20 ms·

Covid-19 twice as contagious as previously thought – CDC study

264 points by deegles 7y ago

chickenpotpie 7y ago
Can anyone explain how the virus is twice as infectious as we thought, but we're consistently lowering our death projections everyday?
- unsrsly 7y ago
  The R is a function of human behavior, so sheltering in place lowers it (ideally below 1) which also reduces deaths in the future.
  - williamstein 7y ago
    E.g., from the article: "Dr Feigl-Ding explains that R0 is the “R reproductive number at time 0 before countermeasures”. He points out that this is not the R(effective) at current time under mitigation measures such as distancing and testing, tracing and quarantine, which are expected to slash chains of transmission."
    - fspeech 7y ago
      R0 is also culture dependent but before countermeasures are applied.
    - unsrsly 7y ago
      Thanks for adding that. Interestingly, Eric Feigl-Ding is a bit like Nicholas Christakis in that he is not an expert in infectious diseases, however he has positioned himself as an expert on COVID19. This seems to have annoyed some of the real experts like Marc Lipsitch. However, Feigl-Ding probably does deserve some credit for sounding the alarm relatively early on COVID19.
      - empath75 7y ago
        The real experts were all saying ‘it’s too early to say for sure’ and he was saying, yes, but the worst case scenario is really bad and everyone should know that.
  - makomk 7y ago
    Higher R0 should reduce the effectiveness of measures like social distancing, shelter-in-place, etc too though - those work by reducing the number of people each infected person interacts with, but if those interactions are more likely to spread the disease than previously estimated the eventual R you end up with is going to be higher than expected too.
    - jkhdigital 7y ago
      Exactly, like HIV started with a high R0 but its transmission mechanism is pretty easy to get a handle on--don't have unprotected sex or donate blood. Once this information is widely known, BAM, low R0. SARS-CoV-2 is quite a different beast, and reducing the R0 might be a hell of a lot more difficult.
      - nradov 7y ago
        There is no HIV risk in donating blood. The risk was in receiving blood transfusions, before blood banks started doing HIV testing.
- tunesmith 7y ago
  Wouldn't it mean that physical distancing was even more effective than we thought?
- jboggan 7y ago
  Because the IHME model is based on taking China's data at 100% face value and applying it to the US. It over-predicts in the short term and under-predicts in the medium to long term. They keep revising the overall number down to line up with an epidemic peak in 3-4 days in the US, which is ridiculous.
  - btilly 7y ago
    The reason why the epidemic peak is estimated so soon is that New York has the bulk of the cases and they began bringing new cases under control before most of the rest of the nation. Dig into state by state numbers and most states are after that with lower peaks. See https://covid19.healthdata.org/united-states-of-america https://covid19.healthdata.org/united-states-of-america and then https://covid19.healthdata.org/united-states-of-america/new-york https://covid19.healthdata.org/united-states-of-america/new-... to verify.
    - fyp 7y ago
      Does anyone else think NY called their peak prematurely? It seems like there's some periodicity in the data and there's always a slight two day drop every 7 days. This makes sense since many people are still working mon-fri in the city. This is for NYC specifically (last few days of data are incomplete): https://www1.nyc.gov/site/doh/covid/covid-19-data.page https://www1.nyc.gov/site/doh/covid/covid-19-data.page I wouldn't be surprised if NY continued surging in the coming days.
      - deleted 7y ago
        [deleted]
      - a9h74j 7y ago
        Also, I wonder, could there be any effect of a population decrease from an exodus from NYC?
    - marvin 7y ago
      So the assumption here is that New York will be the last big outbreak in the US.
- FPGAhacker 7y ago
  Taking your post at face value, I would say we know it’s twice as infectious due to more testing and/or better data. So we know that more people have been infected. We didn’t discover a bunch of dead people that were infected. So the denominator increased relative to the numerator. Not stating this as fact.
  - jkhdigital 7y ago
    The preprint of this article was published on Feb 7th: https://www.medrxiv.org/content/10.1101/2020.02.07.20021154v1.full.pdf https://www.medrxiv.org/content/10.1101/2020.02.07.20021154v... The authors of this study are almost certainly not the only ones who "knew" it was twice as infectious based only on the data available back in early February, before anyone outside of China was testing at all.
- lindenksv85 7y ago
  Being highly infectious is one thing but a virus’s deadliness is another. Something can have a really high infectiousness rate but not be very deadly, like common cold. The infectiousness they are citing her is the infectiousness that exists under normal conditions. So if you social distance, you can lower the infectiousness. Projected death rates are going down because distancing is working and we are lowering the virus’s infectiousness.
  - xienze 7y ago
    > because distancing is working Really? Because all I’ve been hearing for weeks is nonstop complaining about how the US started social distancing measures way too late, how no one is taking it seriously, etc.
    - tunesmith 7y ago
      That's not a counterpoint, though. That can all be true at the same time as it being true that the situation could be a heck of a lot worse right now.
- jariel 7y ago
  "but we're consistently lowering our death projections every day?" 'The first casualty if war is the Truth'. Whatever the government tells you during a time of crisis is a form of propaganda, 'for your own good' so to speak. Even if individuals are intelligent, crowds are not. Whatever they say is very calculated and controlled, as if to achieve a specific outcome. So imagine a very cynical view of political messaging in normal times, but now tilt that towards a more truly civic situation wherein maybe it doesn't seem quite so cynical because, well, there is actually a crisis. The 'numbers' projected a few weeks ago will have been constrained by a) what people could handle without panicking, b) what kind of numbers might get them to actually behave properly, c) what will save every political leaders skin (i.e. give bad news then everything after that seems like good news), d) how much we can bend reality without hurting their own credibility by being perceived as lying. It's extremely hard and politically risky to 'shut down a country' and get millions of individual actors to 'buy-in' to behave as we want especially if it means annoyance or personal hardship. Political leaders are used to acting in a very populist way, and basically right now they are doing the extreme opposite. Every day, politicians have to act against their best populist instincts. It's hard to overstate what a sensitive time this is, it could go sour very quickly. So take everything with a grain of salt, knowing that whatever is being said is calculated and 'all projections' are filtered somewhat. Ostensibly 'for our own good'. I think there are often more qualified numbers published out there, but you have to go right to the source, if available. Edit: the 'masks' PR and policy is probably the best example of that. In reality, there's not much harm, and likely a little bit of good that can come from masks. But the strategy was to get PPE to the front-line health workers who have a greater need and were in a real crisis, so, the public messaging was 'no masks'. But the 'truth' of masks started to creep to the fore, more were asking questions, moreover, the PPE situation started to stabilize a little bit and 'poof' all of a sudden 'masks are good'. Now they are telling us? The Canadian Chief Medical Officer literally did a 180 on that, sounding a lot like Donald Trump in his total about turns. The communications strategy early on was fairly clear and it made sense, but it's a little uncomfortable to see your so-called leaders only make decisions 'after everyone else' so as to avoid taking and risky or blame (Canada wouldn't budget on it until most other countries did first). If you read the fairly confident communications about masks from several weeks ago and compare them to the messaging now - you see a problem that very only makes sense in the context of "purposeful misdirection for the 'public good' ". Masks did not 'get safer' and nor did our understanding of them change. What changed was who ostensibly needed them the most.
- nullc 7y ago
  > Can anyone explain how the virus is twice as infectious as we thought, but we're consistently lowering our death projections everyday? This article is talking about R0-- a measure of contagion without considering interventions like increasing mask wearing, quarantines, or physical distancing. The higher the R0 the harder we have to work to push the effective R below 1, as is required to stop the spread... and the wider and faster the spread will be if we don't mitigate it.
- guscost 7y ago
  One explanation is that >50% of people have already caught it.
tunesmith 7y ago
I've seem people theorize about this before saying maybe it's good news because that means it's less fatal than we thought and therefore maybe we're closer to herd immunity. But I saw an epidemiologist talk about how an R0 of 2 meant you needed 50% of people to be immune for herd immunity, and an R0 of 3 meant you needed 66%. This would mean it'd need to be even higher - the article says 82%. We're nowhere close to that now - even northern Italy, they're estimating that maybe 10% have caught it.
- hprotagonist 7y ago
  yes, this is why measles vaccination rates must be nearly total. measles has an R_0 somewhere beteween 14 and 18 (!!!)
  - greglindahl 7y ago
    A second is that the measles vaccine fails more often than many others. The combination drives the necessary vaccination rate quite high, and the risk isn't just the unvaccinated kids, it's a % of the ones who thought they were fully vaccinated.
- roel_v 7y ago
  Also, it seems that people with low severity symptoms don't build up a lot of antibodies, so they're not sufficiently immune. So out of that 10%, only some count towards the herd.
  - ztjio 7y ago
    Citation?
    - sroussey 7y ago
      From the last sentence in the conclusion: "Stronger antibody response was associated with delayed viral clearance and disease severity." https://www.medrxiv.org/content/10.1101/2020.03.24.20042382v1.full.pdf https://www.medrxiv.org/content/10.1101/2020.03.24.20042382v...
pjkundert 7y ago
Finally, getting some decent data! This means that “herd immunity “ is a non-starter: natural immunity through infection/recovery requires large fractions of the high-risk population to be infected, and vaccines are too far out (economic destruction would occur before vaccines may exist). We must pursue large-scale testing on a “total war” basis, with the goal of containment and extinguishing the virus.
- jonplackett 7y ago
  Herd immunity was a non-started way before this. Just based on death rate it's an insane strategy. Even if the death rate is 1%, then in the USA, to have even 60% infected and recover, you need to have 192 million infected. 1% death rate = nearly 2 million dead. But it would be way higher than 1% death rate with these sort of numbers because most of these people are not even getting a hospital bed, never mind ICU.
  - k__ 7y ago
    Didn't a study show that the death rate is a magnitude lower than previously thought? Something like 0,6% IIRC.
    - deviantfero 7y ago
      even if the death rate is that low, you have to account for the fact that health systems in first world countries are overloading with the initial stages of the spread, leading to more people dying because there's no medical attention to patients who would otherwise make it through the disease.
      - jonplackett 7y ago
        In Italy they have 10% of people who they know have the virus dying (deliberately not calling this death rate) but they are testing pretty well and that seems very, very high. Can there be 10X more people with the virus than they know about? Not sure. Also, OK let's call it 0.6%. Only just over a million deaths in the US alone then, even before health systems overwhelmed. Still a non-starter in my book.
klenwell 7y ago
Here's an early estimate graphed by the NY Times at the end of February (scroll down a bit): https://www.nytimes.com/interactive/2020/world/asia/china-coronavirus-contain.html#virulence https://www.nytimes.com/interactive/2020/world/asia/china-co... R0 estimated to be 2 - 4. Fatality rate: 0.1 - 3%. This was the first information I saw that helped me understand why this was more than just a bad flu. Still didn't truly understand it at that point, at least the way I do now that we're experiencing the consequences of failing to contain it.
- snapetom 7y ago
  In pre-print on Feb 7, this paper initially estimated R0 to be somewhere between 4.7 and 6.6. People dismissed it as being not possible. It was never picked up by the MSM. Now we're seeing from the both the real world and other studies that it's pretty plausible.
  - jkhdigital 7y ago
    Yep, I read the preprint as soon as it was published and it scared me into buying masks back in mid-February.
    - snapetom 7y ago
      Basic math, knowing population density, and then that paper was my "oh shit" moment. Got some half respirators and 300 rolls of toilet paper over the next week. The toilet paper wasn't to prepare for a post-apocalyptic world. It was because I knew that was the first thing other idiots would buy when news of this thing hit your average Joe :)
      - DoofusOfDeath 7y ago
        Perhaps I'm misunderstanding your point, but it sounds like your bragging about being the first person to start hoarding.
  - squidproquo 7y ago
Animats 7y ago
Stanford just tested 3200 people in Silicon Valley for antibodies at a drive-through location.[1] There are similar group tests being run in LA and Colorado. In a few days there should be more solid info on how many people have had the disease without symptoms. [1] https://www.stanforddaily.com/2020/04/04/stanford-researchers-test-3200-people-for-covid-19-antibodies/ https://www.stanforddaily.com/2020/04/04/stanford-researcher...
- droidist2 7y ago
  Seems promising! I really hope it's a couple days though and not weeks like the usual coronavirus testing I've been hearing about.
  - girvo 7y ago
    The tests here in Queensland give results in 24 hours, according to a friend who was just tested
    - droidist2 7y ago
      That's not bad. In the US my friend just got tested and they said 5-10 business days.
  - deelowe 7y ago
    IIRC, the researchers stated yesterday not to expect any surprises based on what they've found so far... :(
  - maxerickson 7y ago
    The test takes 10 minutes: https://premierbiotech.com/innovation/covid-19/ https://premierbiotech.com/innovation/covid-19/ They're talking about it being a few days before they release the statistics from the testing.
- elliekelly 7y ago
  (As someone who knows next to nothing about medicine or microbiology) I’m curious how they already know which antibodies to look for? Are antibodies unique to each virus? Is it possible that some people have stumbled upon antibody X at some point in their lives that maybe isn’t perfect for fighting off this new coronavirus but still helps? Along the same lines, is it possible some people have antibodies IgM and IgG from some other illness they’ve encountered in their lives? Or is the presence of those antibodies conclusive evidence that they’ve been infected with COVID-19?
fspeech 7y ago
The actual article that is both readable and informative https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article
mrtweetyhack 7y ago
According to WHO and China, there is no Covid-19
thisrod 7y ago
This seems a bit odd. If it was my job to estimate R₀ for the coronavirus, I'd look at Singapore, Korea, Australia, New Zealand and so on, where there are thousands of patients, and almost all of them know when they caught it and who they caught it from. Why would you choose to study a place where people don't know those things?
- fspeech 7y ago
  Because that is the definition of R0. Once people are aware and change their behavior R changes as well and is not readily translatable to a different setting.
  - foogazi 7y ago
    So you want to measure transmission rates under normal interactions, not during shelter in place/everyone wearing masks?
    - eneveu 7y ago
      Yes. From the article: Dr Feigl-Ding explains that R0 is the “R reproductive number at time 0 before countermeasures”. He points out that this is not the R(effective) at current time under mitigation measures such as distancing and testing, tracing and quarantine, which are expected to slash chains of transmission.
- deleted 7y ago
  [deleted]
ggm 7y ago
I will repeat a question I would love an epidemiologist to reply to: Where is the random background testing? Not testing "I feel unwell" presentations at random, truly going into the field and testing the wider population at random, healthy (believed) or not? You cannot model the IFR accurately from skewed samples and it feels like we aren't even doing skewed sampling.
- nitrobeast 7y ago
  I believe Wuhan government eventually went door-to-door to test the population exhaustively.
- starpilot 7y ago
  It's in South Korea where there is an abundance of tests. Where tests or people to administrate them are scarce, we have to prioritize those with symptoms.
  - sooheon 7y ago
    There is an argument to me made for the exact opposite. Those who are already sick will be treated according to their symptoms, a diagnosis has little bearing on the treatment they will receive and therefore low value. Meanwhile, proper random sampling of the population will give more accurate prevalence numbers and trends, allowing for much better epidemic response. South Korea (and Singapore and HK etc.) had a specific policy of contact tracing instead of random sampling, which works if you start it early enough and can actually keep ahead of suspected contact spread.
    - Skunkleton 7y ago
      Sick people should be tested when they require medical intervention as it guides their care. It would be a shame to assume COVID when it might be something treatable.
      - sooheon 7y ago
        I'm sure the decision tree is complex, and there are branches where what you say is absolutely true. However, given the testing kit bottleneck, if identification of "something treatable" is crucial, it might be better to test for those treatable diseases that are likely given presenting symptoms. In the extreme case, if you require a ventilator right now or you'll die, nobody needs to wait on verification of the specific viral cause to begin treatment.
deleted 7y ago
[deleted]
yters 7y ago
Twice as contagious = half as deadly?
- DesiLurker 7y ago
  depends on the death lag, if you are in the exponential growth stage of the outbreak that it.
- guscost 7y ago
  Much, much less than half. Contagiousness affects the exponential spread.
  - yters 7y ago
    So maybe cov2 is on level with the flu after all.
    - guscost 7y ago
      I’m not a doctor, but I’d bet it’s closer to a cold - it spreads much faster, but may be less lethal. Also, when a virus jumps between species, its virulence can be elevated during the initial period of spread. So it might be a “really bad” cold, at least early on: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4361674/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4361674/
      - yters 7y ago
        I wonder why such panic then.
        guscost 7y ago
        If it's really not that bad, I would guess that the panic is because this is the first time we've been able to observe a brand-new cold virus as it spreads around the world. When the general public starts to understand all of the damage that these things do, and how quickly they can spread, it's understandably pretty scary. Plus a whole bunch of other factors.
bwandu 7y ago
thinkpol doesn't appear to be a reliable canadian media outlet r/fuckthinkpol for stickied thread shows what type of people are behind it
mmmrtl 7y ago
Title correction: this isn't a CDC study, just published in a CDC journal
- Scipio_Afri 7y ago
  I think they're pretty reputable, regardless. "Author affiliations: Los Alamos National Laboratory, Los Alamos, New Mexico, USA"
- Scipio_Afri 7y ago
  Also the Bios of a couple of the authors at the end: "Dr. Sanche is a postdoctoral research associate at Los Alamos National Laboratory, Los Alamos, New Mexico, USA. His primary research interest lies in complex disease dynamics inferred from data science and mathematical modeling. Dr. Lin is also a postdoctoral research associate at Los Alamos National Laboratory. His primary research interest lies in applied stochastic processes, biological physics, statistical inference, and computational system biology."
Medicalidiot 7y ago
Here's the study from the Diamond Princess which elucidates what the percentage of the population is asymptomatic: https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2020.25.10.2000180 https://www.eurosurveillance.org/content/10.2807/1560-7917.E...
w3mmpp 7y ago
So, let me get this straight, we stopped the world economy because of mitigation actions based on a R0 of 2 and, it ends up, the R0 is almost 6 which make those same mitigations actions completely inadequate? Well, if I was one of those scientists I'll start looking for another career right now, one that doesn't have anything to do with numbers, because it's the blunder of the century right there. Edit: the blunder I'm talking here is by the scientists that have been telling us R was between 2 to 3 for months.
- analog31 7y ago
  Anecdote: At my workplace, the people who were the most concerned about the adequacy of mitigation actions were the scientists. We stopped the world economy based on scientists begging for strong measures, and getting weak measures instead.
  - w3mmpp 7y ago
    Do you call what we have now weak measure? The whole economy is shut, what more do you want?
    - deegles 7y ago
      In Wuhan they were welding apartment building doors shut, and the government was delivering food. There were drones flying around telling people to go home. There are videos of people being forcefully dragged home. None of the current "it's ok to go out and exercise and buy groceries," which is what is currently happening in NYC. So yeah there are further measures available.
      - w3mmpp 7y ago
        Whole generations of people have been killed for freedom and you're ready to give it all back for a 1% fatality rate? It's a bad bargain imo.
        fragsworth 7y ago
AzzieElbab 7y ago
If that is true China cases will sky rocket again this month.
cryptonector 7y ago
Excellent. The faster it moves through, the sooner we'll get back to work.
- tunesmith 7y ago
  You've got to do the math on that. Estimate the percentage of people that have caught it. Then compare that to how 82% people need to catch it in order to have the bare minimum of herd immunity. And factor in that health systems in many regions are already overwhelmed. If you want to get to herd immunity just from catching it, you'd have a health disaster that is impossible to imagine even now.
  - aaron695 7y ago
    I suspect in 2 years time the death toll will be about the same for everyone. What we will look at is how countries handled society while it happened. This 'overwhelmed' the system is a deadly meme, the numbers don't work out. The best model might be wear masks, physical distance, keep hands clean, testing and tracing. Ban really large events.
    - tunesmith 7y ago
      I don't see how you can say the numbers don't work out, unless you believe hospital systems are lying when they say they run out of beds/equipment.
      - aaron695 7y ago
        Try to work out the actual numbers for strict lockdown vs not strict and model it over two years being practical. No hand waving. Include the second and third waves for instance. You won't see the difference you think. Vaccines may never happen ( but post a second winter is a best case ) and treatments don't make things much better. Once you get 1000000 dead vs 1050000 two years later we can talk about the additional dead from being unable to do things like cancer surgery.
tjansen 7y ago
There are plenty of anecdotal stories that show that it spreads very quickly. A highly publicized story in Germany was about one of the first ten cases here. This guy merely sat behind a patient and got asked for a salt shaker. That was his only contact. And I know of a company where someone who returned from a vacation in Italy was in a meeting with 6 people. 5 of them got infected.
anovikov 7y ago
No one thought that it depends on people's habits, say common social norms? Say in Asia it was commonplace to wear masks even before epidemic and it is considered polite to stand far away from one another, and people bow instead of shaking hands. Quite clearly there, or say in Sweden with their tradition of having a large privacy distance, R0 is much lower than in Italy where people hug and kiss seeing each other.
LatteLazy 7y ago
If people weren't dying, it would be hilarious had badly understood this epidemic is. Months since the start, we have no idea how infectious the virus is, how many people have been infected, how deadly it is, how effective (or not) containment is, how many people will need to be hospitalised or how long for. It's actually incredible. I'm very cynical, but I wouldn't have believed Western governments could have floundered so badly if I'd been told even a month ago...
- tbihl 7y ago
  It doesn't help that they leaned heavily on Chinese numbers. Even with data from southern Europe that is likely to be more accurate, people relied on numbers coming out of China because they were early and more numerous... But not enough thought given to openness, and now we've been trying to correct interpolations and extrapolations with a fraudulent starting point for the past two months.
  - LatteLazy 7y ago
    China causing this should be a massive scandal. China lying about their numbers so we can't deal with it effectively should be second bigger scandal. Historically, I've been quite pro China (until they started rounding up Muslims recently at least). But this is totally unacceptable. </rant>...
- majewsky 7y ago
  Do you have any counterexamples where novel germs or viruses were better understood in a shorter amount or time? From my POV, it just looks like a genuinely hard problem right now.
  - LatteLazy 7y ago
    I wouldn't dispute its hard. I don't think coronavirus has any comparative example. Nothing this contagious/disruptive has occurred in modern times. I just find it amazing that we're 6(?) months since the first diagnosis, and we know so so little. Maybe that's life, but maybe if China was honest or the US got its testing together we would not be here?
guscost 7y ago
And now we wait for the other shoe to drop: serosurveys showing that at least one-third of the US population has already caught COVID-19 and recovered.
bbeez 7y ago
I hear a lot about how we may be seriously underestimating the CFR denominator, due to undiagnosed mild cases. Ok I get that. What I don’t hear much about is that the numerator is also probably understated at any point in time for several reasons. First I don’t trust the China data I think it’s understated and that’s the oldest, most mature data we have. Second, in an exponentially growing disease with something like a 6 week course from infection through to mortality/recovery, we will always have diagnosed cases that are 6 weeks, or whatever the true course is, ahead of the final death tally and as the diagnosed cases are rising so rapidly, including those weeks and weeks worth of diagnosed but unresolved cases could add up to a huge amount of error to a simple deaths/cases CFR analysis that would significantly understate what the final CFR will look like. Cohort analysis does not appear to have caught on in the CFR calculation world from what I’ve been reading. Third, I’ve read that there are likely a significant number deaths that are probably attributable to COVID-19 that are not being counted as Covid-19. The death rate in northern Italy over the last month, even when all the COVID-19 attributed deaths are removed, is significantly higher than it has been in similar periods in the past I have read. I believe the same is true in New York City. So if these stories are correct, there are likely more COVID-19 deaths than are being counted. So while it is probably true that the denominator is understated, it seems to me that it’s also very likely true that the numerator is also understated making it very difficult for me to believe any of these estimates are very accurate until both these issues are addressed. Has anyone seen anything that explains some of these issues and calculates a cohort-based death rate, which somehow estimates or adjusts were incorrect, time shifted or under counted Fatality data?

264 points by deegles 7y ago

Can anyone explain how the virus is twice as infectious as we thought, but we're consistently lowering our death projections everyday?

unsrsly 7y ago
The R is a function of human behavior, so sheltering in place lowers it (ideally below 1) which also reduces deaths in the future.
- williamstein 7y ago
  E.g., from the article: "Dr Feigl-Ding explains that R0 is the “R reproductive number at time 0 before countermeasures”. He points out that this is not the R(effective) at current time under mitigation measures such as distancing and testing, tracing and quarantine, which are expected to slash chains of transmission."
  - fspeech 7y ago
    R0 is also culture dependent but before countermeasures are applied.
  - unsrsly 7y ago
    Thanks for adding that. Interestingly, Eric Feigl-Ding is a bit like Nicholas Christakis in that he is not an expert in infectious diseases, however he has positioned himself as an expert on COVID19. This seems to have annoyed some of the real experts like Marc Lipsitch. However, Feigl-Ding probably does deserve some credit for sounding the alarm relatively early on COVID19.
    - empath75 7y ago
      The real experts were all saying ‘it’s too early to say for sure’ and he was saying, yes, but the worst case scenario is really bad and everyone should know that.
- makomk 7y ago
  Higher R0 should reduce the effectiveness of measures like social distancing, shelter-in-place, etc too though - those work by reducing the number of people each infected person interacts with, but if those interactions are more likely to spread the disease than previously estimated the eventual R you end up with is going to be higher than expected too.
  - jkhdigital 7y ago
    Exactly, like HIV started with a high R0 but its transmission mechanism is pretty easy to get a handle on--don't have unprotected sex or donate blood. Once this information is widely known, BAM, low R0. SARS-CoV-2 is quite a different beast, and reducing the R0 might be a hell of a lot more difficult.
    - nradov 7y ago
      There is no HIV risk in donating blood. The risk was in receiving blood transfusions, before blood banks started doing HIV testing.
tunesmith 7y ago
Wouldn't it mean that physical distancing was even more effective than we thought?
jboggan 7y ago
Because the IHME model is based on taking China's data at 100% face value and applying it to the US. It over-predicts in the short term and under-predicts in the medium to long term. They keep revising the overall number down to line up with an epidemic peak in 3-4 days in the US, which is ridiculous.
- btilly 7y ago
  The reason why the epidemic peak is estimated so soon is that New York has the bulk of the cases and they began bringing new cases under control before most of the rest of the nation. Dig into state by state numbers and most states are after that with lower peaks. See https://covid19.healthdata.org/united-states-of-america https://covid19.healthdata.org/united-states-of-america and then https://covid19.healthdata.org/united-states-of-america/new-york https://covid19.healthdata.org/united-states-of-america/new-... to verify.
  - fyp 7y ago
    Does anyone else think NY called their peak prematurely? It seems like there's some periodicity in the data and there's always a slight two day drop every 7 days. This makes sense since many people are still working mon-fri in the city. This is for NYC specifically (last few days of data are incomplete): https://www1.nyc.gov/site/doh/covid/covid-19-data.page https://www1.nyc.gov/site/doh/covid/covid-19-data.page I wouldn't be surprised if NY continued surging in the coming days.
    - deleted 7y ago
      [deleted]
    - a9h74j 7y ago
      Also, I wonder, could there be any effect of a population decrease from an exodus from NYC?
  - marvin 7y ago
    So the assumption here is that New York will be the last big outbreak in the US.
FPGAhacker 7y ago
Taking your post at face value, I would say we know it’s twice as infectious due to more testing and/or better data. So we know that more people have been infected. We didn’t discover a bunch of dead people that were infected. So the denominator increased relative to the numerator. Not stating this as fact.
- jkhdigital 7y ago
  The preprint of this article was published on Feb 7th: https://www.medrxiv.org/content/10.1101/2020.02.07.20021154v1.full.pdf https://www.medrxiv.org/content/10.1101/2020.02.07.20021154v... The authors of this study are almost certainly not the only ones who "knew" it was twice as infectious based only on the data available back in early February, before anyone outside of China was testing at all.
lindenksv85 7y ago
Being highly infectious is one thing but a virus’s deadliness is another. Something can have a really high infectiousness rate but not be very deadly, like common cold. The infectiousness they are citing her is the infectiousness that exists under normal conditions. So if you social distance, you can lower the infectiousness. Projected death rates are going down because distancing is working and we are lowering the virus’s infectiousness.
- xienze 7y ago
  > because distancing is working Really? Because all I’ve been hearing for weeks is nonstop complaining about how the US started social distancing measures way too late, how no one is taking it seriously, etc.
  - tunesmith 7y ago
    That's not a counterpoint, though. That can all be true at the same time as it being true that the situation could be a heck of a lot worse right now.
jariel 7y ago
"but we're consistently lowering our death projections every day?" 'The first casualty if war is the Truth'. Whatever the government tells you during a time of crisis is a form of propaganda, 'for your own good' so to speak. Even if individuals are intelligent, crowds are not. Whatever they say is very calculated and controlled, as if to achieve a specific outcome. So imagine a very cynical view of political messaging in normal times, but now tilt that towards a more truly civic situation wherein maybe it doesn't seem quite so cynical because, well, there is actually a crisis. The 'numbers' projected a few weeks ago will have been constrained by a) what people could handle without panicking, b) what kind of numbers might get them to actually behave properly, c) what will save every political leaders skin (i.e. give bad news then everything after that seems like good news), d) how much we can bend reality without hurting their own credibility by being perceived as lying. It's extremely hard and politically risky to 'shut down a country' and get millions of individual actors to 'buy-in' to behave as we want especially if it means annoyance or personal hardship. Political leaders are used to acting in a very populist way, and basically right now they are doing the extreme opposite. Every day, politicians have to act against their best populist instincts. It's hard to overstate what a sensitive time this is, it could go sour very quickly. So take everything with a grain of salt, knowing that whatever is being said is calculated and 'all projections' are filtered somewhat. Ostensibly 'for our own good'. I think there are often more qualified numbers published out there, but you have to go right to the source, if available. Edit: the 'masks' PR and policy is probably the best example of that. In reality, there's not much harm, and likely a little bit of good that can come from masks. But the strategy was to get PPE to the front-line health workers who have a greater need and were in a real crisis, so, the public messaging was 'no masks'. But the 'truth' of masks started to creep to the fore, more were asking questions, moreover, the PPE situation started to stabilize a little bit and 'poof' all of a sudden 'masks are good'. Now they are telling us? The Canadian Chief Medical Officer literally did a 180 on that, sounding a lot like Donald Trump in his total about turns. The communications strategy early on was fairly clear and it made sense, but it's a little uncomfortable to see your so-called leaders only make decisions 'after everyone else' so as to avoid taking and risky or blame (Canada wouldn't budget on it until most other countries did first). If you read the fairly confident communications about masks from several weeks ago and compare them to the messaging now - you see a problem that very only makes sense in the context of "purposeful misdirection for the 'public good' ". Masks did not 'get safer' and nor did our understanding of them change. What changed was who ostensibly needed them the most.
nullc 7y ago
> Can anyone explain how the virus is twice as infectious as we thought, but we're consistently lowering our death projections everyday? This article is talking about R0-- a measure of contagion without considering interventions like increasing mask wearing, quarantines, or physical distancing. The higher the R0 the harder we have to work to push the effective R below 1, as is required to stop the spread... and the wider and faster the spread will be if we don't mitigate it.
guscost 7y ago
One explanation is that >50% of people have already caught it.

tunesmith 7y ago

I've seem people theorize about this before saying maybe it's good news because that means it's less fatal than we thought and therefore maybe we're closer to herd immunity. But I saw an epidemiologist talk about how an R0 of 2 meant you needed 50% of people to be immune for herd immunity, and an R0 of 3 meant you needed 66%. This would mean it'd need to be even higher - the article says 82%. We're nowhere close to that now - even northern Italy, they're estimating that maybe 10% have caught it.

hprotagonist 7y ago
yes, this is why measles vaccination rates must be nearly total. measles has an R_0 somewhere beteween 14 and 18 (!!!)
- greglindahl 7y ago
  A second is that the measles vaccine fails more often than many others. The combination drives the necessary vaccination rate quite high, and the risk isn't just the unvaccinated kids, it's a % of the ones who thought they were fully vaccinated.
roel_v 7y ago
Also, it seems that people with low severity symptoms don't build up a lot of antibodies, so they're not sufficiently immune. So out of that 10%, only some count towards the herd.
- ztjio 7y ago
  Citation?
  - sroussey 7y ago
    From the last sentence in the conclusion: "Stronger antibody response was associated with delayed viral clearance and disease severity." https://www.medrxiv.org/content/10.1101/2020.03.24.20042382v1.full.pdf https://www.medrxiv.org/content/10.1101/2020.03.24.20042382v...

pjkundert 7y ago

Finally, getting some decent data! This means that “herd immunity “ is a non-starter: natural immunity through infection/recovery requires large fractions of the high-risk population to be infected, and vaccines are too far out (economic destruction would occur before vaccines may exist). We must pursue large-scale testing on a “total war” basis, with the goal of containment and extinguishing the virus.

jonplackett 7y ago
Herd immunity was a non-started way before this. Just based on death rate it's an insane strategy. Even if the death rate is 1%, then in the USA, to have even 60% infected and recover, you need to have 192 million infected. 1% death rate = nearly 2 million dead. But it would be way higher than 1% death rate with these sort of numbers because most of these people are not even getting a hospital bed, never mind ICU.
- k__ 7y ago
  Didn't a study show that the death rate is a magnitude lower than previously thought? Something like 0,6% IIRC.
  - deviantfero 7y ago
    even if the death rate is that low, you have to account for the fact that health systems in first world countries are overloading with the initial stages of the spread, leading to more people dying because there's no medical attention to patients who would otherwise make it through the disease.
    - jonplackett 7y ago
      In Italy they have 10% of people who they know have the virus dying (deliberately not calling this death rate) but they are testing pretty well and that seems very, very high. Can there be 10X more people with the virus than they know about? Not sure. Also, OK let's call it 0.6%. Only just over a million deaths in the US alone then, even before health systems overwhelmed. Still a non-starter in my book.

klenwell 7y ago

Here's an early estimate graphed by the NY Times at the end of February (scroll down a bit): https://www.nytimes.com/interactive/2020/world/asia/china-coronavirus-contain.html#virulence https://www.nytimes.com/interactive/2020/world/asia/china-co... R0 estimated to be 2 - 4. Fatality rate: 0.1 - 3%. This was the first information I saw that helped me understand why this was more than just a bad flu. Still didn't truly understand it at that point, at least the way I do now that we're experiencing the consequences of failing to contain it.

snapetom 7y ago
In pre-print on Feb 7, this paper initially estimated R0 to be somewhere between 4.7 and 6.6. People dismissed it as being not possible. It was never picked up by the MSM. Now we're seeing from the both the real world and other studies that it's pretty plausible.
- jkhdigital 7y ago
  Yep, I read the preprint as soon as it was published and it scared me into buying masks back in mid-February.
  - snapetom 7y ago
    Basic math, knowing population density, and then that paper was my "oh shit" moment. Got some half respirators and 300 rolls of toilet paper over the next week. The toilet paper wasn't to prepare for a post-apocalyptic world. It was because I knew that was the first thing other idiots would buy when news of this thing hit your average Joe :)
    - DoofusOfDeath 7y ago
      Perhaps I'm misunderstanding your point, but it sounds like your bragging about being the first person to start hoarding.
- squidproquo 7y ago

Animats 7y ago

Stanford just tested 3200 people in Silicon Valley for antibodies at a drive-through location.[1] There are similar group tests being run in LA and Colorado. In a few days there should be more solid info on how many people have had the disease without symptoms. [1] https://www.stanforddaily.com/2020/04/04/stanford-researchers-test-3200-people-for-covid-19-antibodies/ https://www.stanforddaily.com/2020/04/04/stanford-researcher...

droidist2 7y ago
Seems promising! I really hope it's a couple days though and not weeks like the usual coronavirus testing I've been hearing about.
- girvo 7y ago
  The tests here in Queensland give results in 24 hours, according to a friend who was just tested
  - droidist2 7y ago
    That's not bad. In the US my friend just got tested and they said 5-10 business days.
- deelowe 7y ago
  IIRC, the researchers stated yesterday not to expect any surprises based on what they've found so far... :(
- maxerickson 7y ago
  The test takes 10 minutes: https://premierbiotech.com/innovation/covid-19/ https://premierbiotech.com/innovation/covid-19/ They're talking about it being a few days before they release the statistics from the testing.
elliekelly 7y ago
(As someone who knows next to nothing about medicine or microbiology) I’m curious how they already know which antibodies to look for? Are antibodies unique to each virus? Is it possible that some people have stumbled upon antibody X at some point in their lives that maybe isn’t perfect for fighting off this new coronavirus but still helps? Along the same lines, is it possible some people have antibodies IgM and IgG from some other illness they’ve encountered in their lives? Or is the presence of those antibodies conclusive evidence that they’ve been infected with COVID-19?

fspeech 7y ago

The actual article that is both readable and informative https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article

mrtweetyhack 7y ago

According to WHO and China, there is no Covid-19

thisrod 7y ago

This seems a bit odd. If it was my job to estimate R₀ for the coronavirus, I'd look at Singapore, Korea, Australia, New Zealand and so on, where there are thousands of patients, and almost all of them know when they caught it and who they caught it from. Why would you choose to study a place where people don't know those things?

fspeech 7y ago
Because that is the definition of R0. Once people are aware and change their behavior R changes as well and is not readily translatable to a different setting.
- foogazi 7y ago
  So you want to measure transmission rates under normal interactions, not during shelter in place/everyone wearing masks?
  - eneveu 7y ago
    Yes. From the article: Dr Feigl-Ding explains that R0 is the “R reproductive number at time 0 before countermeasures”. He points out that this is not the R(effective) at current time under mitigation measures such as distancing and testing, tracing and quarantine, which are expected to slash chains of transmission.
deleted 7y ago
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ggm 7y ago

I will repeat a question I would love an epidemiologist to reply to: Where is the random background testing? Not testing "I feel unwell" presentations at random, truly going into the field and testing the wider population at random, healthy (believed) or not? You cannot model the IFR accurately from skewed samples and it feels like we aren't even doing skewed sampling.

nitrobeast 7y ago
I believe Wuhan government eventually went door-to-door to test the population exhaustively.
starpilot 7y ago
It's in South Korea where there is an abundance of tests. Where tests or people to administrate them are scarce, we have to prioritize those with symptoms.
- sooheon 7y ago
  There is an argument to me made for the exact opposite. Those who are already sick will be treated according to their symptoms, a diagnosis has little bearing on the treatment they will receive and therefore low value. Meanwhile, proper random sampling of the population will give more accurate prevalence numbers and trends, allowing for much better epidemic response. South Korea (and Singapore and HK etc.) had a specific policy of contact tracing instead of random sampling, which works if you start it early enough and can actually keep ahead of suspected contact spread.
  - Skunkleton 7y ago
    Sick people should be tested when they require medical intervention as it guides their care. It would be a shame to assume COVID when it might be something treatable.
    - sooheon 7y ago
      I'm sure the decision tree is complex, and there are branches where what you say is absolutely true. However, given the testing kit bottleneck, if identification of "something treatable" is crucial, it might be better to test for those treatable diseases that are likely given presenting symptoms. In the extreme case, if you require a ventilator right now or you'll die, nobody needs to wait on verification of the specific viral cause to begin treatment.

deleted 7y ago

[deleted]

yters 7y ago

Twice as contagious = half as deadly?

DesiLurker 7y ago
depends on the death lag, if you are in the exponential growth stage of the outbreak that it.
guscost 7y ago
Much, much less than half. Contagiousness affects the exponential spread.
- yters 7y ago
  So maybe cov2 is on level with the flu after all.
  - guscost 7y ago
    I’m not a doctor, but I’d bet it’s closer to a cold - it spreads much faster, but may be less lethal. Also, when a virus jumps between species, its virulence can be elevated during the initial period of spread. So it might be a “really bad” cold, at least early on: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4361674/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4361674/
    - yters 7y ago
      I wonder why such panic then.
      - guscost 7y ago
        If it's really not that bad, I would guess that the panic is because this is the first time we've been able to observe a brand-new cold virus as it spreads around the world. When the general public starts to understand all of the damage that these things do, and how quickly they can spread, it's understandably pretty scary. Plus a whole bunch of other factors.

bwandu 7y ago

thinkpol doesn't appear to be a reliable canadian media outlet r/fuckthinkpol for stickied thread shows what type of people are behind it

mmmrtl 7y ago

Title correction: this isn't a CDC study, just published in a CDC journal

Scipio_Afri 7y ago
I think they're pretty reputable, regardless. "Author affiliations: Los Alamos National Laboratory, Los Alamos, New Mexico, USA"
Scipio_Afri 7y ago
Also the Bios of a couple of the authors at the end: "Dr. Sanche is a postdoctoral research associate at Los Alamos National Laboratory, Los Alamos, New Mexico, USA. His primary research interest lies in complex disease dynamics inferred from data science and mathematical modeling. Dr. Lin is also a postdoctoral research associate at Los Alamos National Laboratory. His primary research interest lies in applied stochastic processes, biological physics, statistical inference, and computational system biology."

Medicalidiot 7y ago

Here's the study from the Diamond Princess which elucidates what the percentage of the population is asymptomatic: https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2020.25.10.2000180 https://www.eurosurveillance.org/content/10.2807/1560-7917.E...

w3mmpp 7y ago

So, let me get this straight, we stopped the world economy because of mitigation actions based on a R0 of 2 and, it ends up, the R0 is almost 6 which make those same mitigations actions completely inadequate? Well, if I was one of those scientists I'll start looking for another career right now, one that doesn't have anything to do with numbers, because it's the blunder of the century right there. Edit: the blunder I'm talking here is by the scientists that have been telling us R was between 2 to 3 for months.

analog31 7y ago
Anecdote: At my workplace, the people who were the most concerned about the adequacy of mitigation actions were the scientists. We stopped the world economy based on scientists begging for strong measures, and getting weak measures instead.
- w3mmpp 7y ago
  Do you call what we have now weak measure? The whole economy is shut, what more do you want?
  - deegles 7y ago
    In Wuhan they were welding apartment building doors shut, and the government was delivering food. There were drones flying around telling people to go home. There are videos of people being forcefully dragged home. None of the current "it's ok to go out and exercise and buy groceries," which is what is currently happening in NYC. So yeah there are further measures available.
    - w3mmpp 7y ago
      Whole generations of people have been killed for freedom and you're ready to give it all back for a 1% fatality rate? It's a bad bargain imo.
      - fragsworth 7y ago

AzzieElbab 7y ago

If that is true China cases will sky rocket again this month.

cryptonector 7y ago

Excellent. The faster it moves through, the sooner we'll get back to work.

tunesmith 7y ago
You've got to do the math on that. Estimate the percentage of people that have caught it. Then compare that to how 82% people need to catch it in order to have the bare minimum of herd immunity. And factor in that health systems in many regions are already overwhelmed. If you want to get to herd immunity just from catching it, you'd have a health disaster that is impossible to imagine even now.
- aaron695 7y ago
  I suspect in 2 years time the death toll will be about the same for everyone. What we will look at is how countries handled society while it happened. This 'overwhelmed' the system is a deadly meme, the numbers don't work out. The best model might be wear masks, physical distance, keep hands clean, testing and tracing. Ban really large events.
  - tunesmith 7y ago
    I don't see how you can say the numbers don't work out, unless you believe hospital systems are lying when they say they run out of beds/equipment.
    - aaron695 7y ago
      Try to work out the actual numbers for strict lockdown vs not strict and model it over two years being practical. No hand waving. Include the second and third waves for instance. You won't see the difference you think. Vaccines may never happen ( but post a second winter is a best case ) and treatments don't make things much better. Once you get 1000000 dead vs 1050000 two years later we can talk about the additional dead from being unable to do things like cancer surgery.

tjansen 7y ago

There are plenty of anecdotal stories that show that it spreads very quickly. A highly publicized story in Germany was about one of the first ten cases here. This guy merely sat behind a patient and got asked for a salt shaker. That was his only contact. And I know of a company where someone who returned from a vacation in Italy was in a meeting with 6 people. 5 of them got infected.

anovikov 7y ago

No one thought that it depends on people's habits, say common social norms? Say in Asia it was commonplace to wear masks even before epidemic and it is considered polite to stand far away from one another, and people bow instead of shaking hands. Quite clearly there, or say in Sweden with their tradition of having a large privacy distance, R0 is much lower than in Italy where people hug and kiss seeing each other.

LatteLazy 7y ago

If people weren't dying, it would be hilarious had badly understood this epidemic is. Months since the start, we have no idea how infectious the virus is, how many people have been infected, how deadly it is, how effective (or not) containment is, how many people will need to be hospitalised or how long for. It's actually incredible. I'm very cynical, but I wouldn't have believed Western governments could have floundered so badly if I'd been told even a month ago...

tbihl 7y ago
It doesn't help that they leaned heavily on Chinese numbers. Even with data from southern Europe that is likely to be more accurate, people relied on numbers coming out of China because they were early and more numerous... But not enough thought given to openness, and now we've been trying to correct interpolations and extrapolations with a fraudulent starting point for the past two months.
- LatteLazy 7y ago
  China causing this should be a massive scandal. China lying about their numbers so we can't deal with it effectively should be second bigger scandal. Historically, I've been quite pro China (until they started rounding up Muslims recently at least). But this is totally unacceptable. </rant>...
majewsky 7y ago
Do you have any counterexamples where novel germs or viruses were better understood in a shorter amount or time? From my POV, it just looks like a genuinely hard problem right now.
- LatteLazy 7y ago
  I wouldn't dispute its hard. I don't think coronavirus has any comparative example. Nothing this contagious/disruptive has occurred in modern times. I just find it amazing that we're 6(?) months since the first diagnosis, and we know so so little. Maybe that's life, but maybe if China was honest or the US got its testing together we would not be here?

guscost 7y ago

And now we wait for the other shoe to drop: serosurveys showing that at least one-third of the US population has already caught COVID-19 and recovered.

bbeez 7y ago

I hear a lot about how we may be seriously underestimating the CFR denominator, due to undiagnosed mild cases. Ok I get that. What I don’t hear much about is that the numerator is also probably understated at any point in time for several reasons. First I don’t trust the China data I think it’s understated and that’s the oldest, most mature data we have. Second, in an exponentially growing disease with something like a 6 week course from infection through to mortality/recovery, we will always have diagnosed cases that are 6 weeks, or whatever the true course is, ahead of the final death tally and as the diagnosed cases are rising so rapidly, including those weeks and weeks worth of diagnosed but unresolved cases could add up to a huge amount of error to a simple deaths/cases CFR analysis that would significantly understate what the final CFR will look like. Cohort analysis does not appear to have caught on in the CFR calculation world from what I’ve been reading. Third, I’ve read that there are likely a significant number deaths that are probably attributable to COVID-19 that are not being counted as Covid-19. The death rate in northern Italy over the last month, even when all the COVID-19 attributed deaths are removed, is significantly higher than it has been in similar periods in the past I have read. I believe the same is true in New York City. So if these stories are correct, there are likely more COVID-19 deaths than are being counted. So while it is probably true that the denominator is understated, it seems to me that it’s also very likely true that the numerator is also understated making it very difficult for me to believe any of these estimates are very accurate until both these issues are addressed. Has anyone seen anything that explains some of these issues and calculates a cohort-based death rate, which somehow estimates or adjusts were incorrect, time shifted or under counted Fatality data?