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<!-- THE ACTUAL ARTICLE - - - - - - - - - - - - - -->
<!-- - - - - - - - - - - - - - - - - - - - - - - -->
<!--
<article>
<div class="section">
<div>
<h1>What Happens Next?</h1>
<h2>COVID-19 Futures, Explained With Playable Simulations</h2>
<h3>(28 min play/read)</h2>
</div>
<div>
<h1>What Happens Next?</h1>
<h2>COVID-19 Futures, Explained With Playable Simulations</h2>
<h3>by Marcel Salathé (epidemiologist) and Nicky Case (art/code)</h3>
<h3>🕐 28 min play/read</h3>
</div>
</div>
<p><strong>{WIP, DON&#39;T SHARE YET THX!}</strong></p>
<p><strong>[ Hi early-access folks! Don&#39;t share this yet, I&#39;m still polishing it up. Once you&#39;re done please give feedback on the Patreon comments. I&#39;ll add you to the playtester credits if you want, thanks! ^_^ ]</strong></p>
<p>. . .</p>
<p>&quot;The only thing to fear is fear itself&quot; was stupid advice.</p>
<p>Sure, don&#39;t hoard toilet paper but if policymakers fear fear itself, they&#39;ll downplay dangers to us to avoid &quot;mass panic&quot;. Fear&#39;s not the problem, it&#39;s how we <em>channel</em> our fear. Fear gives us energy to deal with dangers now, and prepare for dangers later.</p>
<p>Sure, don&#39;t hoard toilet paper but if policymakers fear fear itself, they&#39;ll downplay real dangers to avoid &quot;mass panic&quot;. Fear&#39;s not the problem, it&#39;s how we <em>channel</em> our fear. Fear gives us energy to deal with dangers now, and prepare for dangers later.</p>
<p>Honestly, we (Marcel, epidemiologist + Nicky, art/code) are worried. We bet you are, too! That&#39;s why we&#39;ve channelled our fear into making these <strong>playable simulations</strong>, so that <em>you</em> can channel your fear into understanding:</p>
@ -80,7 +82,7 @@
<li><strong>The Next Few Years</strong> (loss of immunity? no vaccine?)</li>
</ul>
<p>This guide (published April 30th, 2020<sup id="fnref1"><a href="#fn1" rel="footnote">1</a></sup>) is meant to give you hope <em>and</em> fear. To beat COVID-19 <strong>in a way that also protects our mental &amp; financial health</strong>, we need optimism to create plans, and pessimism to create backup plans. As Gladys Bronwyn Stern once said, <em>“The optimist invents the airplane and the pessimist the parachute.”</em></p>
<p>This guide (published May 1st, 2020<sup id="fnref1"><a href="#fn1" rel="footnote">1</a></sup>) is meant to give you hope <em>and</em> fear. To beat COVID-19 <strong>in a way that also protects our mental &amp; financial health</strong>, we need optimism to create plans, and pessimism to create backup plans. As Gladys Bronwyn Stern once said, <em>“The optimist invents the airplane and the pessimist the parachute.”</em></p>
<p>So, buckle in: we&#39;re about to experience some turbulence.</p>
@ -94,13 +96,11 @@
<p><strong>Epidemiologists use epidemic simulators to learn how not to crash humanity.</strong></p>
<p>So, let&#39;s make a simple &quot;epidemic flight simulator&quot;! In this simulation, <icon i></icon> Infectious people can turn <icon s></icon> Susceptible people into more <icon i></icon> Infectious people:</p>
<p>So, let&#39;s make a very, <em>very</em> simple &quot;epidemic flight simulator&quot;! In this simulation, <icon i></icon> Infectious people can turn <icon s></icon> Susceptible people into more <icon i></icon> Infectious people:</p>
<p><img src="pics/spread.png" alt=""></p>
<p>It&#39;s estimated that, <em>at the start</em> of a COVID-19 outbreak, the virus jumps from an <icon i></icon> to an <icon s></icon> <em>approximately</em> every 4 days.<sup id="fnref2"><a href="#fn2" rel="footnote">2</a></sup></p>
<p>[TODO: Actually fill out source / footnotes]</p>
<p>It&#39;s estimated that, <em>at the start</em> of a COVID-19 outbreak, the virus jumps from an <icon i></icon> to an <icon s></icon> every 4 days, <em>on average</em>.<sup id="fnref2"><a href="#fn2" rel="footnote">2</a></sup> (remember, there&#39;s a lot of variation)</p>
<p>If we simulate &quot;double every 4 days&quot; <em>and nothing else</em>, on a population starting with just 0.001% <icon i></icon>, what happens? </p>
@ -130,21 +130,25 @@
<p>But, this simulation is <em>still</em> wrong. We&#39;re missing the fact that <icon i></icon> Infectious people eventually stop being infectious, either by 1) recovering, 2) &quot;recovering&quot; with lung damage, or 3) dying.</p>
<p>For simplicity&#39;s sake, let&#39;s pretend that all <icon i></icon> Infectious people become <icon r></icon> Recovered. (Just remember that, in reality, some of them are dying.) <icon r></icon>s can&#39;t be infected again, and let&#39;s pretend <em>for now!</em> that they stay immune for life.</p>
<p>For simplicity&#39;s sake, let&#39;s pretend that all <icon i></icon> Infectious people become <icon r></icon> Recovered. (Just remember that in reality, some are dead.) <icon r></icon>s can&#39;t be infected again, and let&#39;s pretend <em>for now!</em> that they stay immune for life.</p>
<p>With COVID-19, it&#39;s estimated you&#39;re <icon i></icon> Infectious for <em>approximately</em> 10 days.<sup id="fnref4"><a href="#fn4" rel="footnote">4</a></sup> Let&#39;s simulate a population starting at 100% <icon i></icon>, most of whom recover after 10 days, then most of the remainder recover after another 10 days, then most of <em>that</em> remainder recover after another 10 days, etc:</p>
<p>With COVID-19, it&#39;s estimated you&#39;re <icon i></icon> Infectious for 10 days, <em>on average</em>.<sup id="fnref4"><a href="#fn4" rel="footnote">4</a></sup> That means some folks will recover before 10 days, some after. <strong>Here&#39;s what that looks like, with a simulation <em>starting</em> with 100% <icon i></icon>:</strong></p>
<div class="sim">
<iframe src="sim?stage=epi-3" width="800" height="540"></iframe>
</div>
<p>This is the opposite of exponential growth, the <strong>exponential decay curve</strong>.</p>
<p>This is the opposite of exponential growth, the <strong>exponential decay curve.</strong></p>
<p>Now, what happens if you simulate S-shaped logistic growth <em>with</em> recovery?</p>
<p><img src="pics/graphs_q.png" alt=""></p>
<p>Let&#39;s find out:</p>
<p>Let&#39;s find out.</p>
<p><b style='color:#ff4040'>Red curve</b> is <em>current</em> cases <icon i></icon>,<br>
<b style='color:#999999'>Gray curve</b> is <em>total</em> cases (current + recovered <icon r></icon>),
starts at just 0.001% <icon i></icon>:</p>
<div class="sim">
<iframe src="sim?stage=epi-4" width="800" height="540"></iframe>
@ -152,27 +156,30 @@
<p>And <em>that&#39;s</em> where that famous curve comes from! It&#39;s not a bell curve, it&#39;s not even a &quot;log-normal&quot; curve. It has no name. But you&#39;ve seen it a zillion times, and beseeched to flatten.</p>
<p>This is the the <strong>SIR Model</strong><sup id="fnref5"><a href="#fn5" rel="footnote">5</a></sup><br>
<p>This is the the <strong>SIR Model</strong>,<sup id="fnref5"><a href="#fn5" rel="footnote">5</a></sup><br>
(<icon s></icon><strong>S</strong>usceptible <icon i></icon><strong>I</strong>nfectious <icon r></icon><strong>R</strong>ecovered)<br>
the second-most important idea in Epidemiology 101:</p>
the <em>second</em>-most important idea in Epidemiology 101:</p>
<p><img src="pics/sir.png" alt=""></p>
<p>NOTE: The simulations that inform policy are <em>far</em> more sophisticated than this! But the SIR Model can still explain the same findings, even if missing the nuances.</p>
<p><strong>NOTE: The simulations that inform policy are way, <em>way</em> more sophisticated than this!</strong> But the SIR Model can still explain the same general findings, even if missing the nuances.</p>
<p>Actually, let&#39;s add one more nuance: before an <icon s></icon> becomes an <icon i></icon>, they first become <icon e></icon> Exposed. This is when they have the virus but can&#39;t pass it on yet infect<em>ed</em> but not yet infect<em>ious</em>.</p>
<p><img src="pics/seir.png" alt=""></p>
<p>(This variant is called the <strong>SEIR Model</strong><sup id="fnref6"><a href="#fn6" rel="footnote">6</a></sup>, where the &quot;E&quot; stands for <icon e></icon> &quot;Exposed&quot;. Note this <em>isn&#39;t</em> the everyday meaning of &quot;exposed&quot;, when you might or might not have the virus. In this technical definition, &quot;Exposed&quot; means you definitely have it. Science terminology is bad.)</p>
<p>(This variant is called the <strong>SEIR Model</strong><sup id="fnref6"><a href="#fn6" rel="footnote">6</a></sup>, where the &quot;E&quot; stands for <icon e></icon> &quot;Exposed&quot;. Note this <em>isn&#39;t</em> the everyday meaning of &quot;exposed&quot;, when you may or may not have the virus. In this technical definition, &quot;Exposed&quot; means you definitely have it. Science terminology is bad.)</p>
<p>For COVID-19, it&#39;s estimated that you&#39;re <icon e></icon> infected-but-not-yet-infectious for <em>approximately</em> 3 days.<sup id="fnref7"><a href="#fn7" rel="footnote">7</a></sup> What happens if we add that to the simulation?</p>
<p>For COVID-19, it&#39;s estimated that you&#39;re <icon e></icon> infected-but-not-yet-infectious for 3 days, <em>on average</em>.<sup id="fnref7"><a href="#fn7" rel="footnote">7</a></sup> What happens if we add that to the simulation?</p>
<p><b style='color:#ff4040'>Red <b style='color:#FF9393'>+ Pink</b> curve</b> is <em>current</em> cases (infectious <icon i></icon> + exposed <icon e></icon>),<br>
<b style='color:#888'>Gray curve</b> is <em>total</em> cases (current + recovered <icon r></icon>):</p>
<div class="sim">
<iframe src="sim?stage=epi-5" width="800" height="540"></iframe>
</div>
<p>Not much, actually! How long you stay <icon e></icon> Exposed changes the ratio of <icon e></icon>-to-<icon i></icon>, and <em>when</em> the peak of current cases (<icon e></icon>+<icon i></icon>) happens... but the <em>height</em> of that peak, and the total % of people infected in the end, stays the same.</p>
<p>Not much changes! How long you stay <icon e></icon> Exposed changes the ratio of <icon e></icon>-to-<icon i></icon>, and <em>when</em> current cases peak... but the <em>height</em> of that peak, and total cases in the end, stays the same.</p>
<p>Why&#39;s that? Because of the <em>first</em>-most important idea in Epidemiology 101:</p>
@ -186,11 +193,11 @@
<p><strong>R<sub>0</sub></strong> (pronounced R-nought) is what R is <em>at the start of an outbreak, before immunity or interventions</em>. R<sub>0</sub> more closely reflects the power of the virus itself, but it still changes from place to place. For example, R<sub>0</sub> is higher in dense cities than sparse rural areas.</p>
<p>(Most news articles and even some scientific papers! confuse R and R<sub>0</sub>. Again, science terminology is bad)</p>
<p>(Most news articles and even some research papers! confuse R and R<sub>0</sub>. Again, science terminology is bad)</p>
<p>The R<sub>0</sub> for &quot;the&quot; seasonal flu is around 1.28<sup id="fnref8"><a href="#fn8" rel="footnote">8</a></sup>. This means, at the <em>start</em> of a flu outbreak, each <icon i></icon> infects 1.28 others <em>on average.</em> (If it sounds weird that this isn&#39;t a whole number, remember that the &quot;average&quot; mom has 2.4 children. This doesn&#39;t mean there&#39;s half-children running about.)</p>
<p>The R<sub>0</sub> for COVID-19 is estimated to be around 2.2<sup id="fnref9"><a href="#fn9" rel="footnote">9</a></sup>, though a not-yet-finalized CDC study estimates it was 5.7(!) in Wuhan.<sup id="fnref10"><a href="#fn10" rel="footnote">10</a></sup></p>
<p>The R<sub>0</sub> for COVID-19 is estimated to be around 2.2,<sup id="fnref9"><a href="#fn9" rel="footnote">9</a></sup> though one <em>not-yet-finalized</em> study estimates it was 5.7(!) in Wuhan.<sup id="fnref10"><a href="#fn10" rel="footnote">10</a></sup></p>
<p>In our simulations <em>at the start &amp; on average</em> an <icon i></icon> infects someone every 4 days, over 10 days. &quot;4 days&quot; goes into &quot;10 days&quot; two-and-a-half times. This means <em>at the start &amp; on average</em> each <icon i></icon> infects 2.5 others. Therefore, R<sub>0</sub> = 2.5. (caveats:<sup id="fnref11"><a href="#fn11" rel="footnote">11</a></sup>)</p>
@ -206,7 +213,7 @@
<iframe src="sim?stage=epi-6b&format=calc" width="285" height="390"></iframe>
</div>
<p>When enough people have natural immunity, R &lt; 1, and the virus is contained! This is called <strong>herd immunity</strong>, and while it&#39;s <em>terrible</em> policy (we&#39;ll explain why later it&#39;s not for the reason you may think!), it&#39;s essential to understanding Epidemiology 101.</p>
<p>When enough people have immunity, R &lt; 1, and the virus is contained! This is called <strong>herd immunity</strong>. For flus, herd immunity is achieved <em>with a vaccine</em>. Trying to achieve &quot;natural herd immunity&quot; by letting folks get infected is a <em>terrible</em> idea. (But not for the reason you may think! We&#39;ll explain later.)</p>
<p>Now, let&#39;s play the SEIR Model again, but showing R<sub>0</sub>, R over time, and the herd immunity threshold:</p>
@ -214,7 +221,7 @@
<iframe src="sim?stage=epi-7" width="800" height="540"></iframe>
</div>
<p>Note: Total cases (gray curve) does not stop at herd immunity, but <em>overshoots</em> it! And it does this <em>exactly when</em> current cases (pink curve) peaks. (This happens no matter how you change the settings try it for yourself!)</p>
<p><strong>NOTE: Total cases <em>does not stop</em> at herd immunity, but overshoots it!</strong> And it crosses the threshold <em>exactly</em> when current cases peak. (This happens no matter how you change the settings try it for yourself!)</p>
<p>This is because when there are more non-<icon s></icon>s than the herd immunity threshold, you get R &lt; 1. And when R &lt; 1, new cases stop growing: a peak.</p>
@ -224,7 +231,7 @@
<p><strong>This means: we do NOT need to catch all transmissions, or even nearly all transmissions, to stop COVID-19!</strong></p>
<p>It&#39;s a paradox. COVID-19 is extremely contagious, yet to contain it, we &quot;only&quot; need to stop more than 60% of infections. 60%?! If that was a school grade, that&#39;s a D-. But if R<sub>0</sub> = 2.5, cutting that by 61% gives us R = 0.975, which is R &lt; 1, virus is contained!<sup id="fnref12"><a href="#fn12" rel="footnote">12</a></sup></p>
<p>It&#39;s a paradox. COVID-19 is extremely contagious, yet to contain it, we &quot;only&quot; need to stop more than 60% of infections. 60%?! If that was a school grade, that&#39;s a D-. But if R<sub>0</sub> = 2.5, cutting that by 61% gives us R = 0.975, which is R &lt; 1, virus is contained! (exact formula:<sup id="fnref12"><a href="#fn12" rel="footnote">12</a></sup>)</p>
<p><img src="pics/r4.png" alt=""></p>
@ -248,7 +255,7 @@
<h3 id="toc_0">Scenario 0: Do Absolutely Nothing</h3>
<p>Around 1 in 20 people infected with COVID-19 need to go to an ICU (Intensive Care Unit).<sup id="fnref13"><a href="#fn13" rel="footnote">13</a></sup> In a rich country like the USA, there&#39;s 1 ICU per 3400 people.<sup id="fnref14"><a href="#fn14" rel="footnote">14</a></sup> Therefore, the USA can handle 20 out of 3400 people being <em>simultaneously</em> infected or, 0.6% of the population.</p>
<p>Around 1 in 20 people infected with COVID-19 need to go to an ICU (Intensive Care Unit).<sup id="fnref13"><a href="#fn13" rel="footnote">13</a></sup> In a rich country like the USA, there&#39;s 1 ICU bed per 3400 people.<sup id="fnref14"><a href="#fn14" rel="footnote">14</a></sup> Therefore, the USA can handle 20 out of 3400 people being <em>simultaneously</em> infected or, 0.6% of the population.</p>
<p>Even if we <em>more than tripled</em> that capacity to 2%, here&#39;s what would&#39;ve happened <em>if we did absolutely nothing:</em></p>
@ -258,17 +265,18 @@
<p>Not good.</p>
<p>That&#39;s what <a href="http://www.imperial.ac.uk/mrc-global-infectious-disease-analysis/covid-19/report-9-impact-of-npis-on-covid-19/">the March 16 Imperial College report</a> found: do nothing, and we run out of ICUs with 80%+ of the population infected.</p>
<p>That&#39;s what <a href="http://www.imperial.ac.uk/mrc-global-infectious-disease-analysis/covid-19/report-9-impact-of-npis-on-covid-19/">the March 16 Imperial College report</a> found: do nothing, and we run out of ICUs, with more than 80% of the population getting infected.
(remember: total cases <em>overshoots</em> herd immunity)</p>
<p>Even if only 0.5% of infected die a generous assumption when there&#39;s no more ICUs in a large country like the US, with 300 million people, 0.5% of 80% of 300 million = still 1.2 million dead... <em>IF we did nothing.</em></p>
<p>(Lots of news &amp; social media reported &quot;80%+ will be infected&quot; <em>without</em> &quot;IF WE DO NOTHING&quot;. Fear was channelled into clicks, not understanding. <em>Sigh.</em>)</p>
<p>(Lots of news &amp; social media reported &quot;80% will be infected&quot; <em>without</em> &quot;IF WE DO NOTHING&quot;. Fear was channelled into clicks, not understanding. <em>Sigh.</em>)</p>
<h3 id="toc_1">Scenario 1: Flatten The Curve / Herd Immunity</h3>
<p>The &quot;Flatten The Curve&quot; plan was touted by every public health organization, while the United Kingdom&#39;s original &quot;herd immunity&quot; plan was universally booed. They were <em>the same plan.</em> The UK just communicated theirs poorly.<sup id="fnref15"><a href="#fn15" rel="footnote">15</a></sup></p>
<p>Both plans, though, are horribly flawed.</p>
<p>Both plans, though, had a literally fatal flaw.</p>
<p>First, let&#39;s look at the two main ways to &quot;flatten the curve&quot;: handwashing &amp; physical distancing.</p>
@ -289,13 +297,15 @@
<p>Three notes:</p>
<ol>
<li><p>This <em>reduces</em> total cases! Lots of folks think &quot;Flatten The Curve&quot; spread outs cases without reducing the total. This is impossible in <em>any</em> Epidemiology 101 model. But because the news reported &quot;80%+ will be infected&quot; as inevitable, folks thought total cases will be the same no matter what. <em>Sigh.</em></p></li>
<li><p>Due to the extra interventions, current cases (pink curve) peaks <em>before</em> herd immunity is reached. And in fact, total cases doesn&#39;t overshoot, but <em>goes to</em> herd immunity the UK&#39;s plan! At that point, R &lt; 1, you can let go of all other interventions, and COVID-19 stays contained! Well, except for one problem...</p></li>
<li><p>This <em>reduces</em> total cases! <strong>Even if you don&#39;t get R &lt; 1, reducing R still saves lives, by reducing the &#39;overshoot&#39; above herd immunity.</strong> Lots of folks think &quot;Flatten The Curve&quot; spreads out cases without reducing the total. This is impossible in <em>any</em> Epidemiology 101 model. But because the news reported &quot;80%+ will be infected&quot; as inevitable, folks thought total cases will be the same no matter what. <em>Sigh.</em></p></li>
<li><p>Due to the extra interventions, current cases peak <em>before</em> herd immunity is reached. In fact, in this simulation, total cases only overshoots <em>a tiny bit</em> above herd immunity the UK&#39;s plan! At that point, R &lt; 1, you can let go of all other interventions, and COVID-19 stays contained! Well, except for one problem...</p></li>
<li><p>You still run out of ICUs. For several months. (and remember, we <em>already</em> tripled ICUs for these simulations)</p></li>
</ol>
<p>That was the other finding of the March 16 Imperial College report, which convinced the UK to abandon its original plan. Any attempt at <strong>mitigation</strong> (reduce R, but R &gt; 1) will fail. The only way out is <strong>suppression</strong> (reduce R so that R &lt; 1).</p>
<p>// TODO: pic difference</p>
<p>That is, don&#39;t merely &quot;flatten&quot; the curve, <em>crush</em> the curve. For example, with a...</p>
<h3 id="toc_2">Scenario 2: Months-Long Lockdown</h3>
@ -316,7 +326,7 @@
<h3 id="toc_3">Scenario 3: Intermittent Lockdown</h3>
<p>This solution was first suggested by the Imperial College report, and later again by a Harvard paper<sup id="fnref19"><a href="#fn19" rel="footnote">19</a></sup>.</p>
<p>This solution was first suggested by the March 16 Imperial College report, and later again by a Harvard paper<sup id="fnref19"><a href="#fn19" rel="footnote">19</a></sup>.</p>
<p><strong>Here&#39;s a simulation:</strong> (After playing the &quot;recorded scenario&quot;, you can try simulating your <em>own</em> lockdown schedule, by changing the sliders <em>while</em> the simulation is running! Remember you can pause &amp; continue the sim, and change the simulation speed)</p>
@ -324,7 +334,7 @@
<iframe src="sim?stage=int-4&format=lines" width="800" height="540"></iframe>
</div>
<p>This <em>would</em> keep cases below ICU capacity! We&#39;d just need to... shut everything down for few months, open up for a few, shut down for a few, open up for a few... and repeat until a vaccine is available. (And if there&#39;s no vaccine, repeat until herd immunity is reached... in 2022.)</p>
<p>This <em>would</em> keep cases below ICU capacity! And it&#39;s <em>much</em> better than an 18-month lockdown until a vaccine is available. We just need to... shut down for a few months, open up for a few months, and repeat until a vaccine is available. (And if there&#39;s no vaccine, repeat until herd immunity is reached... in 2022.)</p>
<p>Look, it&#39;s nice to draw a line saying &quot;ICU capacity&quot;, but there&#39;s lots of important things we <em>can&#39;t</em> simulate here. Like:</p>
@ -358,31 +368,37 @@
<p><img src="pics/timeline3.png" alt=""></p>
<p>This is called <strong>contact tracing</strong>, and it&#39;s a core part of Taiwan &amp; South Korea&#39;s successful strategies.</p>
<p>This is called <strong>contact tracing</strong>. It&#39;s an old idea, was used at an unprecedented scale to contain Ebola<sup id="fnref23"><a href="#fn23" rel="footnote">23</a></sup>, and now it&#39;s core part of how Taiwan &amp; South Korea are containing COVID-19!</p>
<p>Traditionally, contact tracing is done with in-person interviews, but that&#39;s too slow for COVID-19&#39;s ~48 hour window. That&#39;s why on March 31st, <a href="https://science.sciencemag.org/content/early/2020/04/09/science.abb6936">an Oxford study</a> recommended helping contact tracers with <em>contact tracing apps</em>.</p>
<p>(It also lets us use our limited tests more efficiently, to find pre-symptomatic <icon i></icon>s without needing to test almost everyone.)</p>
<p>Does that mean giving up privacy, giving in to Big Brother? Heck no! <a href="https://github.com/DP-3T/documents#decentralized-privacy-preserving-proximity-tracing">DP-3T</a>, a team of epidemiologists &amp; cryptographers (including one of us, Marcel Salathé) is <em>already</em> making a contact tracing app that reveals <strong>no info about your identity, location, who your contacts are, or even <em>how many contacts</em> you&#39;ve had.</strong></p>
<p>Traditionally, contacts are found with in-person interviews, but those <em>alone</em> are too slow for COVID-19&#39;s ~48 hour window. That&#39;s why contact tracers need help, and be supported by <em>NOT</em> replaced by contact tracing apps.</p>
<p>(This idea didn&#39;t come from &quot;techies&quot;: using an app to fight COVID-19 was first proposed by <a href="https://science.sciencemag.org/content/early/2020/04/09/science.abb6936">a team of Oxford epidemiologists</a>.)</p>
<p>Wait, apps that trace who you&#39;ve been in contact with?... Does that mean giving up privacy, giving in to Big Brother?</p>
<p>Heck no! <strong><a href="https://github.com/DP-3T/documents#decentralized-privacy-preserving-proximity-tracing">DP-3T</a></strong>, a team of epidemiologists &amp; cryptographers (including one of us, Marcel Salathé) is <em>already</em> making a contact tracing app with code available to the public that reveals <strong>no info about your identity, location, who your contacts are, or even <em>how many contacts</em> you&#39;ve had.</strong></p>
<p>Here&#39;s how it works:</p>
<p><img src="pics/dp3t.png" alt=""></p>
<p>(<a href="https://ncase.me/contact-tracing/">Here&#39;s the full comic</a>, and <a href="">here&#39;s a video adaptation by 3Blue1Brown</a>)</p>
<p>(&amp; <a href="https://ncase.me/contact-tracing/">here&#39;s the full comic</a>)</p>
<p>Along with similar teams like <a href="https://github.com/TCNCoalition/TCN#tcn-protocol">TCN Protocol</a> and <a href="https://pact.mit.edu/">MIT PACT</a>, they&#39;ve inspired Apple &amp; Google to bake privacy-first contact tracing <a href="https://www.apple.com/ca/newsroom/2020/04/apple-and-google-partner-on-covid-19-contact-tracing-technology/">directly into Android/iOS</a>. Next month, your local public health agency may ask you to download an app. If it&#39;s privacy-first &amp; open-source, please do!</p>
<p>Along with similar teams like TCN Protocol<sup id="fnref24"><a href="#fn24" rel="footnote">24</a></sup> and MIT PACT<sup id="fnref25"><a href="#fn25" rel="footnote">25</a></sup>, they&#39;ve inspired Apple &amp; Google to bake privacy-first contact tracing directly into Android/iOS.<sup id="fnref26"><a href="#fn26" rel="footnote">26</a></sup> (Don&#39;t trust Google/Apple? Good! The beauty of this system is it doesn&#39;t <em>need</em> trust!) Soon, your local public health agency may ask you to download an app. If it&#39;s privacy-first with publicly-available code, please do!</p>
<p>But what about folks without smartphones? Or infections through doorknobs? Or &quot;true&quot; asymptomatic cases? Contact tracing apps can&#39;t catch all transmissions... <em>and that&#39;s okay!</em> We don&#39;t need to catch <em>all</em> transmissions, just 60%+ to get R &lt; 1.</p>
<p>(rant about the confusion about pre-symptomatic vs. &quot;true&quot; asymptomatic:<sup id="fnref23"><a href="#fn23" rel="footnote">23</a></sup>)</p>
<p>(Rant about the confusion about pre-symptomatic vs &quot;true&quot; asymptomatic. &quot;True&quot; asymptomatics are rare:<sup id="fnref27"><a href="#fn27" rel="footnote">27</a></sup>)</p>
<p>Anyway, isolating cases would reduce R by up to 40%, and quarantining their contacts would reduce R by up to 50%<sup id="fnref24"><a href="#fn24" rel="footnote">24</a></sup>:</p>
<p>Isolating <em>symptomatic</em> cases would reduce R by up to 40%, and quarantining their <em>pre/a-symptomatic</em> contacts would reduce R by up to 50%<sup id="fnref28"><a href="#fn28" rel="footnote">28</a></sup>:</p>
<div class="sim">
<iframe src="sim?stage=int-4a&format=calc" width="285" height="340"></iframe>
</div>
<p>Thus, even without 100% contact quarantining, we can get R &lt; 1 <em>without a lockdown!</em> Much better for our mental &amp; financial health. (As for the cost to folks who have to self-isolate/quarantine, <em>governments should support them</em> subsidized paid leave, job protection, etc. Still way cheaper than intermittent lockdown.)</p>
<p>Thus, even without 100% contact quarantining, we can get R &lt; 1 <em>without a lockdown!</em> Much better for our mental &amp; financial health. (As for the cost to folks who have to self-isolate/quarantine, <em>governments should support them</em> pay for the tests, job protection, subsidized paid leave, etc. Still way cheaper than intermittent lockdown.)</p>
<p>We then keep R &lt; 1 until we have a vaccine, which turns susceptible <icon s></icon>s into immune <icon r></icon>s. Herd immunity, the <em>right</em> way:</p>
@ -390,6 +406,8 @@
<iframe src="sim?stage=int-4b&format=calc" width="285" height="230"></iframe>
</div>
<p>(Note: this calculator pretends the vaccines are 100% effective. Just remember that in reality, you&#39;d have to compensate by vaccinating <em>more</em> than &quot;herd immunity&quot;, to <em>actually</em> get herd immunity)</p>
<p>Okay, enough talk. Here&#39;s a simulation of:</p>
<ol>
@ -417,35 +435,33 @@
<p>What if R<sub>0</sub> is way higher than we thought, and the above interventions, even with mild distancing, <em>still</em> aren&#39;t enough to get R &lt; 1?</p>
<p>If so, here&#39;s a few supplements:</p>
<p>Remember, even if we can&#39;t get R &lt; 1, reducing R still reduces the &quot;overshoot&quot; in total cases, thus saving lives. But still, R &lt; 1 is the ideal, so here&#39;s a few other ways to reduce R:</p>
<p><strong>Masks For All:</strong></p>
<p><em>&quot;Wait,&quot;</em> you might ask, <em>&quot;I thought face masks don&#39;t stop you from getting sick?&quot;</em></p>
<p>You&#39;re right. Masks don&#39;t stop you from getting sick... they stop you from getting <em>others</em> sick.</p>
<p>You&#39;re right. Masks don&#39;t stop you from getting sick<sup id="fnref29"><a href="#fn29" rel="footnote">29</a></sup>... they stop you from getting <em>others</em> sick.</p>
<p><img src="pics/masks.png" alt=""></p>
<p>(sources for the comic: <sup id="fnref25"><a href="#fn25" rel="footnote">25</a></sup> <sup id="fnref26"><a href="#fn26" rel="footnote">26</a></sup> <sup id="fnref27"><a href="#fn27" rel="footnote">27</a></sup> <sup id="fnref28"><a href="#fn28" rel="footnote">28</a></sup>)</p>
<p>To put a number on it: surgical masks <em>on the sick person</em> reduce cold &amp; flu viruses in aerosols by 70%.<sup id="fnref30"><a href="#fn30" rel="footnote">30</a></sup> Reducing transmissions by 70% would be as large an impact as a lockdown!</p>
<p>Still, in science, one should only publish a finding if you&#39;re 95% sure of it. (...<em>should.</em><sup id="fnref29"><a href="#fn29" rel="footnote">29</a></sup>) Admittedly, the current evidence for face masks on COVID-19 <em>specifically</em>, rather than &quot;just&quot; colds and flus, is less than &quot;95% sure&quot;.</p>
<p>However, we don&#39;t know for sure the impact of masks on COVID-19 <em>specifically</em>. In science, one should only publish a finding if you&#39;re 95% sure of it. (...should.<sup id="fnref31"><a href="#fn31" rel="footnote">31</a></sup>) Masks, as of May 1st 2020, are less than &quot;95% sure&quot;.</p>
<p>But, pandemics are like poker. <strong>Make bets only when you&#39;re 95% sure, and you&#39;ll lose everything at stake.</strong> We <em>have</em> to make cost/benefit analyses under uncertainty.<sup id="fnref30"><a href="#fn30" rel="footnote">30</a></sup> Like so:</p>
<p>However, pandemics are like poker. <strong>Make bets only when you&#39;re 95% sure, and you&#39;ll lose everything at stake.</strong> As a recent article on masks in the British Medical Journal notes,<sup id="fnref32"><a href="#fn32" rel="footnote">32</a></sup> we <em>have</em> to make cost/benefit analyses under uncertainty. Like so:</p>
<p>Cost: If homemade cloth masks, same as the cost of all that soap for handwashing. If surgical masks, more expensive but still pretty cheap.</p>
<p>Benefit: Even if it&#39;s a 5050 chance of surgical masks reducing transmission by 0% or 70%<sup id="fnref31"><a href="#fn31" rel="footnote">31</a></sup>, the average &quot;expected value&quot; is still 35%, same as a half-lockdown! So let&#39;s guess-timate that surgical masks reduce R by up to 35%. (Again, you can challenge our assumptions by turning the sliders up/down)</p>
<p>Benefit: Even if it&#39;s a 5050 chance of surgical masks reducing transmission by 0% or 70%, the average &quot;expected value&quot; is still 35%, same as a half-lockdown! So let&#39;s guess-timate that surgical masks reduce R by up to 35%. (Again, you can challenge our assumptions by turning the sliders up/down)</p>
<p><strong>Here&#39;s a calculator of how masks reduce R! You can switch between cloth &amp; surgical:</strong> (assumes cloth masks are half as effective as surgical masks<sup id="fnref32"><a href="#fn32" rel="footnote">32</a></sup>)</p>
<p>[TODO: Actually allow toggling between cloth/surgical. Currently locked to cloth]</p>
<p><strong>Here&#39;s a calculator of how masks reduce R! You can switch between cloth &amp; surgical:</strong> (assumes cloth masks are 2/3 as effective as surgical masks<sup id="fnref33"><a href="#fn33" rel="footnote">33</a></sup>)</p>
<div class="sim">
<iframe src="sim?stage=int-6a&format=calc" width="285" height="380"></iframe>
</div>
<p>(other arguments for/against masks:<sup id="fnref33"><a href="#fn33" rel="footnote">33</a></sup>)</p>
<p>(other arguments for/against masks:<sup id="fnref34"><a href="#fn34" rel="footnote">34</a></sup>)</p>
<p>Masks <em>alone</em> won&#39;t get R &lt; 1. But if handwashing &amp; &quot;Test, Trace, Isolate&quot; only gets us to R = 1.10, having just 2/3 of people wear <em>cloth</em> masks would tip that over to R &lt; 1, virus contained!</p>
@ -453,9 +469,7 @@
<p>Okay, this isn&#39;t an &quot;intervention&quot; we can control, but it will help! Some news outlets report that summer won&#39;t do anything to COVID-19. They&#39;re half right: summer won&#39;t get R &lt; 1, but it <em>will</em> reduce R.</p>
<p>For COVID-19, every extra 1° Celsius (2.2° Fahrenheit) makes R drop by 1.2%.<sup id="fnref34"><a href="#fn34" rel="footnote">34</a></sup> The summer-winter difference in New York City is 15°C (60°F), so summer will make R drop by 18%.</p>
<p>[TODO: Fix weird arrow glitch]</p>
<p>For COVID-19, every extra 1° Celsius (2.2° Fahrenheit) makes R drop by 1.2%.<sup id="fnref35"><a href="#fn35" rel="footnote">35</a></sup> The summer-winter difference in New York City is 15°C (60°F), so summer will make R drop by 18%.</p>
<div class="sim">
<iframe src="sim?stage=int-6b&format=calc" width="285" height="220"></iframe>
@ -481,15 +495,23 @@
<iframe src="sim?stage=int-7&format=lines&height=620" width="800" height="620"></iframe>
</div>
<p>[TODO: Other options like temperature testing at malls, quarantines for travellers, replacing handshaking, etc]</p>
<p>Not to mention all the <em>other</em> interventions we could do, to further push R down:</p>
<ul>
<li>Travel restrictions/quarantines</li>
<li>Temperature checks at malls &amp; schools</li>
<li>Deep-cleaning public spaces</li>
<li><a href="https://twitter.com/V_actually/status/1233785527788285953">Replacing hand-shaking with foot-bumping</a></li>
<li>And all else human ingenuity shall bring</li>
</ul>
<p>. . .</p>
<p>We hope these plans give you hope. </p>
<p><strong>Even under a pessimistic scenario, it <em>is</em> possible to beat COVID-19, while protecting our mental and financial health.</strong> Use the lockdown as a restart, keep R &lt; 1 with privacy-protecting contract tracing, supplemented with at <em>least</em> cloth masks... and life can get back to a normal-ish!</p>
<p><strong>Even under a pessimistic scenario, it <em>is</em> possible to beat COVID-19, while protecting our mental and financial health.</strong> Use the lockdown as a &quot;reset button&quot;, keep R &lt; 1 with case isolation + privacy-protecting contract tracing + at <em>least</em> cloth masks for all... and life can get back to a normal-ish!</p>
<p>Sure, your hands may be dry. But you&#39;ll get to invite a date out to a comics bookstore! You&#39;ll get to go out with friends to watch the latest Hollywood cash-grab. You&#39;ll get to people-watch at a library, taking joy in people going about the simple business of <em>being alive.</em></p>
<p>Sure, you may have dried-out hands. But you&#39;ll get to invite a date out to a comics bookstore! You&#39;ll get to go out with friends to watch the latest Hollywood cash-grab. You&#39;ll get to people-watch at a library, taking joy in people going about the simple business of <em>being alive.</em></p>
<p>Even under the worst-case scenario... life perseveres.</p>
@ -505,16 +527,20 @@
<p>...<em>for how long?</em></p>
<p>There&#39;s been reports of folks who test positive again after recovering, but those were false positives. Still, the possibility of <strong>waning immunity</strong> is very real. Either a new mutant strain evolves, or your immune system just... forgets.</p>
<ul>
<li>COVID-19 is most closely related to SARS, which gave its survivors 2 years of immunity.<sup id="fnref36"><a href="#fn36" rel="footnote">36</a></sup></li>
<li>The coronaviruses that cause &quot;the&quot; common cold give you 8 months of immunity.<sup id="fnref37"><a href="#fn37" rel="footnote">37</a></sup></li>
<li>There&#39;s reports of folks recovering from COVID-19, then testing positive again, but it&#39;s unclear if these are false positives.<sup id="fnref38"><a href="#fn38" rel="footnote">38</a></sup></li>
<li>One <em>not-yet-peer-reviewed</em> study on monkeys showed immunity to the COVID-19 coronavirus for at least 28 days.<sup id="fnref39"><a href="#fn39" rel="footnote">39</a></sup></li>
</ul>
<p>The coronavirus responsible for COVID-19 is most closely related to the coronavirus responsible for SARS. SARS (probably) gave its survivors around 2 years of immunity.<sup id="fnref35"><a href="#fn35" rel="footnote">35</a></sup> The coronaviruses that cause &quot;the&quot; common cold give you 1 year of immunity<sup id="fnref36"><a href="#fn36" rel="footnote">36</a></sup>. So:</p>
<p>But for COVID-19 <em>in humans</em>, as of May 1st 2020, &quot;how long&quot; is the big unknown.</p>
<p><em>What if COVID-19 immunity doesn&#39;t last?</em></p>
<p>Here&#39;s a simulation starting with 100% <icon i></icon>, exponentially decaying into <icon r></icon>s after 10 days... but then back to susceptible, no-immunity <icon s></icon>s after 1 year:</p>
<p>For these simulations, let&#39;s say it&#39;s 1 year.
<strong>Here&#39;s a simulation starting with 100% <icon r></icon></strong>, exponentially decaying into susceptible, no-immunity <icon s></icon>s after 1 year, on <em>average</em>:</p>
<div class="sim">
<iframe src="sim?stage=yrs-1" width="800" height="540"></iframe>
<iframe src="sim?stage=yrs-1&format=lines&height=600" width="800" height="600"></iframe>
</div>
<p>Return of the exponential decay!</p>
@ -523,13 +549,13 @@
<p><img src="pics/seirs.png" alt=""></p>
<p>Now let&#39;s simulate a COVID-19 outbreak, over 10 years, with no interventions... <em>if immunity only lasts a year:</em></p>
<p>Now, let&#39;s simulate a COVID-19 outbreak, over 10 years, with no interventions... <em>if immunity only lasts a year:</em></p>
<div class="sim">
<iframe src="sim?stage=yrs-2&format=lines&height=600" width="800" height="600"></iframe>
</div>
<p>Previously, we only had <em>one</em> ICU-overwhelming spike. Now, we have several, <em>and</em> <icon i></icon> cases come to a rest <em>permanently at</em> ICU capacity. (Which, remember, we <em>tripled</em> for these simulations)</p>
<p>In previous simulations, we only had <em>one</em> ICU-overwhelming spike. Now, we have several, <em>and</em> <icon i></icon> cases come to a rest <em>permanently at</em> ICU capacity. (Which, remember, we <em>tripled</em> for these simulations)</p>
<p>R = 1, it&#39;s <strong>endemic.</strong></p>
@ -555,15 +581,15 @@
<p>What if there&#39;s no vaccine for <em>years</em>? Or <em>ever?</em></p>
<p><strong>To be clear: this is unlikely.</strong> Sure, there&#39;s never been a vaccine for any of the other coronaviruses before, but that&#39;s because SARS was eradicated quickly, and &quot;the&quot; common cold wasn&#39;t worth the investment. Coronaviruses aren&#39;t any more complex than the viruses we already have vaccines for, so most infectious disease researchers expect a vaccine in 1 to 2 years.</p>
<p><strong>To be clear: this is unlikely.</strong> Most epidemiologists expect a vaccine in 1 to 2 years. Sure, there&#39;s never been a vaccine for any of the other coronaviruses before, but that&#39;s because SARS was eradicated quickly, and &quot;the&quot; common cold wasn&#39;t worth the investment. </p>
<p>Still, they&#39;ve expressed worries about a vaccine: What if we can&#39;t make enough?<sup id="fnref37"><a href="#fn37" rel="footnote">37</a></sup> What if we rush it, and it&#39;s not safe?<sup id="fnref38"><a href="#fn38" rel="footnote">38</a></sup></p>
<p>Still, infectious disease researchers have expressed worries: What if we can&#39;t make enough?<sup id="fnref40"><a href="#fn40" rel="footnote">40</a></sup> What if we rush it, and it&#39;s not safe?<sup id="fnref41"><a href="#fn41" rel="footnote">41</a></sup></p>
<p>Even in the nightmare &quot;no-vaccine&quot; scenario, we still have 3 ways out. From most to least terrible:</p>
<p>1) Do intermittent or loose R &lt; 1 interventions, to reach &quot;natural herd immunity&quot;. (Warning: this will result in many deaths &amp; damaged lungs. <em>And</em> won&#39;t work if immunity doesn&#39;t last.)</p>
<p>2) Do the R &lt; 1 interventions forever. Contact tracing &amp; wearing masks just becomes a new norm in the post-COVID-19 world, like how STI tests &amp; wearing condoms became a new norm in the post-HIV world. (Nobody suggested &quot;herd immunity&quot; for HIV...)</p>
<p>2) Do the R &lt; 1 interventions forever. Contact tracing &amp; wearing masks just becomes a new norm in the post-COVID-19 world, like how STI tests &amp; wearing condoms became a new norm in the post-HIV world.</p>
<p>3) Do the R &lt; 1 interventions until we develop treatments that make COVID-19 way, way less likely to need critical care. (Which we should be doing <em>anyway!</em>) Reducing ICU use by 10x is the same as increasing our ICU capacity by 10x:</p>
@ -581,8 +607,6 @@
<p><strong>Here&#39;s an (optional) Sandbox Mode, with <em>everything</em> available. Simulate &amp; play around to your heart&#39;s content:</strong></p>
<p>[TODO: EMBED THIS IN A WAY THAT DOESN&#39;T SUCK]</p>
<div class="sim">
<iframe src="sim?stage=SB&format=sb&height=1000" width="800" height="1000"></iframe>
</div>
@ -597,7 +621,7 @@
</div>
</div>
<p>Plane&#39;s in the ocean. We&#39;ve scrambled onto the life rafts. It&#39;s time to find dry land.<sup id="fnref39"><a href="#fn39" rel="footnote">39</a></sup></p>
<p>Plane&#39;s sunk. We&#39;ve scrambled onto the life rafts. It&#39;s time to find dry land.<sup id="fnref42"><a href="#fn42" rel="footnote">42</a></sup></p>
<p>Teams of epidemiologists and policymakers (<a href="https://www.americanprogress.org/issues/healthcare/news/2020/04/03/482613/national-state-plan-end-coronavirus-crisis/">left</a>, <a href="https://www.aei.org/research-products/report/national-coronavirus-response-a-road-map-to-reopening/">right</a>, and <a href="https://ethics.harvard.edu/covid-roadmap">multi-partisan</a>) have come to a consensus on how to beat COVID-19, while protecting our lives <em>and</em> liberties.</p>
@ -617,353 +641,222 @@
<p>The only thing to fear is the idea that the only thing to fear is fear itself.</p>
<p><strong>{ Please let me know what you think! How did it feel overall, any parts in particular that went too slow or were too confusing, factual inaccuracies, nuances I missed, stuff I oughta mention, etc. Thank you! }</strong></p>
<p><strong>[ If you&#39;d like, please give me feedback on the Patreon comments! Don&#39;t share this yet, it&#39;ll go live tomorrow May 1st noon Eastern time. Thank you so much! 💖 ]</strong></p>
<div class="footnotes">
<hr>
<ol>
<li id="fn1">
<p>(NOTE: This guide was published on April 30th, 2020. Many details will become outdated, but Epidemiology 101 will remain true, and we&#39;re confident this guide will cover 95% of possible futures.)&nbsp;<a href="#fnref1" rev="footnote">&#8617;</a></p>
<p>NOTE: This guide was published on May 1st, 2020. Many details will become outdated, but Epidemiology 101 will remain true, and we&#39;re confident this guide will cover 95% of possible futures!&nbsp;<a href="#fnref1" rev="footnote">&#8617;</a></p>
</li>
<li id="fn2">
<p>https://wwwnc.cdc.gov/eid/article/26/6/20-0357_article&nbsp;<a href="#fnref2" rev="footnote">&#8617;</a></p>
<p>“The mean [serial] interval was 3.96 days (95% CI 3.534.39 days)”. <a href="https://wwwnc.cdc.gov/eid/article/26/6/20-0357_article">Du Z, Xu X, Wu Y, Wang L, Cowling BJ, Ancel Meyers L</a> (Disclaimer: Early release articles are not considered as final versions)&nbsp;<a href="#fnref2" rev="footnote">&#8617;</a></p>
</li>
<li id="fn3">
<p>source&nbsp;<a href="#fnref3" rev="footnote">&#8617;</a></p>
<p><strong>Remember: all these simulations are super simplified, for educational purposes.</strong>&nbsp;<a href="#fnref3" rev="footnote">&#8617;</a></p>
<p>One simplification: When you tell this simulation &quot;Infect 1 new person every X days&quot;, it&#39;s actually increasing # of infected by 1/X each day. Same for future settings in these simulations &quot;Recover every X days&quot; is actually reducing # of infected by 1/X each day.</p>
<p>Those <em>aren&#39;t</em> exactly the same, but it&#39;s close enough, and for educational purposes it&#39;s less opaque than setting the transmission/recovery rates directly.</p>
</li>
<li id="fn4">
<p>https://link.springer.com/article/10.1007/s11427-020-1661-4&nbsp;<a href="#fnref4" rev="footnote">&#8617;</a></p>
<p>“The median communicable period [...] was 9.5 days.” <a href="https://link.springer.com/article/10.1007/s11427-020-1661-4">Hu, Z., Song, C., Xu, C. et al</a> Yes, we know &quot;median&quot; is not the same as &quot;average&quot;. For simplified educational purposes, close enough.&nbsp;<a href="#fnref4" rev="footnote">&#8617;</a></p>
</li>
<li id="fn5">
<p>source, and sidenote on &#39;infectious&#39;&nbsp;<a href="#fnref5" rev="footnote">&#8617;</a></p>
<p>For more technical explanations of the SIR Model, see <a href="https://www.idmod.org/docs/hiv/model-sir.html#">the Institute for Disease Modeling</a> and <a href="https://en.wikipedia.org/wiki/Compartmental_models_in_epidemiology#The_SIR_model">Wikipedia</a>&nbsp;<a href="#fnref5" rev="footnote">&#8617;</a></p>
</li>
<li id="fn6">
<p>source&nbsp;<a href="#fnref6" rev="footnote">&#8617;</a></p>
<p>For more technical explanations of the SEIR Model, see <a href="https://www.idmod.org/docs/hiv/model-seir.html">the Institute for Disease Modeling</a> and <a href="https://en.wikipedia.org/wiki/Compartmental_models_in_epidemiology#The_SEIR_model">Wikipedia</a>&nbsp;<a href="#fnref6" rev="footnote">&#8617;</a></p>
</li>
<li id="fn7">
<p>source&nbsp;<a href="#fnref7" rev="footnote">&#8617;</a></p>
<p>“Assuming an incubation period distribution of mean 5.2 days from a separate study of early COVID-19 cases, we inferred that infectiousness started from 2.3 days (95% CI, 0.83.0 days) before symptom onset” (translation: Assuming symptoms start at 5 days, infectiousness starts 2 days before = Infectiousness starts at 3 days) <a href="https://www.nature.com/articles/s41591-020-0869-5">He, X., Lau, E.H.Y., Wu, P. et al.</a>&nbsp;<a href="#fnref7" rev="footnote">&#8617;</a></p>
</li>
<li id="fn8">
<p>https://bmcinfectdis.biomedcentral.com/articles/10.1186/1471-2334-14-480&nbsp;<a href="#fnref8" rev="footnote">&#8617;</a></p>
<p>“The median R value for seasonal influenza was 1.28 (IQR: 1.191.37)” <a href="https://bmcinfectdis.biomedcentral.com/articles/10.1186/1471-2334-14-480">Biggerstaff, M., Cauchemez, S., Reed, C. et al.</a>&nbsp;<a href="#fnref8" rev="footnote">&#8617;</a></p>
</li>
<li id="fn9">
<p>https://pubmed.ncbi.nlm.nih.gov/31995857/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7001239/&nbsp;<a href="#fnref9" rev="footnote">&#8617;</a></p>
<p>“We estimated the basic reproduction number R0 of 2019-nCoV to be around 2.2 (90% high density interval: 1.43.8)” <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7001239/">Riou J, Althaus CL.</a>&nbsp;<a href="#fnref9" rev="footnote">&#8617;</a></p>
</li>
<li id="fn10">
<p>https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article&nbsp;<a href="#fnref10" rev="footnote">&#8617;</a></p>
<p>“we calculated a median R0 value of 5.7 (95% CI 3.88.9)” <a href="https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article">Sanche S, Lin YT, Xu C, Romero-Severson E, Hengartner N, Ke R.</a>&nbsp;<a href="#fnref10" rev="footnote">&#8617;</a></p>
</li>
<li id="fn11">
<p>sas&nbsp;<a href="#fnref11" rev="footnote">&#8617;</a></p>
<p>This is pretending that you&#39;re equally infectious all throughout your &quot;infectious period&quot;. Again, simplifications for educational purposes.&nbsp;<a href="#fnref11" rev="footnote">&#8617;</a></p>
</li>
<li id="fn12">
<p>exact formula...&nbsp;<a href="#fnref12" rev="footnote">&#8617;</a></p>
<p>Remember R = R<sub>0</sub> * the ratio of transmissions still allowed. Remember also that ratio of transmissions allowed = 1 - ratio of transmissions <em>stopped</em>.&nbsp;<a href="#fnref12" rev="footnote">&#8617;</a></p>
<p>Therefore, to get R &lt; 1, you need to get R<sub>0</sub> * TransmissionsAllowed &lt; 1. </p>
<p>Therefore, TransmissionsAllowed &lt; 1/R<sub>0</sub></p>
<p>Therefore, 1 - TransmissionsStopped &lt; 1/R<sub>0</sub></p>
<p>Therefore, TransmissionsStopped &gt; 1 - 1/R<sub>0</sub></p>
<p>Therefore, you need to stop more than <strong>1 - 1/R<sub>0</sub></strong> of transmissions to get R &lt; 1 and contain the virus!</p>
</li>
<li id="fn13">
<p>https://www.statista.com/statistics/1105420/covid-icu-admission-rates-us-by-age-group/ Lower end, 5%.&nbsp;<a href="#fnref13" rev="footnote">&#8617;</a></p>
<p><a href="https://www.statista.com/statistics/1105420/covid-icu-admission-rates-us-by-age-group/">&quot;Percentage of COVID-19 cases in the United States from February 12 to March 16, 2020 that required intensive care unit (ICU) admission, by age group&quot;</a>. Between 4.9% to 11.5% of <em>all</em> COVID-19 cases required ICU. Generously picking the lower range, that&#39;s 5% or 1 in 20. Note that this total is specific to the US&#39;s age structure, and will be higher in countries with older populations, lower in countries with younger populations.&nbsp;<a href="#fnref13" rev="footnote">&#8617;</a></p>
</li>
<li id="fn14">
<p>https://sccm.org/Blog/March-2020/United-States-Resource-Availability-for-COVID-19&nbsp;<a href="#fnref14" rev="footnote">&#8617;</a></p>
<p>“Number of ICU beds = 96,596”. From <a href="https://sccm.org/Blog/March-2020/United-States-Resource-Availability-for-COVID-19">the Society of Critical Care Medicine</a> USA Population was 328,200,000 in 2019. 96,596 out of 328,200,000 = roughly 1 in 3400. &nbsp;<a href="#fnref14" rev="footnote">&#8617;</a></p>
</li>
<li id="fn15">
<p>https://www.theatlantic.com/health/archive/2020/03/coronavirus-pandemic-herd-immunity-uk-boris-johnson/608065/&nbsp;<a href="#fnref15" rev="footnote">&#8617;</a></p>
<p>“[Graham Medley] says that the actual goal is the same as that of other countries: flatten the curve by staggering the onset of infections. As a consequence, the nation may achieve herd immunity; its a side effect, not an aim. [...]&nbsp;<a href="#fnref15" rev="footnote">&#8617;</a></p>
<p>The governments actual coronavirus action plan, available online, doesnt mention herd immunity at all. [...] “Its been a case of how not to communicate during an outbreak,” says Devi Sridhar, a public-health specialist at the University of Edinburgh.”</p>
<p>From a <a href="https://www.theatlantic.com/health/archive/2020/03/coronavirus-pandemic-herd-immunity-uk-boris-johnson/608065/">The Atlantic article by Ed Yong</a></p>
</li>
<li id="fn16">
<p>https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-3156.2006.01568.x&nbsp;<a href="#fnref16" rev="footnote">&#8617;</a></p>
<p>“All eight eligible studies reported that handwashing lowered risks of respiratory infection, with risk reductions ranging from 6% to 44% [pooled value 24% (95% CI 640%)].” We rounded up the pooled value to 25% in these simulations for simplicity. <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-3156.2006.01568.x">Rabie, T. and Curtis, V.</a> Note: as this meta-analysis points out, the quality of studies for handwashing (at least in high-income countries) are awful.&nbsp;<a href="#fnref16" rev="footnote">&#8617;</a></p>
</li>
<li id="fn17">
<p>https://cmmid.github.io/topics/covid19/comix-impact-of-physical-distance-measures-on-transmission-in-the-UK.html&nbsp;<a href="#fnref17" rev="footnote">&#8617;</a></p>
<p>“We found a 73% reduction in the average daily number of contacts observed per participant. This would be sufficient to reduce R0 from a value from 2.6 before the lockdown to 0.62 (0.37 - 0.89) during the lockdown”. We rounded it down to 70% in these simulations for simplicity. <a href="https://cmmid.github.io/topics/covid19/comix-impact-of-physical-distance-measures-on-transmission-in-the-UK.html">Jarvis and Zandvoort et al</a>&nbsp;<a href="#fnref17" rev="footnote">&#8617;</a></p>
</li>
<li id="fn18">
<p>log scale&nbsp;<a href="#fnref18" rev="footnote">&#8617;</a></p>
<p>This distortion would go away if we plotted R on a logarithmic scale... but then we&#39;d have to explain <em>logarithmic scales.</em>&nbsp;<a href="#fnref18" rev="footnote">&#8617;</a></p>
</li>
<li id="fn19">
<p>https://science.sciencemag.org/content/early/2020/04/14/science.abb5793?&nbsp;<a href="#fnref19" rev="footnote">&#8617;</a></p>
<p>“Absent other interventions, a key metric for the success of social distancing is whether critical care capacities are exceeded. To avoid this, prolonged or intermittent social distancing may be necessary into 2022.” <a href="https://science.sciencemag.org/content/early/2020/04/14/science.abb5793">Kissler and Tedijanto et al</a>&nbsp;<a href="#fnref19" rev="footnote">&#8617;</a></p>
</li>
<li id="fn20">
<p>https://journals.sagepub.com/doi/abs/10.1177/1745691614568352&nbsp;<a href="#fnref20" rev="footnote">&#8617;</a></p>
<p>See <a href="https://journals.sagepub.com/doi/abs/10.1177/1745691614568352">Figure 6 from Holt-Lunstad &amp; Smith 2010</a>. Of course, big disclaimer that they found a <em>correlation</em>. But unless you want to try randomly assigning people to be lonely for life, observational evidence is all you&#39;re gonna get.&nbsp;<a href="#fnref20" rev="footnote">&#8617;</a></p>
</li>
<li id="fn21">
<p>sources plz, esp for incubation period 5 days&nbsp;<a href="#fnref21" rev="footnote">&#8617;</a></p>
<p><strong>3 days on average to infectiousness:</strong> “Assuming an incubation period distribution of mean 5.2 days from a separate study of early COVID-19 cases, we inferred that infectiousness started from 2.3 days (95% CI, 0.83.0 days) before symptom onset” (translation: Assuming symptoms start at 5 days, infectiousness starts 2 days before = Infectiousness starts at 3 days) <a href="https://www.nature.com/articles/s41591-020-0869-5">He, X., Lau, E.H.Y., Wu, P. et al.</a> &nbsp;<a href="#fnref21" rev="footnote">&#8617;</a></p>
<p><strong>4 days on average to infecting someone else:</strong> “The mean [serial] interval was 3.96 days (95% CI 3.534.39 days)” <a href="https://wwwnc.cdc.gov/eid/article/26/6/20-0357_article">Du Z, Xu X, Wu Y, Wang L, Cowling BJ, Ancel Meyers L</a></p>
<p><strong>5 days on average to feeling symptoms:</strong> “The median incubation period was estimated to be 5.1 days (95% CI, 4.5 to 5.8 days)” <a href="https://annals.org/AIM/FULLARTICLE/2762808/INCUBATION-PERIOD-CORONAVIRUS-DISEASE-2019-COVID-19-FROM-PUBLICLY-REPORTED">Lauer SA, Grantz KH, Bi Q, et al</a></p>
</li>
<li id="fn22">
<p>https://www.nature.com/articles/s41591-020-0869-5&nbsp;<a href="#fnref22" rev="footnote">&#8617;</a></p>
<p>“We estimated that 44% (95% confidence interval, 2569%) of secondary cases were infected during the index cases presymptomatic stage” <a href="https://www.nature.com/articles/s41591-020-0869-5">He, X., Lau, E.H.Y., Wu, P. et al</a>&nbsp;<a href="#fnref22" rev="footnote">&#8617;</a></p>
</li>
<li id="fn23">
<p>asds&nbsp;<a href="#fnref23" rev="footnote">&#8617;</a></p>
<p>“Contact tracing was a critical intervention in Liberia and represented one of the largest contact tracing efforts during an epidemic in history.” <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6152989/">Swanson KC, Altare C, Wesseh CS, et al.</a>&nbsp;<a href="#fnref23" rev="footnote">&#8617;</a></p>
</li>
<li id="fn24">
<p>https://science.sciencemag.org/content/early/2020/04/09/science.abb6936&nbsp;<a href="#fnref24" rev="footnote">&#8617;</a></p>
<p><a href="https://github.com/TCNCoalition/TCN#tcn-protocol">Temporary Contact Numbers, a decentralized, privacy-first contact tracing protocol</a>&nbsp;<a href="#fnref24" rev="footnote">&#8617;</a></p>
</li>
<li id="fn25">
<p>incoming&nbsp;<a href="#fnref25" rev="footnote">&#8617;</a></p>
<p><a href="https://pact.mit.edu/">PACT: Private Automated Contact Tracing</a>&nbsp;<a href="#fnref25" rev="footnote">&#8617;</a></p>
</li>
<li id="fn26">
<p>outgoing_aerosols&nbsp;<a href="#fnref26" rev="footnote">&#8617;</a></p>
<p><a href="https://www.apple.com/ca/newsroom/2020/04/apple-and-google-partner-on-covid-19-contact-tracing-technology/">Apple and Google partner on COVID-19 contact tracing technology </a>. Note they&#39;re not making the apps <em>themselves</em>, just creating the systems that will <em>support</em> those apps.&nbsp;<a href="#fnref26" rev="footnote">&#8617;</a></p>
</li>
<li id="fn27">
<p>outgoing_droplets&nbsp;<a href="#fnref27" rev="footnote">&#8617;</a></p>
<p>Lots of news reports and honestly, many research papers did not distinguish between &quot;cases who showed no symptoms when we tested them&quot; (pre-symptomatic) and &quot;cases who showed no symptoms <em>ever</em>&quot; (true asymptomatic). The only way you could tell the difference is by following up with cases later.&nbsp;<a href="#fnref27" rev="footnote">&#8617;</a></p>
<p>Which is what <a href="https://wwwnc.cdc.gov/eid/article/26/8/20-1274_article">this study</a> did. (Disclaimer: &quot;Early release articles are not considered as final versions.&quot;) In a call center in South Korea that had a COVID-19 outbreak, &quot;only 4 (1.9%) remained asymptomatic within 14 days of quarantine, and none of their household contacts acquired secondary infections.&quot;</p>
<p>So that means &quot;true asymptomatics&quot; are rare, and catching the disease from a true asymptomatic may be even rarer!</p>
</li>
<li id="fn28">
<p>homemade&nbsp;<a href="#fnref28" rev="footnote">&#8617;</a></p>
<p>From the same Oxford study that first recommended apps to fight COVID-19: <a href="https://science.sciencemag.org/content/early/2020/04/09/science.abb6936/tab-figures-data">Luca Ferretti &amp; Chris Wymant et al</a> See Figure 2. Assuming R<sub>0</sub> = 2.0, they found that: &nbsp;<a href="#fnref28" rev="footnote">&#8617;</a></p>
<ul>
<li>Symptomatics contribute R = 0.8 (40%)</li>
<li>Pre-symptomatics contribute R = 0.9 (45%)</li>
<li>Asymptomatics contribute R = 0.1 (5%, though their model has uncertainty and it could be much lower)</li>
<li>Environmental stuff like doorknobs contribute R = 0.2 (10%)</li>
</ul>
<p>And add up the pre- &amp; a-symptomatic contacts (45% + 5%) and you get 50% of R!</p>
</li>
<li id="fn29">
<p>ss&nbsp;<a href="#fnref29" rev="footnote">&#8617;</a></p>
<p>“None of these surgical masks exhibited adequate filter performance and facial fit characteristics to be considered respiratory protection devices.” <a href="https://www.sciencedirect.com/science/article/pii/S0196655307007742">Tara Oberg &amp; Lisa M. Brosseau</a>&nbsp;<a href="#fnref29" rev="footnote">&#8617;</a></p>
</li>
<li id="fn30">
<p>That BMJ article&nbsp;<a href="#fnref30" rev="footnote">&#8617;</a></p>
<p>“The overall 3.4 fold reduction [70% reduction] in aerosol copy numbers we observed combined with a nearly complete elimination of large droplet spray demonstrated by Johnson et al. suggests that surgical masks worn by infected persons could have a clinically significant impact on transmission.” <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3591312/">Milton DK, Fabian MP, Cowling BJ, Grantham ML, McDevitt JJ</a>&nbsp;<a href="#fnref30" rev="footnote">&#8617;</a></p>
</li>
<li id="fn31">
<p>s&nbsp;<a href="#fnref31" rev="footnote">&#8617;</a></p>
<p>Any actual scientist who read that last sentence is probably laugh-crying right now. See: <a href="https://en.wikipedia.org/wiki/Data_dredging">p-hacking</a>, <a href="https://en.wikipedia.org/wiki/Replication_crisis">the replication crisis</a>)&nbsp;<a href="#fnref31" rev="footnote">&#8617;</a></p>
</li>
<li id="fn32">
<p>ss&nbsp;<a href="#fnref32" rev="footnote">&#8617;</a></p>
<p>“It is time to apply the precautionary principle” <a href="https://www.bmj.com/content/bmj/369/bmj.m1435.full.pdf">Trisha Greenhalgh et al [PDF]</a>&nbsp;<a href="#fnref32" rev="footnote">&#8617;</a></p>
</li>
<li id="fn33">
<p>s&nbsp;<a href="#fnref33" rev="footnote">&#8617;</a></p>
<p><a href="https://www.cambridge.org/core/journals/disaster-medicine-and-public-health-preparedness/article/testing-the-efficacy-of-homemade-masks-would-they-protect-in-an-influenza-pandemic/0921A05A69A9419C862FA2F35F819D55">Davies, A., Thompson, K., Giri, K., Kafatos, G., Walker, J., &amp; Bennett, A</a> See Table 1: a 100% cotton T-shirt has around 2/3 the filtration efficiency as a surgical mask, for the two bacterial aerosols they tested.&nbsp;<a href="#fnref33" rev="footnote">&#8617;</a></p>
</li>
<li id="fn34">
<p>https://papers.ssrn.com/sol3/Papers.cfm?abstract_id=3551767 The average R-value of these 100 cities is 1.83 , One-degree Celsius increase in temperature and one percent increase in relative humidity lower R by 0.0225 &nbsp;<a href="#fnref34" rev="footnote">&#8617;</a></p>
<p><strong>&quot;We need to save supplies for hospitals.&quot;</strong> <em>Absolutely agreed.</em> But that&#39;s more of an argument for increasing mask production, not rationing. In the meantime, we can make cloth masks.&nbsp;<a href="#fnref34" rev="footnote">&#8617;</a></p>
<p><strong>&quot;They&#39;re hard to wear correctly.&quot;</strong> It&#39;s also hard to wash your hands according to the WHO Guidelines seriously, &quot;Step 3) right palm over left dorsum&quot;?! but we still recommend handwashing, because imperfect is still better than nothing.</p>
<p><strong>&quot;It&#39;ll make people more reckless with handwashing &amp; social distancing.&quot;</strong> Sure, and safety belts make people ignore stop signs, and flossing makes people eat rocks. But seriously, we&#39;d argue the opposite: masks are a <em>constant physical reminder</em> to be careful and in East Asia, masks are also a symbol of solidarity!</p>
</li>
<li id="fn35">
<p>https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/&nbsp;<a href="#fnref35" rev="footnote">&#8617;</a></p>
<p>“One-degree Celsius increase in temperature [...] lower[s] R by 0.0225” and “The average R-value of these 100 cities is 1.83”. 0.0225 ÷ 1.83 = ~1.2%. <a href="https://papers.ssrn.com/sol3/Papers.cfm?abstract_id=3551767">Wang, Jingyuan and Tang, Ke and Feng, Kai and Lv, Weifeng</a>&nbsp;<a href="#fnref35" rev="footnote">&#8617;</a></p>
</li>
<li id="fn36">
<p>https://pubmed.ncbi.nlm.nih.gov/2170159/&nbsp;<a href="#fnref36" rev="footnote">&#8617;</a></p>
<p>“SARS-specific antibodies were maintained for an average of 2 years [...] Thus, SARS patients might be susceptible to reinfection ≥3 years after initial exposure.” <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/">Wu LP, Wang NC, Chang YH, et al.</a> &quot;Sadly&quot; we&#39;ll never know how long SARS immunity would have really lasted, since we eradicated it so quickly.&nbsp;<a href="#fnref36" rev="footnote">&#8617;</a></p>
</li>
<li id="fn37">
<p>https://www.nature.com/articles/d41586-020-01063-8&nbsp;<a href="#fnref37" rev="footnote">&#8617;</a></p>
<p>“We found no significant difference between the probability of testing positive at least once and the probability of a recurrence for the beta-coronaviruses HKU1 and OC43 at 34 weeks after enrollment/first infection.” <a href="http://www.columbia.edu/%7Ejls106/galanti_shaman_ms_supp.pdf">Marta Galanti &amp; Jeffrey Shaman (PDF)</a>&nbsp;<a href="#fnref37" rev="footnote">&#8617;</a></p>
</li>
<li id="fn38">
<p>https://www.nature.com/articles/d41586-020-00751-9&nbsp;<a href="#fnref38" rev="footnote">&#8617;</a></p>
<p>“Once a person fights off a virus, viral particles tend to linger for some time. These cannot cause infections, but they can trigger a positive test.” <a href="https://www.statnews.com/2020/04/20/everything-we-know-about-coronavirus-immunity-and-antibodies-and-plenty-we-still-dont/">from STAT News by Andrew Joseph</a>&nbsp;<a href="#fnref38" rev="footnote">&#8617;</a></p>
</li>
<li id="fn39">
<p>https://www.statnews.com/2020/04/01/navigating-covid-19-pandemic/&nbsp;<a href="#fnref39" rev="footnote">&#8617;</a></p>
<p>From <a href="https://www.biorxiv.org/content/10.1101/2020.03.13.990226v1.abstract">Bao et al.</a> <em>Disclaimer: This article is a preprint and has not been certified by peer review (yet).</em> Also, to emphasize: they only tested re-infection 28 days later. &nbsp;<a href="#fnref39" rev="footnote">&#8617;</a></p>
</li>
<li id="fn40">
<p>“If a coronavirus vaccine arrives, can the world make enough?” <a href="https://www.nature.com/articles/d41586-020-01063-8">by Roxanne Khamsi, on Nature</a>&nbsp;<a href="#fnref40" rev="footnote">&#8617;</a></p>
</li>
<li id="fn41">
<p>“Dont rush to deploy COVID-19 vaccines and drugs without sufficient safety guarantees” <a href="https://www.nature.com/articles/d41586-020-00751-9">by Shibo Jiang, on Nature</a>&nbsp;<a href="#fnref41" rev="footnote">&#8617;</a></p>
</li>
<li id="fn42">
<p>Dry land metaphor <a href="https://www.statnews.com/2020/04/01/navigating-covid-19-pandemic/">from Marc Lipsitch &amp; Yonatan Grad, on STAT News</a>&nbsp;<a href="#fnref42" rev="footnote">&#8617;</a></p>
</li>
</ol>
</div>
</article>
-->
<article>
<div class="section">
<div>
<h1>What Happens Next?</h1>
<h2>COVID-19 Futures, Explained With Playable Simulations</h2>
<h3>by Marcel Salathé (epidemiologist) and Nicky Case (art/code)</h3>
<h3>🕐 28 min play/read</h3>
</div>
</div>
<p>foo bar foo bar foo bar</p>
<p>foo bar foo bar foo bar</p>
<p>foo bar foo bar foo bar</p>
<p>foo bar foo bar foo bar</p>
<p>foo bar foo bar foo bar</p>
<p>foo bar foo bar foo bar</p>
<p>foo bar foo bar foo bar</p>
<p>foo bar foo bar foo bar</p>
<div class="footnotes">
<hr>
<ol>
<li id="fn1">
<p>(NOTE: This guide was published on April 30th, 2020. Many details will become outdated, but Epidemiology 101 will remain true, and we&#39;re confident this guide will cover 95% of possible futures.)&nbsp;<a href="#fnref1" rev="footnote">&#8617;</a></p>
</li>
<li id="fn2">
<p>https://wwwnc.cdc.gov/eid/article/26/6/20-0357_article&nbsp;<a href="#fnref2" rev="footnote">&#8617;</a></p>
</li>
<li id="fn3">
<p>source&nbsp;<a href="#fnref3" rev="footnote">&#8617;</a></p>
</li>
<li id="fn4">
<p>https://link.springer.com/article/10.1007/s11427-020-1661-4&nbsp;<a href="#fnref4" rev="footnote">&#8617;</a></p>
</li>
<li id="fn5">
<p>source, and sidenote on &#39;infectious&#39;&nbsp;<a href="#fnref5" rev="footnote">&#8617;</a></p>
</li>
<li id="fn6">
<p>source&nbsp;<a href="#fnref6" rev="footnote">&#8617;</a></p>
</li>
<li id="fn7">
<p>source&nbsp;<a href="#fnref7" rev="footnote">&#8617;</a></p>
</li>
<li id="fn8">
<p>https://bmcinfectdis.biomedcentral.com/articles/10.1186/1471-2334-14-480&nbsp;<a href="#fnref8" rev="footnote">&#8617;</a></p>
</li>
<li id="fn9">
<p>https://pubmed.ncbi.nlm.nih.gov/31995857/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7001239/&nbsp;<a href="#fnref9" rev="footnote">&#8617;</a></p>
</li>
<li id="fn10">
<p>https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article&nbsp;<a href="#fnref10" rev="footnote">&#8617;</a></p>
</li>
<li id="fn11">
<p>sas&nbsp;<a href="#fnref11" rev="footnote">&#8617;</a></p>
</li>
<li id="fn12">
<p>exact formula...&nbsp;<a href="#fnref12" rev="footnote">&#8617;</a></p>
</li>
<li id="fn13">
<p>https://www.statista.com/statistics/1105420/covid-icu-admission-rates-us-by-age-group/ Lower end, 5%.&nbsp;<a href="#fnref13" rev="footnote">&#8617;</a></p>
</li>
<li id="fn14">
<p>https://sccm.org/Blog/March-2020/United-States-Resource-Availability-for-COVID-19&nbsp;<a href="#fnref14" rev="footnote">&#8617;</a></p>
</li>
<li id="fn15">
<p>https://www.theatlantic.com/health/archive/2020/03/coronavirus-pandemic-herd-immunity-uk-boris-johnson/608065/&nbsp;<a href="#fnref15" rev="footnote">&#8617;</a></p>
</li>
<li id="fn16">
<p>https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-3156.2006.01568.x&nbsp;<a href="#fnref16" rev="footnote">&#8617;</a></p>
</li>
<li id="fn17">
<p>https://cmmid.github.io/topics/covid19/comix-impact-of-physical-distance-measures-on-transmission-in-the-UK.html&nbsp;<a href="#fnref17" rev="footnote">&#8617;</a></p>
</li>
<li id="fn18">
<p>log scale&nbsp;<a href="#fnref18" rev="footnote">&#8617;</a></p>
</li>
<li id="fn19">
<p>https://science.sciencemag.org/content/early/2020/04/14/science.abb5793?&nbsp;<a href="#fnref19" rev="footnote">&#8617;</a></p>
</li>
<li id="fn20">
<p>https://journals.sagepub.com/doi/abs/10.1177/1745691614568352&nbsp;<a href="#fnref20" rev="footnote">&#8617;</a></p>
</li>
<li id="fn21">
<p>sources plz, esp for incubation period 5 days&nbsp;<a href="#fnref21" rev="footnote">&#8617;</a></p>
</li>
<li id="fn22">
<p>https://www.nature.com/articles/s41591-020-0869-5&nbsp;<a href="#fnref22" rev="footnote">&#8617;</a></p>
</li>
<li id="fn23">
<p>asds&nbsp;<a href="#fnref23" rev="footnote">&#8617;</a></p>
</li>
<li id="fn24">
<p>https://science.sciencemag.org/content/early/2020/04/09/science.abb6936&nbsp;<a href="#fnref24" rev="footnote">&#8617;</a></p>
</li>
<li id="fn25">
<p>incoming&nbsp;<a href="#fnref25" rev="footnote">&#8617;</a></p>
</li>
<li id="fn26">
<p>outgoing_aerosols&nbsp;<a href="#fnref26" rev="footnote">&#8617;</a></p>
</li>
<li id="fn27">
<p>outgoing_droplets&nbsp;<a href="#fnref27" rev="footnote">&#8617;</a></p>
</li>
<li id="fn28">
<p>homemade&nbsp;<a href="#fnref28" rev="footnote">&#8617;</a></p>
</li>
<li id="fn29">
<p>ss&nbsp;<a href="#fnref29" rev="footnote">&#8617;</a></p>
</li>
<li id="fn30">
<p>That BMJ article&nbsp;<a href="#fnref30" rev="footnote">&#8617;</a></p>
</li>
<li id="fn31">
<p>s&nbsp;<a href="#fnref31" rev="footnote">&#8617;</a></p>
</li>
<li id="fn32">
<p>ss&nbsp;<a href="#fnref32" rev="footnote">&#8617;</a></p>
</li>
<li id="fn33">
<p>s&nbsp;<a href="#fnref33" rev="footnote">&#8617;</a></p>
</li>
<li id="fn34">
<p>https://papers.ssrn.com/sol3/Papers.cfm?abstract_id=3551767 The average R-value of these 100 cities is 1.83 , One-degree Celsius increase in temperature and one percent increase in relative humidity lower R by 0.0225 &nbsp;<a href="#fnref34" rev="footnote">&#8617;</a></p>
</li>
<li id="fn35">
<p>https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/&nbsp;<a href="#fnref35" rev="footnote">&#8617;</a></p>
</li>
<li id="fn36">
<p>https://pubmed.ncbi.nlm.nih.gov/2170159/&nbsp;<a href="#fnref36" rev="footnote">&#8617;</a></p>
</li>
<li id="fn37">
<p>https://www.nature.com/articles/d41586-020-01063-8&nbsp;<a href="#fnref37" rev="footnote">&#8617;</a></p>
</li>
<li id="fn38">
<p>https://www.nature.com/articles/d41586-020-00751-9&nbsp;<a href="#fnref38" rev="footnote">&#8617;</a></p>
</li>
<li id="fn39">
<p>https://www.statnews.com/2020/04/01/navigating-covid-19-pandemic/&nbsp;<a href="#fnref39" rev="footnote">&#8617;</a></p>
</li>
</ol>
</div>
</article>
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@ -191,7 +191,7 @@ sliderColors.push([ 'hospital', '#000' ]);
let hackStyle = '';
sliderColors.forEach((icPair, i)=>{
if(i==0) return;
//if(i==0) return;
let [name,color] = icPair;
@ -530,13 +530,7 @@ let draw = ()=>{
// R
y += h;
h = R * canvas.height;
ctx.fillStyle = "#cccccc";
ctx.fillRect(0,y,w,h);
// I
y += h;
h = I * canvas.height;
ctx.fillStyle = "#ff4040";
ctx.fillStyle = "#bbbbbb";
ctx.fillRect(0,y,w,h);
// E
@ -545,6 +539,12 @@ let draw = ()=>{
ctx.fillStyle = "#FF9393";
ctx.fillRect(0,y,w,h);
// I
y += h;
h = I * canvas.height;
ctx.fillStyle = "#ff4040";
ctx.fillRect(0,y,w,h);
// INTERVENTIONS
y = 0;
h = canvas.height;

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@ -12,11 +12,22 @@
<body>
<p><strong>{WIP, DON&#39;T SHARE YET THX!}</strong></p>
<div class="section">
<div>
<h1>What Happens Next?</h1>
<h2>COVID-19 Futures, Explained With Playable Simulations</h2>
<h3>by Marcel Salathé (epidemiologist) and Nicky Case (art/code)</h3>
<h3>🕐 28 min play/read</h3>
</div>
</div>
<p><strong>[ Hi early-access folks! Don&#39;t share this yet, I&#39;m still polishing it up. Once you&#39;re done please give feedback on the Patreon comments. I&#39;ll add you to the playtester credits if you want, thanks! ^_^ ]</strong></p>
<p>. . .</p>
<p>&quot;The only thing to fear is fear itself&quot; was stupid advice.</p>
<p>Sure, don&#39;t hoard toilet paper but if policymakers fear fear itself, they&#39;ll downplay dangers to us to avoid &quot;mass panic&quot;. Fear&#39;s not the problem, it&#39;s how we <em>channel</em> our fear. Fear gives us energy to deal with dangers now, and prepare for dangers later.</p>
<p>Sure, don&#39;t hoard toilet paper but if policymakers fear fear itself, they&#39;ll downplay real dangers to avoid &quot;mass panic&quot;. Fear&#39;s not the problem, it&#39;s how we <em>channel</em> our fear. Fear gives us energy to deal with dangers now, and prepare for dangers later.</p>
<p>Honestly, we (Marcel, epidemiologist + Nicky, art/code) are worried. We bet you are, too! That&#39;s why we&#39;ve channelled our fear into making these <strong>playable simulations</strong>, so that <em>you</em> can channel your fear into understanding:</p>
@ -26,7 +37,7 @@
<li><strong>The Next Few Years</strong> (loss of immunity? no vaccine?)</li>
</ul>
<p>This guide (published April 30th, 2020<sup id="fnref1"><a href="#fn1" rel="footnote">1</a></sup>) is meant to give you hope <em>and</em> fear. To beat COVID-19 <strong>in a way that also protects our mental &amp; financial health</strong>, we need optimism to create plans, and pessimism to create backup plans. As Gladys Bronwyn Stern once said, <em>“The optimist invents the airplane and the pessimist the parachute.”</em></p>
<p>This guide (published May 1st, 2020<sup id="fnref1"><a href="#fn1" rel="footnote">1</a></sup>) is meant to give you hope <em>and</em> fear. To beat COVID-19 <strong>in a way that also protects our mental &amp; financial health</strong>, we need optimism to create plans, and pessimism to create backup plans. As Gladys Bronwyn Stern once said, <em>“The optimist invents the airplane and the pessimist the parachute.”</em></p>
<p>So, buckle in: we&#39;re about to experience some turbulence.</p>
@ -40,13 +51,11 @@
<p><strong>Epidemiologists use epidemic simulators to learn how not to crash humanity.</strong></p>
<p>So, let&#39;s make a simple &quot;epidemic flight simulator&quot;! In this simulation, <icon i></icon> Infectious people can turn <icon s></icon> Susceptible people into more <icon i></icon> Infectious people:</p>
<p>So, let&#39;s make a very, <em>very</em> simple &quot;epidemic flight simulator&quot;! In this simulation, <icon i></icon> Infectious people can turn <icon s></icon> Susceptible people into more <icon i></icon> Infectious people:</p>
<p><img src="pics/spread.png" alt=""></p>
<p>It&#39;s estimated that, <em>at the start</em> of a COVID-19 outbreak, the virus jumps from an <icon i></icon> to an <icon s></icon> <em>approximately</em> every 4 days.<sup id="fnref2"><a href="#fn2" rel="footnote">2</a></sup></p>
<p>[TODO: Actually fill out source / footnotes]</p>
<p>It&#39;s estimated that, <em>at the start</em> of a COVID-19 outbreak, the virus jumps from an <icon i></icon> to an <icon s></icon> every 4 days, <em>on average</em>.<sup id="fnref2"><a href="#fn2" rel="footnote">2</a></sup> (remember, there&#39;s a lot of variation)</p>
<p>If we simulate &quot;double every 4 days&quot; <em>and nothing else</em>, on a population starting with just 0.001% <icon i></icon>, what happens? </p>