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1/ Lockdowns aren’t born equal. What are we really expecting to achieve? Another irrelevant thread from yours truly @maestro_rayo and @federicolois
2/ “Bro, you dumb. Of course Lockdowns work!” we have heard, over and over. Also “Lockdowns don’t work at all, bro”. That begs the question. What is “A Lockdown”? What is the goal? How effective are LDs at achieving those goals? And what are the costs and risks?
3/ We know ‘a certain’ respiratory disease is transmitted (mostly) by human to human contact. You heard it, droplets, aerosols. We might fear fomites and zoonotic hosts but let’s stick to “overwhelming majority of transmission is human to human”.
4/ We want to control spreading. Easy right? We keep people apart from one another, say 2 weeks, then the virus will die out. That, in theory, doesn’t sound too bad. Close the bridge. Stay home. Save lives. Easy peasy.
5/ But, what is a Lockdown then? We stock up on food for 2 weeks and don’t leave our houses? Do we allow people to go to the supermarket or the pharmacy if in need? To walk their dogs? To visit family? How about bringing them food? Who brings us food when we order online?
6/ As you can imagine, there are as many “Lockdowns” as who tried to implement them. From “Wuhan style” hazmat suit compliance level Lockdown to multiple relaxed versions all the way to Sweden-like (max groups of 50) “slow the spread effects” kind.
7/ Ohhh wait!!! Did you just say Sweden had a lockdown?
8/ It is safe to say by now given how broad the definition for lockdown is that the only thing we can be sure about is: “Whatever we think it is a Lockdown is not the strict definition of a Lockdown”. So let's go back to the basics, shall we?
9/ What is the goal of a Lockdown? Is it “eradication”, “suppression” or “mitigation”? In other words, do we want to “Crush the curve” and get rid of the virus? Do we want to ‘ temporarily’ crush the curve and do this all over again next winter?
10/ Do we want to flatten the curve so as not to overwhelm hospitals but build enough community immunity to minimize future outbreaks? Do we know what we wanted to achieve?
11/ We heard a lot about “Flatten the curve” in the early days (mitigation), two influential manuscripts where calling for a strategy deemed “iterative suppression”, “accordion” or “hammer and the dance”.
https://medium.com/@tomaspueyo/coronavirus-the-hammer-and-the-dance-be9337092b56
https://www.imperial.ac.uk/mrc-global-infectious-disease-analysis/covid-19/report-9-impact-of-npis-on-covid-19/
https://medium.com/@tomaspueyo/coronavirus-the-hammer-and-the-dance-be9337092b56
https://www.imperial.ac.uk/mrc-global-infectious-disease-analysis/covid-19/report-9-impact-of-npis-on-covid-19/
12/ Their point was: ‘classic mitigation’ will overwhelm the healthcare system, so we must suppress (through lockdowns), buy time, suppress again, rinse and repeat until vaccine. Both were heavily based on modeling. At the time, it sounded reasonable. Was it?
13/ We can see that general population Lockdowns had a variety of effects. First, although countries locked down at the same time, not all countries and cities were at the same epidemiological state.
14/ We can roughly divide them as: Very low infection levels, Somewhat widespread infection but not epidemic yet, and Epidemic transmission. And we can classify the outcomes as: Successful early suppression, Successful late suppression, Unsuccessful suppression, and “Too late”.
15/ Let’s illustrate these by example and try to motivate the reasons for their outcomes. First, successful suppression could be New Zealand: early, hard lockdowns, TTI, border closures, and an extended suppression (they needed second LDs in Auckland to contain new outbreaks).
16/ Successful late suppression could be many European cities, such as Madrid or Milan (very late), or Prague and Budapest (earlier) that managed to temporarily bring numbers down, but as we know now, not having achieved enough widespread immunity to prevent future outbreaks.
17/ As strange as it sounds, this phenomenon was NOT unexpected at all and was actually very clearly depicted in the now infamous Imperial College London Report 9 (it was quite spot on in many regards, although worse case scenario projections were too conservative):
18/ It can be said Latin America is a good example of “unsuccessful suppression”. In a sense they managed to delay outbreaks for months (due to favorable seasonality) but enforcing strict lockdowns for long periods ended up in de-facto opening up (willingly or unwillingly).
19/ It can be argued that the end result is no more than a progressive loosening uniform mitigation. Bogotá (Colombia) and Buenos Aires (Argentina) metropolitan areas, the prime examples in Latin America.
20/ Last, there are cities that went for hard suppression, arguably too late, such as New York or even Wuhan. In NYC, by sending infected people home, they even made things worse to some degree. This has been argued by looking at dates of Lockdowns vs. for instance death curves.
21/ A large degree of community immunity as we see in NYC now (no apparent epidemic outbreaks) seem to support this theory.
22/ But logic dictates that we did this to not overload the healthcare systems. Were they spared at least? No way to know, reality support models appear to have been exaggerated in this regard as there is no such thing as people NOT reacting to a perceived threat anyways.
23/ Yes, there was stress to systems but Wuhan’s newly built hospitals were hardly used, and NYC ship-hospitals were completely empty.
https://www.cnbc.com/2020/04/17/nearly-90percent-of-the-us-navy-hospital-ship-in-new-york-is-empty-amid-coronavirus-fight.html
https://www.theguardian.com/world/2020/feb/12/what-chinas-empty-new-coronavirus-hospitals-say-about-its-secretive-system
https://www.cnbc.com/2020/04/17/nearly-90percent-of-the-us-navy-hospital-ship-in-new-york-is-empty-amid-coronavirus-fight.html
https://www.theguardian.com/world/2020/feb/12/what-chinas-empty-new-coronavirus-hospitals-say-about-its-secretive-system
24/ What are the costs of Lockdowns? Level headed public health experts knew then and tried to warn about (like @BallouxFrancois, @sdbaral and others), and we know now. There are incredible costs in terms of mental health, economic ruin, deaths by all causes, etc.
25/ Some of these costs are short term, some are longer term, some are even paid in cash, others are paid in lives, but they are pretty much well documented. https://thepriceofpanic.com/
26/ Such staggering costs affect the world globally, to globalization of food supply chains and domino effects of the global economy. For instance UNICEF and FAO estimate grim prospects for childhood globally.
https://data.unicef.org/covid-19-and-children/
https://data.unicef.org/covid-19-and-children/
27/ So we can draw the following conclusions: Lockdowns might possibly delay or mitigate a pandemic at great economic and human cost, only if sufficiently strict and at sufficiently low transmission levels. They can also come late and make things worse.
28/ Yes, there might be some benefits to suppression, if treatments advance and countries might buy time to improve their healthcare system. But, one would need to seriously compare these benefits against the costs, and we haven’t seen anyone doing this analysis so far.
29/ Do you believe at this point that “Eradication” is possible?
30/ Reality showed that Eradication is elusive, so the best suppression can only count on an eventually effective (and hopefully sterilizing) vaccine. So far none of the ones at phase 3 ensure there won't be contagion, only that cases will be milder. https://twitter.com/maestro_rayo/status/1317662935003648000
31/ Does this come as a surprise? Is this the first time in history we attempted to lockdown to mitigate or suppress a pandemic? What do you think?
32/ Of course not. Lockdowns are pretty much the state of the art of the XII century (yes that is 12). @who had reviewed 100 years of evidence and several flu pandemics in 2019, and not surprisingly, they never mention Lockdowns as a suitable Nonpharmaceutical intervention (NPI)
33/ On the contrary, they explicitly recommend against “quarantines for exposed” and say one should be extremely careful when shutting down workplaces, since obviously, not everybody can work from home.
https://apps.who.int/iris/bitstream/handle/10665/329438/9789241516839-eng.pdf
https://apps.who.int/iris/bitstream/handle/10665/329438/9789241516839-eng.pdf
34/ A 2006 study specifically aimed to understand the impact of NPIs for pandemic influenza also advises against Lockdowns.
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.552.1109&rep=rep1&type=pdf
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.552.1109&rep=rep1&type=pdf
35/ The 2011 report from @who warns about balancing Influenza pandemics against overall health. SARS-CoV-2 is not exactly influenza, but it is characterized as an Influenza-Like-Illness (ILI), like the other 4 human coronaviruses in circulation.
https://www.who.int/bulletin/volumes/89/7/11-089086/en/
https://www.who.int/bulletin/volumes/89/7/11-089086/en/
36/ If you read so far, we can only say WOW!!! This was probably our longest thread. We hope that all this information helps you to take informed decisions regardless of your position on Lockdowns. If you like it, don't forget to RT the first tweet. 
