Interesting evidence indicating that R0 might actually be lower than Delta but with some immune evasion that allows it to spread in areas previously hit by Delta:
I'm not really sure R0 is actually a meaningful thing to run a prediction market on. The problem is, when you dig into how R0 is calculated, it's not really a precise or well defined value. In theory its definition is simple enough but in reality, it has no biological basis - claims that R0 is this or that are always coming from models. And when you look at what the models do, well, R0 turns out to just be some kind of fudge factor or arbitrary coefficient used to make the model roughly match the data reported so far.
As a consequence I've seen models that yield totally different values of "R0" for the same virus on the same dates, simply because the model was given case curves from different cities. As such it cannot be genuinely said that this represents anything genuinely true about the virus itself. It's not like it's derived from RNA or careful lab experiments or anything like that.
Many seem to believe there's a case for omicron being *less* lethal than delta, based on near-zero-evidence throwaway quotes being shared widely on social media, best I can tell, out of wishful thinking. A metaculus question opened on this here:
I wish I was smart enough to know wether or not this article means I should be more scared or not. (I'm assuming....yes? Be more scared?). I'm boosted. Does that help or we don't know? #YourDumbestSubscriber
Wait, no FDA approval?! That's outrageous!
There is an interesting article arguing that the models being used for Covid are wrong, mostly because they ignore the structure of a population, the fact that A is much more likely to interact with B and C than with X, Y, and Z who are interacting with each other. He argues that the actual pattern of what has been happening cannot be explained with the current models. One of his conclusions is that the newer variants may not actually be much more infectious than the older.
Spin-off question: Would it be theoretically possible for a variant to be, for all practical purposes, a covid vaccination? So it would be a virus that kills about 1 person in a million, but mostly causes no symptoms or very mild ones -- and confers immunity to covid for the next few months to all who have been infected. And if that's possible, mightn't it be possible to tweak the variant so as to make it so hugely transmissible that everybody gets it, even the animals who can be infected by covid? If that happened, could we truly and permanently get rid of all variants except the benign one?
I'm sure it's very unlikely that such a virus will pop up, but still would like to hear from knowledgeable people whether such a sequence of events could happen if such a virus did appear.
> Metaculus didn’t want to wade in to precise lethality statistics, so they just asked for a yes-or-no answer on whether it would be deadlier than Delta. Forecasters say there’s a 34% chance it will be.
Is that "deadlier on a per case basis", or "deadlier en masse"?
That is, if I catch Delta will I breathing a sigh of relief that at least I didn't get schwacked with something really horrible like Omicron, or is it that way more people will catch Omicron than Delta so Omicron will rack up a higher body count over all by increasing the sheer number of infections?
Because... I'm given to understand that that's how endemic diseases work. It starts off lethal, then millions of millions of generations later the virus finds a sweet spot of being super infectious but relatively chill about killing the host. If Omicron spreads like Gangnam Style but is, say, half as likely to kill you... isn't that a good thing, overall?
Somebody, anybody, feel free to correct me harshly if I'm way off base.
Is the deadliness question about whether it kills more people conditional on their being infected, or just that it kills more people altogether?
Do the prediction markets say anything about how likely it is that Omicron will evade current vaccine protection?
Can I ask when you pulled those graphs? Because the numbers on Metaculus look substantially different now. The median prediction on mortality is now 25%.
Is it reasonable to think:
1) The original covid strain is deadlier than most pathogens (and most coronaviruses)
2) Omicron has more mutations than other variants and is therefore the least like the original strain
3) We should expect reversion to the (less deadly) mean for Omicron which may be more like an average pathogen and less like the original covid variant
4) Therefore, all else being equal, we might expect Omicron to be less deadly?
Of course, all else is probably not equal. Notably, there's reason to believe it would have better vaccine escape, and if it's better at spreading that may be a sign that it has qualities that would make it deadlier. (Better at evading immune response? Better at replicating quickly?) But perhaps there's some reason to think these scary features may be offset by less deadliness otherwise? Maybe that's just wishful thinking, though.
Metaculus says it will resolve the claim based on "the first credible systematic review that estimates this value," citing Liu and Rocklöv (2021) as an example of the sort of thing they consider a “credible review.” But the methodology of Liu and Rocklöv seems atrocious: they write that across five studies they have identified, "the basic reproductive number for Delta ranged from 3.2 to 8, with a mean of 5.08." This has the following problems:
(1) The five studies are one article in English about Guangdong, one article in Chinese about Guangdong, two white papers about the UK, and one MedRxiv preprint about “China”. The five studies all used different methodologies for estimating R0. Liu and Rocklov say nothing about the strengths and weaknesses of these methodologies. Only one of the five studies indicated an explicit confidence interval (95% CI: 2.0–4.8).
(2) The reported “mean of 5.08” is simply the arithmetic mean of the midpoints of the R0 estimates of the five studies. Given the disparity of methodologies, calculating such a mean in the first place seems meaningless, and reporting it to three significant figures is ludicrous. The fact that this went through to publication does not speak well of the peer review process at the “Journal of Travel Medicine”.
(3) It doesn’t even make sense in the first place to talk about “the” R0 for a virus or variant — R0 is a parameter used in certain models for describing the dynamics of a pathogen *in a particular epidemiological situation*. Liu and Roclov half admit this, writing: “Given that the reproductive number in the studies identified here was estimated at a time when most countries still enforce a variable extent of lockdown measures, there is a risk that the real reproductive number may be even higher than the estimated 5.08.” But they fail to realize that the same logic implies that there is no such thing as the “real reproductive number” of a virus: there is only a range of estimated R0 parameters used in various epidemiological models to fit the observed case data in particular times and places.
(Epistemic status: I am not an epidemiologist, and I will be happy if anyone who knows what they are talking about can tell me why I’m wrong.)
I am new to prediction markets as a tool. I understand that Metaculus is probably not Wikipedia, i.e. it's not like a few uninformed but enthusiastic (or informed and malevolent) actors could significantly alter it, but who are the predictors that actually make predictions there?
Kalshi has a yes/no market on whether Omicron will make up over 1% of US COVID infections by the new year:
Currently trading at 71% ”Yes”.
The US federal government has purchased some 2 billion CoViD-19 vaccine doses. Today, the CDC changed their guidance from adults _may_ get a booster to adults _should_ get a booster. This is good, but instead of distributing booster doses to every American who wants one, would it be a more rationally selfish course of action for the US government to distribute those doses to people in the half-dozen countries that the Omicron variant originated from, using the logicstics + medical muscle of the US military?
It sounds like places with large HIV+ (i.e. sort-of-healthy-but-immunocompromised) populations are great places to breed new variants, and it seems infeasible to prevent highly-transmissible new variants from spreading to the rest of the world. So, are our vaccination efforts best spent on places most hospitable to virus breeding?
It wasn't only that the doctor in South Africa noticed young people have less severe disease which would be expected. They also didn't lose their sense of smell and taste which normally happen even with mild covid. It could indicate less severe variant. Of course, it might be just wishful thinking. And yet I don't like so many headlines that it is time to freak out. Especially when we have zero indications that it is more severe either.
While Noah Smith correctly says that restrictions like border closures and other nonpharmaceutical interventions are now useless, politicians and most other people have very little attention span and will only hear the first line “now it is time to panic” and will introduce all of those restrictions again. We should have written the headlines and the first paragraphs differently – something among the lines that omicron is no worse that what we have and banning flights is even less useful, and only then going into details how it works.
I guess the reason that authorities are freaking out about Omicron rather than some other variants is that they have some model of how it will impact human populations based on its genetic structure and the current data on transmission and health. It would be great if they could make this model and assumptions explicit and state what would either confirm or negate this model. Those who disagree could also share their models. Guaranteed we are going to have more scares like this so we need to improve our ability to model their impact based on early evidence otherwise we are going to get Crying Wolf syndrome.
Do we have past evidence that suggests that Metaculus’s users are good at predicting this sort of thing? This isn’t like a political or sports question where there are lots of people out there who possess different subsets of information, such that if we aggregate the data we’ll get the right answer. There really isn’t a lot of data to go on yet, so mostly this is just a bunch of people guessing, and it’s not clear that Metaculus is frequented by the sorts of people who are likely to have meaningful guesses about this…
Prediction: we will reach the Omega Variant, and people will freak the fuck out because of the name.
I don't understand how people settled on R0=2.5 for vanilla covid. It seems much higher to me, given the (much more accurately measurable) serial interval of about 5 days, and case doubling time of 3 days (see e.g. US covid deaths by date in March 2020).
It really disappoints me when otherwise intelligent people are ignorant enough to use twitter.
I HATE posting on Substack. For the second time in 2 days I have spent upwards of 30 mins. writing a long reply, and Substack suddenly swallowed my text before it was quite complete. Yes, I know I could have avoided this infuriating outcome if I'd typed my reply into a text editor on my computer then copy-pasted into Substack, but why do we have to be communicating on a platform that's so fucking poorly set up that we need to fall back on that sort of workaround?
Aren't we getting to the point where enough have been infected that we have natural immunity? And don't the vaccines work A LITTLE BIT to prevent spread? Aren't we getting to endemic soon?
Or maybe the new variants also escape natural immunity?
Or maybe not as many have been infected as I had thought.
I don't know.
Anecdotally, a captured WW2 German communique argued that “it is useless to study the Americans Army manuals, because the Americans don’t read them, and wouldn’t follow them if they did.”
I feel the same way regarding any and all data sets regarding the patterns and behaviors of large groups of people in this day and age. To include data on communicable diseases which you would want “somebody to do something” about. Every single big brained Ivy Leagued nitwit out there has forgotten that human beings are a second order chaotic system. They will change their behavior when they realize they are being observed. A good case study for this is the number of counties in swing states which shifted towards Bush after very concerned UK citizens wrote them letters imploring them to vote for John Kerry.
TL;DR- Put a sock in it with these charts and such. It’s not helpful.
For some reason doing this with predicttion markets feels a little scuzzy. I suppose it feels too much like "lay, your bets, how many people will die?" Obviously prediction markets could have grear utility but I feel like the way its presented here is a little too cavalier/gleeful.
Potentially stupid question - is there a reason that there have not yet been any recorded deaths from the Omicron variant? Is this normal with new variants of diseases/is there typically a lag of a few months before deaths start to show up?
I've seen articles like this one:
talking about the increase in excess deaths, but that is not at all a clear indicator that Omicron is running rampant through South Africa - again, mostly because no one who has been diagnosed with it has died according to the WHO.
What is happening here?