"The only thing to fear is fear itself" was stupid advice.
- -Sure, don't hoard toilet paper – but if policymakers fear fear itself, they'll downplay real dangers to avoid "mass panic". Fear's not the problem, it's how we channel our fear. Fear gives us energy to deal with dangers now, and prepare for dangers later.
- -Honestly, we (Marcel, epidemiologist + Nicky, art/code) are worried. We bet you are, too! That's why we've channelled our fear into making these playable simulations, so that you can channel your fear into understanding:
- --
-
- The Last Few Months (epidemiology 101, SEIR model, R & R0) -
- The Next Few Months (lockdowns, contact tracing, masks) -
- The Next Few Years (loss of immunity? no vaccine?) -
This guide (published May 1st, 2020. click this footnote!→1) is meant to give you hope and fear. To beat COVID-19 in a way that also protects our mental & financial health, we need optimism to create plans, and pessimism to create backup plans. As Gladys Bronwyn Stern once said, “The optimist invents the airplane and the pessimist the parachute.”
++ + Prevedle v slovenščino: Polona Kren · Barbara Pliberšek · Sanja Rajter + Predloge za izboljšave pošljite na info@databitlab.eu ali dianoia@um.si +
So, buckle in: we're about to experience some turbulence.
+“Edino česar se moramo bati, je strahu samega!” je bil neumen nasvet.
+Seveda, ne delajte si zalog toaletnega papirja – ampak, če se politiki sami bojijo strahu, bodo zmanjšali pomen resnične nevarnosti in se izognili “množični paniki”. Strah ni problem. Problem je kam preusmerimo svoj strah.
+Strah nam daje energijo, da se soočimo z nevarnostmi, in se pripravimo na vse nevarnosti, ki še prihajajo.
Iskreno, midva (Marcel, epidemolog + Nicky, razvijalec videoiger) sva v skrbeh. Staviva, da ste tudi vi! Zato sva usmerila najin strah v izvedbo teh igrivih simulacij, da lahko tudi vi usmerite svoj strah v razumevanje:
+-
+
- Zadnjih nekaj mesecev (Uvod v epidemiologijo, model SEIR, R & R0) +
- Naslednjih nekaj mesecev (karantena, sledenje stikov, maske) +
- Naslednjih nekaj let (padec imunskega sistema?, neobstoj cepiva?) +
Ta vodič (objavljeno 1. 5. 2020, kliknite za opombo!→[1]) bi vam naj dal upanje in strah, da premagate COVID-19 na način, ki ščiti naše duševno in fizično zdravje. Optimizem potrebujemo za ustvarjanje načrtov, za pripravo rezervnih načrtov pa potrebujemo pesimizem.
+Kot je nekoč rekel Gladys Bronwyn, “Optimist si izmisli letalo, pesimist pa padalo.”
Torej, pripnite se, kmalu bomo doživeli nekaj turbulenc!
- Pilots use flight simulators to learn how not to crash planes.
- -Epidemiologists use epidemic simulators to learn how not to crash humanity.
- -So, let's make a very, very simple "epidemic flight simulator"! In this simulation,
It's estimated that, at the start of a COVID-19 outbreak, the virus jumps from an
If we simulate "double every 4 days" and nothing else, on a population starting with just 0.001%
Click "Start" to play the simulation! You can re-play it later with different settings: (technical caveats: 3)
- -
+ Piloti uporabljajo simulatorje letenja, da se naučijo, kako leteti, da ne bi strmoglavili letal.
+Epidemiologi uporabljajo simulatorje epidemij, da se naučijo, kako ne bi strmoglavili človeštva.
+Torej, naredimo zelo, zelo preprost “simulator epidemije letenja”! V tej simulaciji lahko
Ocenjuje se, da na začetku izbruha COVID-19, v povprečju virus skoči z
Če v populaciji, ki ima v začetku samo 0,001% okuženih, dodamo simulacijo "podvoji vsake 4 dni" in nič druga, kaj se zgodi?
+Pritisni “Začetek” za predvajanje simulacije! Kasneje lahko ponoviš z drugačnimi nastavitvami (tehnična opozorila [3]):
+This is the exponential growth curve. Starts small, then explodes. "Oh it's just a flu" to "Oh right, flus don't create mass graves in rich cities".
- -
But, this simulation is wrong. Exponential growth, thankfully, can't go on forever. One thing that stops a virus from spreading is if others already have the virus:
- -
The more
How's this change the growth of an epidemic? Let's find out:
- -To je eksponentna krivulja. Najprej narašča zelo počasi in nato eksplodira. “Ah, to je samo gripa,” do "Ojoj, gripa ne bi smela ustvarjati množičnih grobišč v mestih."
+
+Ampak ta simulacija je napačna, saj se na srečo ekponentna
+rast ne more odvijati v neskončnost.
+Ena od omejitev širjenja virusa je tudi, da se ne more širiti, če
+so vsi že okuženi:
Več
Kako to vpliva na rast epidemije? +Odgovor se skriva v naslednjih vrsticah:
+To je logistična krivulja rasti v obliki črke S. Sprva raste počasi, eksplodira in se spet upočasni.
+Ampak ta simulacija je še vedno napačna.
+Ne upoštevamo dejstva, da
Poenostavimo, da so si vsi
+Pretvarjajmo se, da se
Pri COVID-19 je predvideno, da si v povprečju
-
This is the "S-shaped" logistic growth curve. Starts small, explodes, then slows down again.
- -But, this simulation is still wrong. We're missing the fact that
For simplicity's sake, let's pretend that all
With COVID-19, it's estimated you're
This is the opposite of exponential growth, the exponential decay curve.
- -Now, what happens if you simulate S-shaped logistic growth with recovery?
- -
Let's find out.
- -Red curve is current cases
- Gray curve is total cases (current + recovered
To je ravno nasprotje eksponentne rastoče krivulje, to je eksponentno padajoča krivulja.
+Kaj se zgodi, če simuliramo logistično krivuljo rasti v obliki črke S in upoštevamo, da si ljudje opomorejo?
+
Pa ugotovimo…
+Rdeča krivulja so trenutni primeri
+Siva krivulja so vsi primeri (trenutni + opomogli
And that's where that famous curve comes from! It's not a bell curve, it's not even a "log-normal" curve. It has no name. But you've seen it a zillion times, and beseeched to flatten.
- -This is the the SIR Model,5
- (
- the second-most important idea in Epidemiology 101:
NOTE: The simulations that inform policy are way, way more sophisticated than this! But the SIR Model can still explain the same general findings, even if missing the nuances.
- -Actually, let's add one more nuance: before an
(This variant is called the SEIR Model6, where the "E" stands for
For COVID-19, it's estimated that you're
Red + Pink curve is current cases (infectious
- Gray curve is total cases (current + recovered
In tako pridemo do najbolj znane krivulje!
+To ni normalna porazdelitev, niti ni “logaritemsko normalna”. Krivulja nima imena, vendar ste jo že videli neštetokrat.
To je model SIR,[5]
+(
+Druga-najbolj pomembna ugotovitev v Uvodu v epidemiologijo:
Opomba: Simulacije, ki obveščajo politike, so precej, precej bolj zapletene od tega! +Ampak model SIR še vedno pojasni glavne rezultate, čeprav so izpuščene podrobnosti.
+Pravzaprav, dodajmo še en detajl: preden
(To različico imenujemo model SEIR[6], kjer je “E” okrajšava za
+Za COVID-19 ocenjujemo, da ste v povprečju
Rdeča + Roza krivulja so trenutni primeri (okuženi
Not much changes! How long you stay
Why's that? Because of the first-most important idea in Epidemiology 101:
- -
Short for "Reproduction number". It's the average number of people an
R changes over the course of an outbreak, as we get more immunity & interventions.
- -R0 (pronounced R-nought) is what R is at the start of an outbreak, before immunity or interventions. R0 more closely reflects the power of the virus itself, but it still changes from place to place. For example, R0 is higher in dense cities than sparse rural areas.
- -(Most news articles – and even some research papers! – confuse R and R0. Again, science terminology is bad)
- -The R0 for "the" seasonal flu is around 1.288. This means, at the start of a flu outbreak, each
The R0 for COVID-19 is estimated to be around 2.2,9 though one not-yet-finalized study estimates it was 5.7(!) in Wuhan.10
- -In our simulations – at the start & on average – an
Play with this R0 calculator, to see how R0 depends on recovery time & new-infection time:
- -Ni se veliko spremenilo! Kako dolgo si
Zakaj je tako? Zaradi prve-najpomemnejše ugotovitve v Uvodu v epidemiologijo:
+
R je kratica, s katero označimo “dejansko reprodukcijsko število”. Predstavlja povprečno število ljudi, ki jih en bolnik v neki populaciji okuži, preden ozdravi ali umre.
+
R se med izbruhom spreminja, saj sčasoma pridobimo imunost in sprejmemo ustrezne ukrepe.
+R0 (izgovarjamo R-nič) predstavlja R na začetku izbruha, torej pred imunostjo in ukrepi. R0 natančneje odraža moč virusa, vendar se le-ta še vedno spreminja od mesta do mesta. Na primer: R0 je višji v gosteje naseljenih mestih kakor v redkih podeželskih območjih.
+(V večini novic, celo v nekaterih raziskovalnih člankih, pride do zmede zaradi zamenjave R in R0. Znova je potrebno poudariti, da smo pri uporabi znanstvene terminologije zares nedosledni.)
+R0 za t.i. »sezonsko gripo« znaša približno 1,28[8]. To pomeni, da na začetku izbruha gripe vsak
Predvideva se, da bo vrednost R0 za COVID-19 znašala približno 2,2,[9] vendar sicer še nedokončana študija v Wuhanu omenja vrednost 5,7![10]
+V naših simulacijah oseba na začetku v povprečju okuži nekoga drugega vsake 4 dni ter to počne več kot 10 dni. “4 dnevi” grejo v “10 dni” dva in pol krat. To pomeni, da vsaka oseba na začetku v povprečju okuži 2,5 drugih oseb. Zato je potemtakem R0 = 2,5. (opozorila: [11])
+Preizkusi R0 kalkulator, ki prikazuje, kako R0 vpliva na čas zdravljenja in čas, v katerem pride do nove infekcije:
+
But remember, the fewer
Ne pozabite, manj kot je
When enough people have immunity, R < 1, and the virus is contained! This is called herd immunity. For flus, herd immunity is achieved with a vaccine. Trying to achieve "natural herd immunity" by letting folks get infected is a terrible idea. (But not for the reason you may think! We'll explain later.)
- -Now, let's play the SEIR Model again, but showing R0, R over time, and the herd immunity threshold:
- -Ko je dovolj ljudi imunih, je R < 1 in virus je moč obvladovati! Temu pravimo čredna imunost. Čredno imunost pri gripi dosežemo s cepivom. Ideja o tem, da bi “naravno imunost črede” dosegli tako, da bi se ljudje okužili, je grozljiva. (Vendar ne iz razloga, za katerega morda mislite! Pojasnilo sledi kasneje.)
+Znova uporabimo Model SEIR, vendar sedaj prikažimo R0, R skozi čas in mejo čredne imunosti:
+
NOTE: Total cases does not stop at herd immunity, but overshoots it! And it crosses the threshold exactly when current cases peak. (This happens no matter how you change the settings – try it for yourself!)
- -This is because when there are more non-
If there's only one lesson you take away from this guide, here it is – it's an extremely complex diagram so please take time to fully absorb it:
- -
This means: we do NOT need to catch all transmissions, or even nearly all transmissions, to stop COVID-19!
- -It's a paradox. COVID-19 is extremely contagious, yet to contain it, we "only" need to stop more than 60% of infections. 60%?! If that was a school grade, that's a D-. But if R0 = 2.5, cutting that by 61% gives us R = 0.975, which is R < 1, virus is contained! (exact formula:12)
- -
(If you think R0 or the other numbers in our simulations are too low/high, that's good you're challenging our assumptions! There'll be a "Sandbox Mode" at the end of this guide, where you can plug in your own numbers, and simulate what happens.)
- -Every COVID-19 intervention you've heard of – handwashing, social/physical distancing, lockdowns, self-isolation, contact tracing & quarantining, face masks, even "herd immunity" – they're all doing the same thing:
- -Getting R < 1.
- -So now, let's use our "epidemic flight simulator" to figure this out: How can we get R < 1 in a way that also protects our mental health and financial health?
- -Brace yourselves for an emergency landing...
+POZOR: Število vseh okužb se ne ustavi pri čredni imunosti, ampak jo preseže! Presežejo jo natanko tedaj, ko je število dnevnih novih okužb najvišje. (To se zgodi ne glede na izbrane parametre – poskusite sami!)
+Razlog je, da pri čredni imunosti nastopi R < 1 in število novih okužb začne upadati.
+Če boste iz tega članka odnesli le eno lekcijo, je to sledeča - pred vami je izredno zapleten diagram, zato si prosim vzemite čas, da ga boste popolnoma razumeli:
+
To pomeni: za zaustavitev COVID-19 nam NI potrebno preprečiti večine, kaj šele vseh prenosov!
+To je paradoks. COVID-19 je izjemno nalezljiv, kljub temu pa moramo ustaviti “le” nekaj več kot 60% okužb. 60% ?! Če bi bila to šolska ocena, je to zadostno (2). Če pa je R0 = 2,5, sledi, da za 61% zmanjšamo R = 0,975. Potem je R < 1 in virus je obvladljiv, saj je tako rekoč omejen! (Natančna formula: [12])
+
(Če menite, da so R0 ali druge številke v naših simulacijah prenizke/previsoke, je to odlično, saj tako izpodbijate naše predpostavke! Na koncu tega članka bo na voljo “način peskovnika”, kjer lahko priključite svoje številke in simulirate, kaj se zgodi.)
+Vsak ukrep glede COVID-19 za katerega ste slišali - pranje rok, socialno/fizično distanciranje, zaprtja, samoizolacija, sledenje stikom in karantena, maske za obraz, celo “imunost črede” - vsi počnejo popolnoma isto:
+Prispevajo k R < 1.
+Sedaj uporabimo naš “simulator letenja za epidemijo”, da ugotovimo sledeče: Kako lahko dobimo R < 1 na način, ki ščiti tudi naše duševno in finančno zdravje?
+Pripravite se na zasilni pristanek…
- ...could have been worse. Here's a parallel universe we avoided:
- -Scenario 0: Do Absolutely Nothing
- -Around 1 in 20 people infected with COVID-19 need to go to an ICU (Intensive Care Unit).13 In a rich country like the USA, there's 1 ICU bed per 3400 people.14 Therefore, the USA can handle 20 out of 3400 people being simultaneously infected – or, 0.6% of the population.
- -Even if we more than tripled that capacity to 2%, here's what would've happened if we did absolutely nothing:
+
+ …lahko bi bilo huje. V nadaljevanju sledi prikaz vzporednega sveta, kateremu smo se uspeli izogniti:
+Scenarij 0: Ne naredimo popolnoma nič
+Približno eden izmed 20 ljudi, ki so okuženi s COVID-19, se mora odpraviti na oddelek za intenzivno nego.[13] V bogatih državah, kot so na primer ZDA, 1 oddelek za intenzivno nego premore le 1 ležišče za kar 3400 ljudi.[14] Zato lahko ZDA hkrati sprejmejo le 20 izmed 3400 okuženih ljudi – oziroma 0,6% prebivalstva.
+Tudi če bi to vrednost več kot potrojili na 2%, nam spodnja simulacija prikazuje, kaj bi se zgodilo, če ne bi storili absolutno ničesar:
+Not good.
- -That's what the March 16 Imperial College report found: do nothing, and we run out of ICUs, with more than 80% of the population getting infected. - (remember: total cases overshoots herd immunity)
- -Even if only 0.5% of infected die – a generous assumption when there'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... IF we did nothing.
- -(Lots of news & social media reported "80% will be infected" without "IF WE DO NOTHING". Fear was channelled into clicks, not understanding. Sigh.)
- -Scenario 1: Flatten The Curve / Herd Immunity
- -The "Flatten The Curve" plan was touted by every public health organization, while the United Kingdom's original "herd immunity" plan was universally booed. They were the same plan. The UK just communicated theirs poorly.15
- -Both plans, though, had a literally fatal flaw.
- -First, let's look at the two main ways to "flatten the curve": handwashing & physical distancing.
- -Increased handwashing cuts flus & colds in high-income countries by ~25%16, while the city-wide lockdown in London cut close contacts by ~70%17. So, let's assume handwashing can reduce R by up to 25%, and distancing can reduce R by up to 70%:
- -Play with this calculator to see how % of non-
Slabo kaže…
+Britanska fakulteta je 16. marca (the March 16 Imperial College report) prišla do sledeče ugotovitve: Če ne naredimo ničesar, se bo okužilo več kot 80% prebivalstva in se bomo posledično spopadali s problemom premajhnega števila ležišč na oddelkih intenzivne nege. +(ne pozabite: skupni primeri prekoračijo imunost črede).
+Tudi če umre le 0,5% okuženih – velikodušna domneva, ko ni več možnosti oskrbe na oddelku za intenzivno nego – v veliki državi, kot je ZDA, s 300 milijoni ljudi, 0,5% od 80% od 300 milijonov = še vedno 1,2 milijona mrtvih… ČE nismo naredili ničesar.
+(Številne novice in mediji so poročali, da “bo 80% okuženih”, brez da bi temu priključili še “ČE NISMO NAREDILI NIČESAR”. Strah je bil usmerjen v klike (branje novic), ne pa v razumevanje. Vzdih.)
+Scenarij 1: Izravnajte krivuljo / Čredna imunost
+Načrt “Izravnati krivuljo” je bil predstavljen s strani prav vsake izmed javnih zdravstvenih organizacij, medtem ko je bil prvotni načrt Združenega kraljestva, imenovan “čredna imunost”, splošno razglašen. Šlo je za enak načrt. Razlika je le v tem, da je Združeno kraljestvo svoj načrt sporočilo slabo in površno.[15]
+Oba načrta pa sta imela dobesedno usodno napako.
+Najprej si oglejmo dva glavna načina za “zravnanje krivulje”: pranje rok in fizično distanciranje.
+Povečano pranje rok je v državah z visokim dohodkom zmanjšalo zaščito pred prehladom in mrazom za ~25%[16], medtem ko je mestno zaprtje v Londonu tesne stike zmanjšalo za ~70%[17]. Predpostavimo lahko, da lahko pranje rok R zmanjša za do 25%, distanciranje pa do 70%:
+Preizkusite spodnji kalkulator in videli boste, kako delež ne-
Now, let's simulate what happens to a COVID-19 epidemic if, starting March 2020, we had increased handwashing but only mild physical distancing – so that R is lower, but still above 1:
- -Sedaj simulirajmo, kaj bi se zgodilo z epidemijo COVID-19, če bi od marca 2020 dalje imeli le povečano pranje rok, fizično distanciranje pa bi ostalo v (pre)blagi obliki – R je tako nižji, vendar še vedno nad 1:
+Three notes:
- --
-
This reduces total cases! Even if you don't get R < 1, reducing R still saves lives, by reducing the 'overshoot' above herd immunity. Lots of folks think "Flatten The Curve" spreads out cases without reducing the total. This is impossible in any Epidemiology 101 model. But because the news reported "80%+ will be infected" as inevitable, folks thought total cases will be the same no matter what. Sigh.
- Due to the extra interventions, current cases peak before herd immunity is reached. In fact, in this simulation, total cases only overshoots a tiny bit above herd immunity – the UK's plan! At that point, R < 1, you can let go of all other interventions, and COVID-19 stays contained! Well, except for one problem...
- You still run out of ICUs. For several months. (and remember, we already tripled ICUs for these simulations)
-
That was the other finding of the March 16 Imperial College report, which convinced the UK to abandon its original plan. Any attempt at mitigation (reduce R, but R > 1) will fail. The only way out is suppression (reduce R so that R < 1).
- -
That is, don't merely "flatten" the curve, crush the curve. For example, with a...
- -Scenario 2: Months-Long Lockdown
- -Let's see what happens if we crush the curve with a 5-month lockdown, reduce
Tri opombe:
+-
+
-
+
To zmanjšuje skupno število primerov! Četudi ne dobite R < 1, nižanje R na način, da poskušamo zmanjševati ‘prekoračitve’ nad imunostjo črede, še vedno rešuje življenja. Večina ljudi misli, da načrt “Izravnati krivuljo” le širi primere, ne da bi pri tem zmanjšali celoto. Vendar to ni mogoče v nobenem epidemiološkem modelu. Ker pa so mediji kot neizogibno dejstvo poročali, da bo “okuženih več kot 80% ljudi”, so ljudje posledično mislili, da bodo skupni primeri enaki ne glede na vse. Vzdih.
+
+ -
+
Zaradi dodatnih ukrepov trenutni primeri dosežejo vrhunec preden se doseže čredna imunost. Dejansko v tej simulaciji skupni primeri prispevajo le majhen delček k čredni imunosti – gre za načrt Združenega kraljestva! Na tej točki, kjer je R < 1, lahko opustimo vse druge ukrepe in virus nam je uspelo uspešno zajeziti! Srečamo se le z eno težavo…
+
+ -
+
Še vedno nam primanjkuje enot za intenzivno nego. In to za kar nekaj mesecev (in ne pozabite, za te simulacije smo število enot za intenzivno nego že potrojili).
+
+
To je bila druga ugotovitev v študiji Imperial College (objavljeni 16. marec), ki je oblasti Združenega kraljestva uspela prepričati, da opusti svoj prvotni načrt. Vsak poskus blaženja (zmanjšati R, vendar ostane R > 1) bo spodletel. Edini izhod je zaviranje virusa (zmanjšati R tako, da je R < 1).
+
Se pravi, krivulje ne le “izravnajte”, potrebno jo je zdrobiti. Na primer z …
+Scenarij 2: Nekajmesečno zaprtje
+Poglejmo, kaj se zgodi, če krivuljo zatremo s 5-mesečnim zaprtjem,
Ojej.
+Gre za “drugi val” o katerem že vsi govorijo. Takoj, ko odstranimo zaprtje, ponovno dobimo R > 1. Torej lahko en sam izpuščen
Zaprtje ni zdravilo, je le vrnitev na začetek.
+Torej se znova in znova le zapiramo?
+Scenarij 3: Občasno zaprtje
+Ta rešitev je bila sprva predlagana v študiji Imperial College z dne 16. marca, kasneje pa še v raziskavi Univerze Harvard.[19]
-Oh.
- -This is the "second wave" everyone's talking about. As soon as we remove the lockdown, we get R > 1 again. So, a single leftover
A lockdown isn't a cure, it's just a restart.
- -So, what, do we just lockdown again & again?
- -Scenario 3: Intermittent Lockdown
- -This solution was first suggested by the March 16 Imperial College report, and later again by a Harvard paper.19
- -Here's a simulation: (After playing the "recorded scenario", you can try simulating your own lockdown schedule, by changing the sliders while the simulation is running! Remember you can pause & continue the sim, and change the simulation speed)
- -Tukaj je simulacija: (Po predvajanju “posnetega scenarija” lahko poskusite simulirati svoj urnik zaprtja tako, da spremenite drsnike, medtem ko simulacija teče! Ne pozabite, da lahko zaustavite in nadaljujete simulacijo ter spremenite njeno hitrost.)
+This would keep cases below ICU capacity! And it's much 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's no vaccine, repeat until herd immunity is reached... in 2022.)
- -Look, it's nice to draw a line saying "ICU capacity", but there's lots of important things we can't simulate here. Like:
- -Mental Health: Loneliness is one of the biggest risk factors for depression, anxiety, and suicide. And it's as associated with an early death as smoking 15 cigarettes a day.20
- -Financial Health: "What about the economy" sounds like you care more about dollars than lives, but "the economy" isn't just stocks: it's people's ability to provide food & shelter for their loved ones, to invest in their kids' futures, and enjoy arts, foods, videogames – the stuff that makes life worth living. And besides, poverty itself has horrible impacts on mental and physical health.
- -Not saying we shouldn't lock down again! We'll look at "circuit breaker" lockdowns later. Still, it's not ideal.
- -But wait... haven't Taiwan and South Korea already contained COVID-19? For 4 whole months, without long-term lockdowns?
- -How?
- -Scenario 4: Test, Trace, Isolate
- -"Sure, we *could've* done what Taiwan & South Korea did at the start, but it's too late now. We missed the start."
- -But that's exactly it! “A lockdown isn't a cure, it's just a restart”... and a fresh start is what we need.
- -To understand how Taiwan & South Korea contained COVID-19, we need to understand the exact timeline of a typical COVID-19 infection21:
- -
If cases only self-isolate when they know they're sick (that is, they feel symptoms), the virus can still spread:
- -
And in fact, 44% of all transmissions are like this: pre-symptomatic! 22
- -But, if we find and quarantine a symptomatic case's recent close contacts... we stop the spread, by staying one step ahead!
- -
This is called contact tracing. It's an old idea, was used at an unprecedented scale to contain Ebola23, and now it's core part of how Taiwan & South Korea are containing COVID-19!
- -(It also lets us use our limited tests more efficiently, to find pre-symptomatic
Traditionally, contacts are found with in-person interviews, but those alone are too slow for COVID-19's ~48 hour window. That's why contact tracers need help, and be supported by – NOT replaced by – contact tracing apps.
- -(This idea didn't come from "techies": using an app to fight COVID-19 was first proposed by a team of Oxford epidemiologists.)
- -Wait, apps that trace who you've been in contact with?... Does that mean giving up privacy, giving in to Big Brother?
- -Heck no! DP-3T, a team of epidemiologists & cryptographers (including one of us, Marcel Salathé) is already making a contact tracing app – with code available to the public – that reveals no info about your identity, location, who your contacts are, or even how many contacts you've had.
- -Here's how it works:
- -
Along with similar teams like TCN Protocol24 and MIT PACT25, they've inspired Apple & Google to bake privacy-first contact tracing directly into Android/iOS.26 (Don't trust Google/Apple? Good! The beauty of this system is it doesn't need trust!) Soon, your local public health agency may ask you to download an app. If it's privacy-first with publicly-available code, please do!
- -But what about folks without smartphones? Or infections through doorknobs? Or "true" asymptomatic cases? Contact tracing apps can't catch all transmissions... and that's okay! We don't need to catch all transmissions, just 60%+ to get R < 1.
- -(Rant about the confusion about pre-symptomatic vs "true" asymptomatic. "True" asymptomatics are rare:27)
- -Isolating symptomatic cases would reduce R by up to 40%, and quarantining their pre/a-symptomatic contacts would reduce R by up to 50%28:
- -To bi primere ohranilo znotraj kapacitete enot za intenzivno nego, kar je veliko bolje, kot 18-mesečna popolna zaustavitev, dokler cepivo ne bi bilo na voljo. Za nekaj mesecev moramo uvesti zaprtje, nato ponovno odpreti za nekaj mesecev in to potem ponavljati, dokler cepivo ne bo na voljo. (In če cepiva še kar ni, to ponavljajte, dokler čredna imunost ni dosežena … torej do leta 2022.)
+Poglejte, naravnost čudovito je narisati črto, ki predstavlja “kapaciteto enot za intenzivno nego”, vendar se srečamo še z veliko ostalimi pomembnimi stvarmi, ki pa jih tukaj ne moremo simulirati. Mednje štejemo:
+Duševno zdravje: Osamljenost je eden največjih dejavnikov tveganja za depresijo, tesnobo in samomor. To bi lahko primerjali s kajenjem 15 cigaret na dan, kar prav tako privede do zgodnje smrti.[20]
+Finančno zdravje: “Kaj pa gospodarstvo?” zveni, kot da vas bolj kot za življenja skrbi za denar. Vendar “ekonomija” ni le materialno stanje: gre za sposobnost ljudi, da lahko svojim najdražjim zagotovijo hrano in streho nad glavo, da imajo možnost vlagati v prihodnost svojih otrok in preprosto uživajo v umetnosti, hrani, videoigrah – v glavnem v tistem, zaradi česar je življenje vredno živeti. Poleg tega je vredno omeniti, da revščina sama po sebi strahotno vpliva na duševno in fizično zdravje.
+Ne pravimo, da smo proti ponovnemu zaprtju! Kasneje si bomo ogledali zaprtje, ki ga bomo poimenovali “varnostno stikalo”. Kljub vsemu, ne gre za idealen način zaprtja.
+Vendar pozor… Ali se nista Tajvan in Južna Koreja že pred časom srečala s COVID-19? 4 cele mesece brez dolgotrajnega zaprtja?
+Kako?
+Scenarij 4: Testiraj, izsled, izoliraj
+"Seveda, tudi mi *bi lahko* naredili tisto, kar sta Tajvan in Južna Koreja storila že na začetku, vendar je sedaj že prepozno. Zamudili smo začetek."
+Ampak gre ravno za to! “Zaustavitev ni zdravilo, je le ponovni zagon”… in vse, kar potrebujemo, je nov začetek.
+Da bi razumeli, kako sta se Tajvan in Južna Koreja znali spopadati s COVID-19, moramo razumeti natančen časovni trak tipične okužbe s COVID-19[21]:
+
Če se primeri samoizolirajo, ko že vedo, da so bolni (torej, ko čutijo simptome), se virus lahko še vedno širi:
+
In v resnici je 44% vseh prenosov prav takšnih: predsimptomatskih! [22]
+Vendar, če najdemo in damo v karanteno ljudi, ki so bili še nedavno v tesnejših stikih in imajo simptome virusa, lahko tako širjenje virusa ustavimo in ostanemo korak spredaj!
+
Temu pravimo sledenje stikov. Gre za starejšo idejo, ki je bila v neprimerljivem obsegu uporabljena za obvladovanje ebole[23], sedaj pa se pri zajezitvi COVID-19 po njej zgledujeta predvsem Tajvan in Južna Koreja!
+(Omogoča nam tudi učinkovitejšo uporabo naših omejenih testov za iskanje predsimptomatskih
Navadno je stike moč najti z osebnimi pogovori, vendar so v našem primeru le ti sami prepočasni za t.i. 48-urno okno COVID-19. Zaradi tega sledilci stikov še kako potrebujejo pomoč, pri čemer pridejo v poštev (in NE v nadomestilo) aplikacije za sledenje stikov.
+(Ta ideja ni prišla s strani računalničarjev: uporaba aplikacije za boj proti COVID-19 je bila sprva predlagana s strani ekipe Oxford-skih epidemiologov.)
+Čakaj, aplikacije, ki beležijo s kom si bil v stiku? … Ali to pomeni, da se odrekamo zasebnosti in jo dajemo “Velikemu bratu”?
+Seveda ne! DP-3T, +skupina epidemiologov & kriptografov (eden izmed njih je Marcel Salathé) že dela na tej aplikaciji – +odprtokodno – ki ne razkrije nobenih informacij o tvoji identiteti, lokaciji, s kom +ali celo s koliko ljudmi si bil v stiku.
+Tako deluje:
+
(& Tukaj je celoten strip (v angleščini).)
+Skupaj s podobnimi skupinami kot so TCN Protocol[24] in MIT PACT[25], so navdihnili podjetji Apple & Google +za razvoj sledenja stikov, katerega prioriteta je varovanje zasebnosti neposredno za sistema Android/iOS.[26] +(Ne zaupaš Google-u/Apple-u? Dobro! Lepota sistema je, da ne potrebuje zaupanja.) +Kmalu bo lokalna zdravstena agencija morda predlagala, da jo preneseš. Če je prioriteta aplikacije varovanje zasebnosti z javno dostopno kodo, +jo, prosim, prenesi!
+Kaj pa ljudje brez pametnih telefonov? Ali pa okužbe preko “vratnih kljuk”? Ali “popolnoma” asimptomatski primeri? Aplikacije sledenja stikov ne morejo prestreči vseh prenosov … Kar je čisto v redu! Ni nam treba prestreči vseh, vsaj 60%, da je R < 1.
+(Obstajajo nesporazumi glede zmede med pre-simptomatskimi in popolnoma asimptomatskimi. Slednji so redki [27].)
+Izolacija simptomatskih primerov bi znižala R do 40 % in karantenizacija njihovih pre/a-simptomatskih stikov bi znižala R vse do 50 %[28]:
+Thus, even without 100% contact quarantining, we can get R < 1 without a lockdown! Much better for our mental & financial health. (As for the cost to folks who have to self-isolate/quarantine, governments should support them – pay for the tests, job protection, subsidized paid leave, etc. Still way cheaper than intermittent lockdown.)
- -We then keep R < 1 until we have a vaccine, which turns susceptible
Četudi se 100% stikov ne osami, lahko dobimo R < 1 brez karantene! Veliko boljše za naše mentalno in finančno zdravje. +(Kar se tiče stroškov ljudi, ki se morajo samoosamiti in so v karanteni, bi jih vlada morala podpreti – plačati teste, preprečiti izgubo službe, subvencionirati plačani dopust, itd. Še vedno veliko ceneje od popolne karantene za vse.)
+Potem ohranjamo R < 1, dokler nimamo zdravila, ki spremeni dovzetne
(Note: this calculator pretends the vaccines are 100% effective. Just remember that in reality, you'd have to compensate by vaccinating more than "herd immunity", to actually get herd immunity)
- -Okay, enough talk. Here's a simulation of:
- --
-
- A few-month lockdown, until we can... -
- Switch to "Test, Trace, Isolate" until we can... -
- Vaccinate enough people, which means... -
- We win. -
(Pomni: ta kalkulator privzema, da je zdravilo 100% učinkovito. Ne pozabi, da bomo morali v realnosti kompenzirati cepljenje več kot “čredne imunosti”, da dejansko dobimo čredno imunost).
+Dobro, dovolj govorjenja. Tukaj je simulacija za:
+-
+
- Nekaj mesečno karanteno, dokler ne … +
- Preklopimo na “Testiraj, Izsledi, Izoliraj” dokler ne… +
- Cepimo dovolj ljudi, kar pomeni… +
- Zmagali smo. +
So that's it! That's how we make an emergency landing on this plane.
- -That's how we beat COVID-19.
- -...
- -But what if things still go wrong? Things have gone horribly wrong already. That's fear, and that's good! Fear gives us energy to create backup plans.
- -The pessimist invents the parachute.
- -Scenario 4+: Masks For All, Summer, Circuit Breakers
- -What if R0 is way higher than we thought, and the above interventions, even with mild distancing, still aren't enough to get R < 1?
- -Remember, even if we can't get R < 1, reducing R still reduces the "overshoot" in total cases, thus saving lives. But still, R < 1 is the ideal, so here's a few other ways to reduce R:
- -Masks For All:
- -"Wait," you might ask, "I thought face masks don't stop you from getting sick?"
- -You're right. Masks don't stop you from getting sick29... they stop you from getting others sick.
- -
To put a number on it: surgical masks on the sick person reduce cold & flu viruses in aerosols by 70%.30 Reducing transmissions by 70% would be as large an impact as a lockdown!
- -However, we don't know for sure the impact of masks on COVID-19 specifically. In science, one should only publish a finding if you're 95% sure of it. (...should.31) Masks, as of May 1st 2020, are less than "95% sure".
- -However, pandemics are like poker. Make bets only when you're 95% sure, and you'll lose everything at stake. As a recent article on masks in the British Medical Journal notes,32 we have to make cost/benefit analyses under uncertainty. Like so:
- -Cost: If homemade cloth masks (which are ~2/3 as effective as surgical masks33), super cheap. If surgical masks, more expensive but still pretty cheap.
- -Benefit: Even if it's a 50–50 chance of surgical masks reducing transmission by 0% or 70%, the average "expected value" is still 35%, same as a half-lockdown! So let's guess-timate that surgical masks reduce R by up to 35%, discounted for our uncertainty. (Again, you can challenge our assumptions by turning the sliders up/down)
- -Torej, to je to! Tako izvedemo zasilni pristanek na tem letu.
+Tako premagamo COVID-19.
+…
+Kaj pa, če gredo stvari še vedno narobe? +Stvari so že ušle izpod nadzora. To vzbuja strah in to je dobro! Strah nam da energijo, da ustvarimo rezervne načrte.
+Pesimist izumi padalo.
+Scenarij 4+: Maske za vse poletje, varnostno stikalo
+Kaj če je R0 veliko višji kot smo predvideli in zgornji posegi, tudi z blagim distanciranjem, še vedno niso dovolj, da dosežemo R < 1?
+Ne pozabi,
+tudi če ne moremo doseči R < 1, zmanjšanje R še vedno zniža “presežek” v skupnih primerih, kar reši življenja.
+Kljub temu je R < 1 idealen, zato je tu še nekaj načinov za zmanjšanje R:
Maske za vse:
+“Počakaj,” morda se boš vprašal, “mislil sem, da maska za obraz ne prepreči, da bi zbolel?”
+Prav imaš. Maska ne prepreči, da bi zbolel[29]… prepreči pa ti, da bi okužil ostale.
+
Predstavljeno v številkah: kirurška maska na zboleli osebi zmanjša prenos virusa pri prehladu & gripi preko zraka do 70 %.[30] Zmanjšanje prenosov za 70 % bi imelo tako velik vpliv kot karantena!
+Vseeno, ne vemo zagotovo kakšen vpliv imajo maske pri virusu COVID-19 specifično. V znanosti se ugotovitev lahko objavi samo, če je gotovost 95 %. (…lahko.[31]) Maske imajo, od 1. maja 2020, "manjšo zanesljivost od 95 %".
+Pandemija je kot poker. Če staviš zgolj, ko si 95% prepričan, boš izgubil vse. Kot ugotavlja nedavni članek o maskah v Britanski medicinski reviji,[32] moramo analizo stroškov in koristi narediti z upoštevanjem negotovosti. Kot so:
+Cena: V primeru doma izdelanih mask iz blaga (imajo približno 2/3 učinkovitosti kirurških mask [33]) je cena zelo ugodna. V primeru kirurških mask je cena višja, a še vedno precej ugodna.
+Korist: Tudi če je 50% možnosti, da kirurške maske znižajo prenos za 0 % ali 70 %, je povprečna “pričakovana vrednost” še zmeraj 35 %. Tako kot polovično zaprtje! Torej ugibajmo, da zaradi negotovosti kirurške maske znižajo R za največ 35%. (Ponovno, lahko preveriš naše predpostavke s premikanjem drsnikov gor ali dol.)
+(other arguments for/against masks:34)
- -Masks alone won't get R < 1. But if handwashing & "Test, Trace, Isolate" only gets us to R = 1.10, having just 1/3 of people wear masks would tip that over to R < 1, virus contained!
- -Summer:
- -Okay, this isn't an "intervention" we can control, but it will help! Some news outlets report that summer won't do anything to COVID-19. They're half right: summer won't get R < 1, but it will reduce R.
- -For COVID-19, every extra 1° Celsius (2.2° Fahrenheit) makes R drop by 1.2%.35 The summer-winter difference in New York City is 15°C (60°F), so summer will make R drop by 18%.
- -(Ostali argumenti za/proti maskam:[34])
+Maske same ne bodo privedle do R < 1. Toda če nas umivanje rok in “Testiraj, Izsledi, Izoliraj” privede zgolj do R = 1,10, bi z nošo mask 1/3 ljudi dosegli R < 1 in virus obvladali!
+Poletje:
+Ok, to ni “intervencija”, ki jo lahko nadzorujemo, lahko pa pomaga! Nekatere novice poročajo, da poletje ne bo vplivalo na širjenje COVID-19. Imajo deloma prav: poletje ne bo zagotovilo R < 1, vendar ga bo zmanjšalo.
+Pri COVID-19 vsaka dodatna 1 °C (2,2 ° Fahrenheit) povzroči upad R za 1,2 %.[35]
+Temperaturna razlika poletje-zima je v New Yorku 15 °C (60 °F), torej bo s poletjem upad R za 18 %.
Summer alone won't make R < 1, but if we have limited resources, we can scale back some interventions in the summer – so we can scale them higher in the winter.
- -A "Circuit Breaker" Lockdown:
- -And if all that still isn't enough to get R < 1... we can do another lockdown.
- -But we wouldn't have to be 2-months-closed / 1-month-open over & over! Because R is reduced, we'd only need one or two more "circuit breaker" lockdowns before a vaccine is available. (Singapore had to do this recently, "despite" having controlled COVID-19 for 4 months. That's not failure: this is what success takes.)
- -Here's a simulation a "lazy case" scenario:
- --
-
- Lockdown, then -
- A moderate amount of hygiene & "Test, Trace, Isolate", with a mild amount of "Masks For All", then... -
- One more "circuit breaker" lockdown before a vaccine's found. -
Poletje samo ne bo doseglo R < 1, če pa imamo omejene vire, lahko zmanjšamo ukrepe poleti – da jih lahko zaostrimo pozimi.
+"Varnostno stikalo" - zaprtje:
+In če vse to še vedno ni dovolj, da dobimo R < 1… lahko ponovno uvedemo karanteno.
+Ampak ne bo nam treba biti 2-mesca-zaprti(ukazana karantena) / 1-mesec-odprti znova in znova! Ker je R zmanjšan, bomo potrebovali zgolj še eno ali dve "varnostni stikali"-zaprtji, preden bo na voljo cepivo. (Singapur je moral to narediti pred kratkim, “kljub” temu da je COVID-19 bil pod kontrolo 4 mesece. To ni neuspeh: to je “cena, ki jo moraš plačati”, da zmagaš.)
+Tu je simulacija “lenega primera” scenarija:
+-
+
- Karantena, +
- Zmerna količina higiene & "Testiraj, Izsledi, Izoliraj" z blago zalogo "Maske za vse" … +
- Samo še eno “varnostno stikalo” - ukazana popolna karantena pred iznajdbo cepiva. +
Not to mention all the other interventions we could do, to further push R down:
- --
-
- Travel restrictions/quarantines -
- Temperature checks at malls & schools -
- Deep-cleaning public spaces -
- Replacing hand-shaking with foot-bumping -
- And all else human ingenuity shall bring -
. . .
- -We hope these plans give you hope.
- -Even under a pessimistic scenario, it is possible to beat COVID-19, while protecting our mental and financial health. Use the lockdown as a "reset button", keep R < 1 with case isolation + privacy-protecting contract tracing + at least cloth masks for all... and life can get back to a normal-ish!
- -Sure, you may have dried-out hands. But you'll get to invite a date out to a comics bookstore! You'll get to go out with friends to watch the latest Hollywood cash-grab. You'll get to people-watch at a library, taking joy in people going about the simple business of being alive.
- -Even under the worst-case scenario... life perseveres.
- -So now, let's plan for some worse worst-case scenarios. Water landing, get your life jacket, and please follow the lights to the emergency exits:
+Da ne omenjam vseh ostalih ukrepov, ki še dodatno znižajo R:
+-
+
- omejitve potovanj / karantene potnikov, +
- preverjanje temperature v trgovskih centrih & šolah, +
- temeljito čiščenje javnih površin, +
- nadomestimo rokovanje z brco nog, +
- in vse ostalo kar prinese človeška iznajdljivost. +
. . .
+Upamo, da smo ti s temi načrti vlili upanje.
+Tudi po pesimističnem scenariju je mogoče premagati COVID-19 in hkrati zaščititi naše mentalno in finančno zdravje. Glej na ukazano popolno karanteno kot na “gumb za ponovni zagon”, vzdržujmo R < 1 z izolacijo okuženih + sledenje stikov na način, ki zaščiti zasebnost + vsaj maske iz blaga za vse… in življenje lahko ponovno postane normalno!
+Seveda, morda imaš izsušene roke, ampak boš lahko zaradi tega povabil partnerja v knjigarno stripov! Lahko boš šel ven s prijatelji gledat najnovejšo hollywoodsko uspešnico. Zalotili se boste, da opazujete ljudi v knjižnici in veselje ljudi, ki živijo preprosto življenje.
+Celo v najhujšem primeru … Se življenje ohrani.
+Zatorej se zdaj pripravimo na najhujše možne primere. Pristanek na vodi, vzemi svoj rešilni jopič in sledi lučkam do zasilnih izhodov:
- You get COVID-19, and recover. Or you get the COVID-19 vaccine. Either way, you're now immune...
- -...for how long?
- --
-
- COVID-19 is most closely related to SARS, which gave its survivors 2 years of immunity.36 -
- The coronaviruses that cause "the" common cold give you 8 months of immunity.37 -
- There's reports of folks recovering from COVID-19, then testing positive again, but it's unclear if these are false positives.38 -
- One not-yet-peer-reviewed study on monkeys showed immunity to the COVID-19 coronavirus for at least 28 days.39 -
But for COVID-19 in humans, as of May 1st 2020, "how long" is the big unknown.
- -For these simulations, let's say it's 1 year.
- Here's a simulation starting with 100%
Stakneš virus COVID-19 in si opomoreš, ali pa se proti njemu cepiš. V vsakem primeru si zdaj imun …
+…A kako dolgo?
+-
+
- Virus COVID-19 je najbolj podoben virusu SARS, ki je dal “svojim” preživelim 2 leti imunosti.[36] +
- Corona virusi, ki so vzrok za navaden prehlad, vzbudijo le 8 mesecev imunosti.[37] +
- Obstajajo poročila ljudi, ki so preboleli COVID-19, potem pa bili pozitivni. Je pa neznano, če so testi lažno pozitivni.[38] +
- Ena “nestrokovno pregledana” raziskava na opicah je pokazala imunost na COVID-19 za vsaj 28 let.[39] +
Pri ljudeh je od 1. maja 2020 trajanje imunosti en velik vprašaj.
+Za te simulacije recimo, da je 1 leto.
+Tu je simulacija, začenši s 100%
Return of the exponential decay!
- -This is the SEIRS Model. The final "S" stands for
Now, let's simulate a COVID-19 outbreak, over 10 years, with no interventions... if immunity only lasts a year:
- -Vrnimo se na eksponentni upad!
+To je SEIRS Model. Zadnji “S” pomeni
Zdaj pa simulirajmo izbruh virusa COVID-19 v obdobju več kot 10 let brez ukrepov … Če imunost traja le leto dni:
+In previous simulations, we only had one ICU-overwhelming spike. Now, we have several, and
R = 1, it's endemic.
- -Thankfully, because summer reduces R, it'll make the situation better:
- -V prejšnjih simulacijah smo imeli le en sunek preobremenitve na intenzivni negi. Zdaj pa jih imamo več in
R = 1, endemično.
+K sreči poletje oziroma višje temperature zmanjšujejo R, zato se bo stanje izboljšalo:
+Oh.
- -Counterintuitively, summer makes the spikes worse and regular! This is because summer reduces new
Thankfully, the solution to this is pretty straightforward – just vaccinate people every fall/winter, like we do with flu shots:
- -(After playing the recording, try simulating your own vaccination campaigns! Remember you can pause/continue the sim at any time)
- -Oh.
+Intuitivno, poletje povzroči, da so sunki okužbe hujši in regularni! To je zato, ker poletje zmanjšuje nove
Na srečo je rešitev za to preprosta - ljudi je potrebno vsako jesen/zimo cepiti, tako kot pri gripi:
+(Po predvajanju posnetka poskusite simulirati lastne akcije cepljenja! Ne pozabite, da lahko simulacijo začasno zaustavite/nadaljujete.)
+But here's the scarier question:
- -What if there's no vaccine for years? Or ever?
- -To be clear: this is unlikely. Most epidemiologists expect a vaccine in 1 to 2 years. Sure, there's never been a vaccine for any of the other coronaviruses before, but that's because SARS was eradicated quickly, and "the" common cold wasn't worth the investment.
- -Still, infectious disease researchers have expressed worries: What if we can't make enough?40 What if we rush it, and it's not safe?41
- -Even in the nightmare "no-vaccine" scenario, we still have 3 ways out. From most to least terrible:
- -1) Do intermittent or loose R < 1 interventions, to reach "natural herd immunity". (Warning: this will result in many deaths & damaged lungs. And won't work if immunity doesn't last.)
- -2) Do the R < 1 interventions forever. Contact tracing & wearing masks just becomes a new norm in the post-COVID-19 world, like how STI tests & wearing condoms became a new norm in the post-HIV world.
- -3) Do the R < 1 interventions until we develop treatments that make COVID-19 way, way less likely to need critical care. (Which we should be doing anyway!) Reducing ICU use by 10x is the same as increasing our ICU capacity by 10x:
- -Here's a simulation of no lasting immunity, no vaccine, and not even any interventions – just slowly increasing capacity to survive the long-term spikes:
- -Toda tukaj se pojavi bolj strašno vprašanje:
+Kaj pa če cepiva ne bo več let? Ali nikoli?
+Da bo jasno: to je malo verjetno. Večina epidemiologov pričakuje cepivo čez 1 do 2 leti. Seveda še nikoli ni bilo cepiva za katerega koli od drugih koronavirusov, toda to je zato, ker je bil SARS hitro izkoreninjen in “navadni prehlad” ni bil vreden naložbe.
+Kljub temu so raziskovalci nalezljivih bolezni izrazili zaskrbljenost: Kaj, če ga ne bomo mogli narediti dovolj?[38] Kaj, če preveč pohitimo in cepivo ne bo varno?[39]
+Tudi v najslabšem scenariju “brez cepiva” imamo še vedno 3 poti. Od najbolj do najmanj groznega scenarija:
+-
+
-
+
Izvedemo občasne ali ohlapne R < 1 ukrepe, da dosežemo naravno imunost ljudi. (Opozorilo: To bo povzročilo veliko smrtnih žrtev in poškodovanih pljuč pri ljudeh. In ne bo delovalo, če imunost ne bo trajala.)
+
+ -
+
Sprejmimo R < 1 ukrepe za vedno. Sledenje stikov in nošenje mask postane nova norma v svetu po COVID-19, denimo kot so testi STI in uporaba kondomov postali nova norma v svetu po HIV.
+
+ -
+
Sprejmimo R < 1 ukrepe, dokler ne razvijejo zdravljenja za COVID-19, po katem je manj verjetno, da bi ljudje potrebovali intenzivno nego. (Kar bi morali storiti kljub vsemu!) Zmanjšanje uporabe EIN za 10x je isto kot povečanje naše zmogljivosti EIN za 10x:
+
+
Tu je simulacija brez trajne imunosti brez cepiva in nikakršnega posega:
+Even under the worst worst-case scenario... life perseveres.
- -. . .
- -Maybe you'd like to challenge our assumptions, and try different R0's or numbers. Or try simulating your own combination of intervention plans!
- -Here's an (optional) Sandbox Mode, with everything available. (scroll to see all controls) Simulate & play around to your heart's content:
- -Tudi v najslabšem najslabšem primeru … življenje vztraja.
+. . .
+Morda dvomite v naše predpostavke in bi jih želeli izpodbiti. Preizkusite lahko različne R0 ali številke ter celo poskusite simulirati svojo kombinacijo intervencijskih načrtov!
+Pred vami je (izbiren) t. i. način peskovnika, ki ima na voljo prav vse. (Pomaknite se nižje in si oglejte vse krmilne tipke.) Simulirajte in igrajte se kolikor dolgo želite:
+This basic "epidemic flight simulator" has taught us so much. It's let us answer questions about the past few months, next few months, and next few years.
- -So finally, let's return to...
+Še tako osnovna “simulacija letenja z epidemijo” nas je naučila ogromno. Dovolite nam odgovoriti na vprašanja glede zadnjih nekaj mesecev, naslednjih nekaj mesecev in naslednjih nekaj let.
+Torej, končno se vrnimo k …
- Plane's sunk. We've scrambled onto the life rafts. It's time to find dry land.42
- -Teams of epidemiologists and policymakers (left, right, and multi-partisan) have come to a consensus on how to beat COVID-19, while protecting our lives and liberties.
- -Here's the rough idea, with some (less-consensus) backup plans:
- -
So what does this mean for YOU, right now?
- -For everyone: Respect the lockdown so we can get out of Phase I asap. Keep washing those hands. Make your own masks. Download a privacy-protecting contact tracing app when those are available next month. Stay healthy, physically & mentally! And write your local policymaker to get off their butt and...
- -For policymakers: Make laws to support folks who have to self-isolate/quarantine. Hire more manual contact tracers, supported by privacy-protecting contact tracing apps. Direct more funds into the stuff we should be building, like...
- -For builders: Build tests. Build ventilators. Build personal protective equipment for hospitals. Build tests. Build masks. Build apps. Build antivirals, prophylactics, and other treatments that aren't vaccines. Build vaccines. Build tests. Build tests. Build tests. Build hope.
- -Don't downplay fear to build up hope. Our fear should team up with our hope, like the inventors of airplanes & parachutes. Preparing for horrible futures is how we create a hopeful future.
- -The only thing to fear is the idea that the only thing to fear is fear itself.
- --
-
-
-
-
-
These footnotes will have sources, links, or bonus commentary. Like this commentary! ↩
- -This guide was published on May 1st, 2020. Many details will become outdated, but we're confident this guide will cover 95% of possible futures, and that Epidemiology 101 will remain forever useful.
-
-
- -
-
“The mean [serial] interval was 3.96 days (95% CI 3.53–4.39 days)”. Du Z, Xu X, Wu Y, Wang L, Cowling BJ, Ancel Meyers L (Disclaimer: Early release articles are not considered as final versions) ↩
-
-
- -
-
Remember: all these simulations are super simplified, for educational purposes. ↩
- -One simplification: When you tell this simulation "Infect 1 new person every X days", it's actually increasing # of infected by 1/X each day. Same for future settings in these simulations – "Recover every X days" is actually reducing # of infected by 1/X each day.
- -Those aren't exactly the same, but it's close enough, and for educational purposes it's less opaque than setting the transmission/recovery rates directly.
-
-
- -
-
“The median communicable period [...] was 9.5 days.” Hu, Z., Song, C., Xu, C. et al Yes, we know "median" is not the same as "average". For simplified educational purposes, close enough. ↩
-
-
- -
-
For more technical explanations of the SIR Model, see the Institute for Disease Modeling and Wikipedia ↩
-
-
- -
-
For more technical explanations of the SEIR Model, see the Institute for Disease Modeling and Wikipedia ↩
-
-
- -
-
“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, 0.8–3.0 days) before symptom onset” (translation: Assuming symptoms start at 5 days, infectiousness starts 2 days before = Infectiousness starts at 3 days) He, X., Lau, E.H.Y., Wu, P. et al. ↩
-
-
- -
-
“The median R value for seasonal influenza was 1.28 (IQR: 1.19–1.37)” Biggerstaff, M., Cauchemez, S., Reed, C. et al. ↩
-
-
- -
-
“We estimated the basic reproduction number R0 of 2019-nCoV to be around 2.2 (90% high density interval: 1.4–3.8)” Riou J, Althaus CL. ↩
-
-
- -
-
“we calculated a median R0 value of 5.7 (95% CI 3.8–8.9)” Sanche S, Lin YT, Xu C, Romero-Severson E, Hengartner N, Ke R. ↩
-
-
- -
-
This is pretending that you're equally infectious all throughout your "infectious period". Again, simplifications for educational purposes. ↩
-
-
- -
-
Remember R = R0 * the ratio of transmissions still allowed. Remember also that ratio of transmissions allowed = 1 - ratio of transmissions stopped. ↩
- -Therefore, to get R < 1, you need to get R0 * TransmissionsAllowed < 1.
- -Therefore, TransmissionsAllowed < 1/R0
- -Therefore, 1 - TransmissionsStopped < 1/R0
- -Therefore, TransmissionsStopped > 1 - 1/R0
- -Therefore, you need to stop more than 1 - 1/R0 of transmissions to get R < 1 and contain the virus!
-
-
- -
-
"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". Between 4.9% to 11.5% of all COVID-19 cases required ICU. Generously picking the lower range, that's 5% or 1 in 20. Note that this total is specific to the US's age structure, and will be higher in countries with older populations, lower in countries with younger populations. ↩
-
-
- -
-
“Number of ICU beds = 96,596”. From the Society of Critical Care Medicine USA Population was 328,200,000 in 2019. 96,596 out of 328,200,000 = roughly 1 in 3400. ↩
-
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-
“He 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; it’s a side effect, not an aim. [...] The government’s actual coronavirus action plan, available online, doesn’t mention herd immunity at all.” ↩
- - -
-
- -
-
“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 6–40%)].” We rounded up the pooled value to 25% in these simulations for simplicity. Rabie, T. and Curtis, V. Note: as this meta-analysis points out, the quality of studies for handwashing (at least in high-income countries) are awful. ↩
-
-
- -
-
“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. Jarvis and Zandvoort et al ↩
-
-
- -
-
This distortion would go away if we plotted R on a logarithmic scale... but then we'd have to explain logarithmic scales. ↩
-
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“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.” Kissler and Tedijanto et al ↩
-
-
- -
-
See Figure 6 from Holt-Lunstad & Smith 2010. Of course, big disclaimer that they found a correlation. But unless you want to try randomly assigning people to be lonely for life, observational evidence is all you're gonna get. ↩
-
-
- -
-
3 days on average to infectiousness: “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, 0.8–3.0 days) before symptom onset” (translation: Assuming symptoms start at 5 days, infectiousness starts 2 days before = Infectiousness starts at 3 days) He, X., Lau, E.H.Y., Wu, P. et al. ↩
- -4 days on average to infecting someone else: “The mean [serial] interval was 3.96 days (95% CI 3.53–4.39 days)” Du Z, Xu X, Wu Y, Wang L, Cowling BJ, Ancel Meyers L
- -5 days on average to feeling symptoms: “The median incubation period was estimated to be 5.1 days (95% CI, 4.5 to 5.8 days)” Lauer SA, Grantz KH, Bi Q, et al
-
-
- -
-
“We estimated that 44% (95% confidence interval, 25–69%) of secondary cases were infected during the index cases’ presymptomatic stage” He, X., Lau, E.H.Y., Wu, P. et al ↩
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- -
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“Contact tracing was a critical intervention in Liberia and represented one of the largest contact tracing efforts during an epidemic in history.” Swanson KC, Altare C, Wesseh CS, et al. ↩
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- -
-
Temporary Contact Numbers, a decentralized, privacy-first contact tracing protocol ↩
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- - - - - -
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Apple and Google partner on COVID-19 contact tracing technology . Note they're not making the apps themselves, just creating the systems that will support those apps. ↩
-
-
- -
-
Lots of news reports – and honestly, many research papers – did not distinguish between "cases who showed no symptoms when we tested them" (pre-symptomatic) and "cases who showed no symptoms ever" (true asymptomatic). The only way you could tell the difference is by following up with cases later. ↩
- -Which is what this study did. (Disclaimer: "Early release articles are not considered as final versions.") In a call center in South Korea that had a COVID-19 outbreak, "only 4 (1.9%) remained asymptomatic within 14 days of quarantine, and none of their household contacts acquired secondary infections."
- -So that means "true asymptomatics" are rare, and catching the disease from a true asymptomatic may be even rarer!
-
-
- -
-
From the same Oxford study that first recommended apps to fight COVID-19: Luca Ferretti & Chris Wymant et al See Figure 2. Assuming R0 = 2.0, they found that: ↩
- --
-
- Symptomatics contribute R = 0.8 (40%) -
- Pre-symptomatics contribute R = 0.9 (45%) -
- Asymptomatics contribute R = 0.1 (5%, though their model has uncertainty and it could be much lower) -
- Environmental stuff like doorknobs contribute R = 0.2 (10%) -
And add up the pre- & a-symptomatic contacts (45% + 5%) and you get 50% of R!
-
-
- -
-
“None of these surgical masks exhibited adequate filter performance and facial fit characteristics to be considered respiratory protection devices.” Tara Oberg & Lisa M. Brosseau ↩
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- -
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“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.” Milton DK, Fabian MP, Cowling BJ, Grantham ML, McDevitt JJ ↩
-
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- -
-
Any actual scientist who read that last sentence is probably laugh-crying right now. See: p-hacking, the replication crisis) ↩
-
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- -
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“It is time to apply the precautionary principle” Trisha Greenhalgh et al [PDF] ↩
-
-
- -
-
Davies, A., Thompson, K., Giri, K., Kafatos, G., Walker, J., & Bennett, 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. ↩
-
-
- -
-
"We need to save supplies for hospitals." Absolutely agreed. But that's more of an argument for increasing mask production, not rationing. In the meantime, we can make cloth masks. ↩
- -"They're hard to wear correctly." It's also hard to wash your hands according to the WHO Guidelines – seriously, "Step 3) right palm over left dorsum"?! – but we still recommend handwashing, because imperfect is still better than nothing.
- -"It'll make people more reckless with handwashing & social distancing." Sure, and safety belts make people ignore stop signs, and flossing makes people eat rocks. But seriously, we'd argue the opposite: masks are a constant physical reminder to be careful – and in East Asia, masks are also a symbol of solidarity!
-
-
- -
-
“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%. Wang, Jingyuan and Tang, Ke and Feng, Kai and Lv, Weifeng ↩
-
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- -
-
“SARS-specific antibodies were maintained for an average of 2 years [...] Thus, SARS patients might be susceptible to reinfection ≥3 years after initial exposure.” Wu LP, Wang NC, Chang YH, et al. "Sadly" we'll never know how long SARS immunity would have really lasted, since we eradicated it so quickly. ↩
-
-
- -
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“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.” Marta Galanti & Jeffrey Shaman (PDF) ↩
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- -
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“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.” from STAT News by Andrew Joseph ↩
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From Bao et al. Disclaimer: This article is a preprint and has not been certified by peer review (yet). Also, to emphasize: they only tested re-infection 28 days later. ↩
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“If a coronavirus vaccine arrives, can the world make enough?” by Roxanne Khamsi, on Nature ↩
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- -
-
“Don’t rush to deploy COVID-19 vaccines and drugs without sufficient safety guarantees” by Shibo Jiang, on Nature ↩
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- -
-
Dry land metaphor from Marc Lipsitch & Yonatan Grad, on STAT News ↩
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Letalo je potonilo. Naleteli smo na rešilne splave in čas je, da poiščemo kopno.[40]
+Skupine epidemiologov in snovalcev politik (leve, desne in nadstrankarske) so dosegle soglasje o tem, kako premagati COVID-19 in hkrati zaščititi naša življenja ter svoboščine.
+Tukaj je skica ideje z nekaj (manj soglasnimi) rezervnimi načrti:
+
Torej, kaj trenutno to pomeni ZATE?
+Za vse: Spoštujte ukazano karanteno, da bomo lahko takoj stopili iz faze I. Še naprej si umivajte roke, izdelajte si svoje maske, prenesite si aplikacijo za sledenje stikov, ki ščiti zasebnost (ko bo le-ta na voljo v naslednjem mesecu). Ostanite zdravi, tako fizično kot tudi psihično! Svojim krajevnim politikom pa sporočite, da je lenobe dovolj in …
+Za politike: Sprejmite zakone za podporo vsem ljudem, ki so bili prisiljeni v samoizolacijo. Najemite več ročnih sledilnikov stikov, ki jih podpirajo aplikacije za sledenje stikov. Več sredstev usmerite v stvari, ki bi jih morali graditi, kot na primer …
+Za ustvarjalce: Ustvarjajte teste. Ustvarjajte ventilatorje. Ustvarjajte osebno zaščitno opremo za bolnišnice. Ustvarjajte maske. Ustvarjajte aplikacije. Ustvarjajte protivirusna sredstva, preventivna sredstva ter druge načine zdravljenja, ki niso cepiva. Ustvarite teste. Ustvarite teste. Ustvarite teste.
+Ne omalovažujte strahu, da bi povečali vaše upe. Naš strah bi se moral združiti z našim upanjem tako kot izumitelji letal in padal. Priprava na grozno prihodnost nam v bistvu ustvari upanja polno prihodnost.
+Ideja, da nas mora biti strah le strahu samega, je edina, česar se moramo resnično bati.
++
-
+
Te sprotne opombe bodo imele vire, povezave ali dodatne komentarje. Tako kot ta komentar!
+Ta vodič je bil objavljen 1. maja 2020 Številne podrobnosti bodo zastarele, ampak sva prepričana, da bo ta vodič zajel 95% verzij prihodnosti, da bo Uvod v epidemiologijo za vedno ostal uporaben. ↩
+
+“Povprečni [serijski] interval je bil 3.96 dni (95% CI 3.53–4.39 dni)”. Du Z, Xu X, Wu Y, Wang L, Cowling BJ, Ancel Meyers L (Disclaimer: Članki z zgodnjo izdajo se ne štejejo v končne različice) ↩
+
+Ne pozabite: vse te simulacije so v izobraževalne name zelo poenostavljene.
+Ena poenostavitev: Ko ukažete tej simulaciji “Okužite 1 novo osebo vsakih X dni”, se dejansko vsak dan poveča število okuženih za 1 / X. Enako za prihodnje nastavitve v teh simulacijah – “Ozdravi vsakih X dni” dejansko zmanjša število okuženih za 1 / X vsak dan.
+Ti niso popolnoma enaki, ampak so dovolj dober približek, da so zaradi izobraževalnih namenov razumljivejši kot neposredna nastavitev hitrosti prenosa/okrevanja. ↩
+
+“Povprečna doba nalezljivosti […] je bila 9.5 dni.” Hu, Z., Song, C., Xu, C. et al
+
+Ja, vemo, da “mediana” ni isto kot “povprečje”. Za lažje razumevanje zanemarimo razliko. ↩
+Bolj podrobna pojasnitev modela SIR: the Institute for Disease Modeling in Wikipedia ↩
+
+Bolj strokovno razlago modela SEIR najdeš: the Institute for Disease Modeling in Wikipedia ↩
+
+“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, 0.8–3.0 days) before symptom onset”
+(prevod: Domnevno se simptomi pokažejo po 5 dneh, virus pa širiš že 2 dni prej = Nalezljivost se začne 3. dan)
+He, X., Lau, E.H.Y., Wu, P. et al. ↩
+“Srednja vrednost R za sezonsko gripo je znašala 1,28” Biggerstaff, M., Cauchemez, S., Reed, C. et al. ↩
+
+“Osnovno reprodukcijsko število R0 leta 2019-nCoV smo ocenili na približno 2,2 (90-odstoten gost interval: 1,4–3,8)” Riou J, Althaus CL. ↩
+
+“Izračunali smo srednjo vrednost R0 5,7 (95% CI 3,8–8,9)” Sanche S, Lin YT, Xu C, Romero-Severson E, Hengartner N, Ke R. ↩
+
+Pretvarjamo se, da so vsi enako kužni v svojem t.i. “nalezljivem obdobju”. Zaradi izobraževalnih namenov je znova prišlo do manjših poenostavitev. ↩
+
+Pomni: R = R0 *razmerje prenosov, ki so še dovoljeni. Ne pozabite tudi, da je dovoljeno razmerje prenosov = 1 – razmerje ustavljenih prenosov.
+Če želite dobiti R < 1, morate dobiti R0 *
+
DovoljeniPrenosi < 1.Sledi: DovoljeniPrenosi < 1/R0
+Sledi: 1 – UstavljeniPrenosi < 1/R0
+Sledi: UstavljeniPrenosi > 1 – 1/R0
+Zato je potrebno ustaviti več kot 1 – 1/R0 prenosov, da dobimo R < 1 in omejimo virus! ↩
+
+“Odstotek primerov COVID-19 v ZDA od 12. februarja do 16. marca 2020, za katere je bil potreben sprejem na oddelku intenzivne nege (glede na starostno skupino)”. Le ta se je za vse primere COVID-19, ki so potrebovali intenzivno nego, gibal med 4,9% in 11,5%. Če smo pri tem še malenkost velikodušni in tako izberemo spodnjo mejo, ugotovimo, da je to 5% oziroma vsak dvejseti. Upoštevati morate, da je ta vrednost značilna za starostno skupino ZDA ter da bo vrednost v državah s starejšim prebivalstvom višja in nižja v državah z mlajšim prebivalstvom. ↩
+
+“Število ležišč na oddelku za intenzivno nego = 96.596”. Leta 2019 je bilo število prebivalcev ZDA iz družbe za kritično oskrbo (the Society of Critical Care Medicine) enako 328.200.000. 96.596 od 328.200.000 = približno 1 na 3400. ↩
+
+“Pravi, da je dejanski cilj enak kot v drugih državah: zravnati krivuljo s pravo razporeditvijo začetka okužb. Posledično lahko država doseže čredno imunost; je stranski učinek in ne cilj. […] Dejanski akcijski načrt vlade za koronavirus, ki je na voljo na spletu, sploh ne omenja čredne imunosti. ”
+Iz članka The Atlantic article by Ed Yong ↩
+
+“Vseh osem kvalificiranih študij je poročalo, da je pranje rok zmanjšalo tveganje za okužbo dihal, zmanjšanje tveganja pa je znašalo od 6% do 44% [združena vrednost 24% (95% CI 6-40%)].« Zaradi enostavnosti smo v simulacijah združeno vrednost zaokrožili na 25%. Rabie, T. and Curtis, V. Opomba: kot kaže ta meta-analiza, je kakovost študij glede pranja rok (vsaj v državah z visokimi dohodki) grozljiva. ↩
+
+“Ugotovili smo, da se je povprečno dnevno število stikov na udeleženca zmanjšalo za 73%. To bi zadostovalo za zmanjšanje R0 iz vrednosti 2,6 pred zaprtjem na 0,62 (med 0,37 in 0,89) v času zaprtja”. Ponovno smo zaradi enostavnosti v simulaciji vrednost zaokrožili na 70%. Jarvis and Zandvoort et al ↩
+
+Tega izkrivljanja bi se znebili, če bi R risali na logaritmični lestvici… vendar bi potem morali dodatno razložiti še logaritmične lestvice. ↩
+
+“Če ni drugih intervencij, je ključno merilo uspešnosti socialnega distanciranja to, ali so presežene zmogljivosti kritične oskrbe. Da bi se temu izognili, bo morda potrebno dolgotrajno ali občasno distanciranje do leta 2022.” Kissler and Tedijanto et al ↩
+
+Glej sliko 6: Figure 6 from Holt-Lunstad & Smith 2010. Seveda, nedvomno gre za zanikanje pomembne izjave o tem, da so našli korelacijo. Če želite sami poskusiti naključno določiti ljudi, ki naj bodo osamljeni za vso življenje, so vse, kar boste dobili, dokazi o opazovanju. ↩
+
+V povprečju 3 dnevi do stanja nalezljivosti: “Na podlagi ločenih študij zgodnjih primerov COVID-19, domnevamo, da je inkubacijsko obdobje v povprečju porazdeljeno na 5,2 dni in sklepamo, da do nalezljivosti pride že pred pojavom simptomov, in sicer od 2,3. dneva dalje (95% Cl, 0,8-3,0 dni).” (Ob predpostavki, da se simptomi začnejo pri 5 dneh, do nalezljivosti pride že 2 dneva prej = nalezljivost se začne pri 3 dneh) He, X., Lau, E.H.Y., Wu, P. et al.
+V povprečju 4 dnevi, da pride okužba do nekoga drugega: “Povprečni [serijski] interval je bil 3,96 dni (95% Cl 3,53-4,39 dni)” Du Z, Xu X, Wu Y, Wang L, Cowling BJ, Ancel Meyers L
+V povprečju 5 dni, da začutimo prve simptome: “Mediana inkubacijske dobe je bila ocenjena na 5,1 dni (95% Cl, 4,5-5,8 dni)”. Lauer SA, Grantz KH, Bi Q, et al ↩
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+“Ocenili smo, da je bilo 44% (interval zaupanja: 95%, 25-69%) sekundarnih primerov okuženih ravno med predsimptomatsko stopnjo indeksnih primerov.” He, X., Lau, E.H.Y., Wu, P. et al ↩
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+“Sledenje stikov se je v Liberiji izkazalo kot kritično posredovanje in je predstavljajo enega največjih naporov iskanja stikov med epidemijo v zgodovini.” Swanson KC, Altare C, Wesseh CS, et al. ↩
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+Temporary Contact Numbers, decentraliziran protokol sledenja stikov z varnostjo zasebnosti ↩
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Podjetji Apple and Google sodelujeta pri tehnologiji sledenja stikov v zvezi z virusom COVID-19. Pomni, da ne ustvarjajo aplikacij samih, zgolj sisteme, ki jih bodo podpirale. ↩
+
+Veliko novih poročil - iskreno, res veliko - ni razlikovalo med “primeri, ki niso pokazali nikakršnih simptomov, ko smo jih testirali” (pre-simptomatski) in “primeri, ki jih nikdar niso pokazali” (popolnoma asimptomatski). Edini način razlikovanja je poznejše nadoknadenje primerov.
+Kar je točno to, kar je raziskava naredila. V klicnem centru v Južni Koreji, kjer so imeli izbruh virusa COVID-19, “so le štirje (1.9 %) ostali asimptomatski v roku štirinajstih dni karantene in noben od stikov z njihovimi gospodinjstvi ni pripeljal do sekunarnih okužb.”
+To pomeni, da so “popolnoma asimptomatski” redki, okužba od popolnoma asimptomatskega primera pa še redkejša! ↩
+
+Iz iste oxford-ske raziskave, ki je prva predlagala aplikacije za boj proti virusu COVID-19: Luca Ferretti & Chris Wymant et al Glej diagram 2. Če predpostavimo R0 = 2.0, potem velja:
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- Simptomatski prispevajo R = 0,8 (40 %) +
- Pre-simptomatski prispevajo R = 0,9 (45 %) +
- Asimptomatski prispevajo R = 0.1 (5 %, sicer njihov model še ima negotovosti in je lahko R precej nižji.) +
- Okoljski predmeti kot so kljuke prispevajo R = 0.2 (10 %) +
In seštej pre- & a-simptomatske stike (45 % + 5 %) in znaša R 50 %! ↩
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+“Nobena od teh kirurških mask ni pokazala ustreznih lastnosti filtra in obraznega prileganja, da bi jih lahko šteli kot pripomočke za zaščito dihal.” Tara Oberg & Lisa M. Brosseau ↩
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+“Skupno 3,4-kratno zmanjšanje [70 % zmanjšanje] kopirnih števil aerosola, ki smo ga opazovali kombiniranega s skoraj popolno eliminacijo razpršila velikih kapljic, ki je bil demonstriran s strani Johnsona et al., predlaga, da bi kirurške maske, ki jih nosijo okuženi, lahko imele klinično signifikantni prispevek k prenosu.” Milton DK, Fabian MP, Cowling BJ, Grantham ML, McDevitt JJ ↩
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+Vsak dejanski znanstvenik, ki je prebral zadnji stavek, se verjetno trenutno smeje-joče. Glej: p-hacking, kriza podvajanja)
+ ↩
+“Čas je za vpeljavo previdnostnega načela” Trisha Greenhalgh et al [PDF] ↩
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+Davies, A., Thompson, K., Giri, K., Kafatos, G., Walker, J., & Bennett, A Glej seznam 1: 100 % bombažna majica ima okrog 2/3 filtrirne učinkovitosti kirurške maske, kar velja za dva bakterijska aerosola, za katera so testirali. ↩
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+“Prihraniti moramo zaloge za bolnišnice.” Absolutno drži. Toda to je bolj argument za povečanje proizvodnje mask, ne omejevanje količine.
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+Medtem pa si lahko naredimo maske iz tkanin. ↩“Težko jih je nositi pravilno.” Prav tako si je težko umivati roke v skladu s smernicami WHO – resno, "korak 3.) Dlan desne roke preko hrbtišča leve?! – Vseeno še vedno priporočamo umivanje rok, saj je nepopolno še zmeraj bolje kakor nič.
+“Ljudje bodo bolj nepremišljeni pri umivanju rok in socialem distanciranju.” Kakopak! Zaradi varnostnih pasov ljudje tudi ignorirajo stop znake, prav tako zaradi nitkanja ljudje jedo kamenje. Zdaj pa zares, zavzemali bi se za nasprotno: maske so neprestani fizični opomnik, da moramo biti previdni – V Vzhodni Aziji so celo simbol solidarnosti.
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+“Zvišanje temperature za eno stopinjo Celzija […] zniža R za 0,0225” in “Povprečna vrednost R teh 100 mest je 1,83”. 0.0225 ÷ 1.83 = ~1.2%. Wang, Jingyuan and Tang, Ke and Feng, Kai and Lv, Weifeng ↩
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+ “Specifična protitelesa za SARS so se v povprečju ohranila 2 leti […] Zatorej so SARS pacienti morebiti dovzetni za ponovno okužbo po več kot 3 letih po prvotnem izpostavljenju.” Wu LP, Wang NC, Chang YH, et al. “Na žalost” ne bomo nikoli vedeli kako dolgo bi SARS imunost resnično trajala, saj smo se ga znebili tako hitro. +
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+“Nismo našli nikakršne signifikantne razlike med verjetnostjo vsaj enkrat pozitivnega testa in verjetnostjo ponovnega pojava Beta-Corona virusa HKU1 in OC43 34 tednov po prvi okužbi.” Marta Galanti & Jeffrey Shaman (PDF) +
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+“Čim se oseba otrese virusa, se viralni delci še nekaj časa zadržijo v telesu. Ti ne morejo povzročiti okužbe, lahko pa so povzročitelji pozitivnega testa.” from STAT News by Andrew Joseph ↩
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+Od Bao et al. izjava o omejitvi odgovornosti: Ta članek je osnutek in še ni bil pregledan s strani strokovnjakov. Poudariti je treba tudi: testirali so le ponovno okužbo 28 dni pozneje. ↩
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+“Če pride cepivo, ali smo ga sposobni proizvesti dovolj?” by Roxanne Khamsi, on Nature ↩
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+“Ne prehitevajte z razvojem cepiva in zdravil za COVID-19, če zadostna varnost ni zagotovljena” by Shibo Jiang, on Nature ↩
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+Metafora o suhi zemlji from Marc Lipsitch & Yonatan Grad, on STAT News ↩
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