate, as they are doing society a service. Or we try and have fewer people in trains, and also add masks and good ventilation.

(R)educe opportunities for contagion: don’t put person A in the same room as person B.

(I)ntercept the virus on its way from A to B: Put something in between.

(P)rotect people by improving their immunity. We think of vaccines if/when/as available, but we might also include general risk factor reduction if possible (poverty), general health (lose weight but never in a rush, quit smoking) and nutrition (supplements?). We would do this first for the susceptible and/or the essential, and eventually for many or even most people in the world.


I don’t have good links for any of this - work in progress

Manage - what to do (before or when) things get complicated?

Vital: keeping people alive

Important: but you need to be alive first

Contact tracing - a tool for “reduce”:

I don’t have good links for any of this - work in progress

A daily tool for learning from our actions: