A new study in the Lancet reports on a large scale randomized sero-prevalance study in Spain. Spain had been hit hard by COVID-19 with a quarter million diagnosed cases and approximately 28,000 deaths. We think that for herd immunity to be established, a population needs between two thirds and five sixths to have been infected and recovered with persistent immune capacity built up.
The study did not find that:
Findings
Seroprevalence was 5·0% (95% CI 4·7–5·4) by the point-of-care test and 4·6% (4·3–5·0) by immunoassay, with a specificity–sensitivity range of 3·7% (3·3–4·0; both tests positive) to 6·2% (5·8–6·6; either test positive), with no differences by sex and lower seroprevalence in children younger than 10 years (<3·1% by the point-of-care test). There was substantial geographical variability, with higher prevalence around Madrid (>10%) and lower in coastal areas (<3%)….
Interpretation
The majority of the Spanish population is seronegative to SARS-CoV-2 infection, even in hotspot areas… These results emphasise the need for maintaining public health measures to avoid a new epidemic wave.
This increases the confidence in the results out of New York City and other regions that had overwhelmed hospital systems and unconstrained spread: herd immunity in the worst hit areas is not even in vague reach. Lightly hit regions are still at least an order of magnitude of recovered individuals away from talking about herd immunity.
The only ways out are either vaccines, pervasive aggressive and effective public health measures or immense suffering.
VeniceRiley
If not a vaccine, then an effective and readily available and cheap treatment to keep people out of hospital. I holding hope for such a thing. otherwise, I predict President Dollhands will order vaccines released before the election and prior to trials being finished.
Yutsano
I think that’s the problem in the US: a lot of people are getting infected but there are clusters rather than it being widespread. Enough people can say they don’t know anyone who has it that it’s not a big deal to them. And especially with essential workers and food processing plants getting hit it’s even easier to just say it’s a disease for “those people” and act like most folks are immune. All we need to do is mask, social distance, and stay home as much as possible. We do that together as a country we might just have a chance.
Another Scott
Larry Brilliant – “If 80% of people wore a mask 80% of the time, COVID would go away.”
That’s the way out.
That also means, no indoor restaurant seating, no bars, etc. People can’t eat indoors in public and wear masks. Such businesses need federal funding to get over this hump.
We know what we need to do. Will we start doing it??
Cheers,
Scott.
Luciamia
I gotta say, I kinda fell in love with Gov. Cuomo today.
Chief Oshkosh
@Luciamia: Sort of icky, but please elaborate. We all need some good news.
Brachiator
@Another Scott:
If only it were that easy.
Ohio Mom
So immense suffering it is…
I can’t see a chance of public health measures being undertaken seriously until next spring (assumes we hit a trifecta in November).
cain
I never understood this herd immunity – in a large enough population – people are constantly changing – aging or developing health issues – I don’t see how as months progress that new people don’t get added to the danger zone and still help spread it.
WaterGirl
@Brachiator: I’d like to see us get there, and then we can figure out what else we need to do.
Another Scott
@Brachiator: How do we know it isn’t that easy?
He helped eradicate small pox. He knows what he’s talking about.
We know that masks work. We need to be using masks as best we can while the industry works on better treatments, vaccines, testing, etc., etc.
Cheers,
Scott.
Another Scott
@cain: The idea is that the bug cannot move to a new person and infect them if enough of the population is immune, so the virus dies out.
This assumes, of course, that immunity is long-enough lasting for this to happen…
Cheers,
Scott.
Tenar Arha
@Luciamia: Don’t.
I was also enticed by his competence in the face of disaster. I’ve had to remind myself that’s because he’s been digging his state out of the hole he & diBlasio dug them all into by not shutting things down as soon as the first big cluster was identified. (IMHO Much like Charlie Baker failed here initially with the Biogen Idec cluster). I do give both [him & my Governor] credit for finally acting & being cautious now, but I’m not going to pretend that either of them didn’t screw up at first. They look good only because the Feds & now other states’ governors look so much worse.
And honestly, he’s an a-hole. He until recently had engineered the NY legislature to be GOP bc it made it easier for him to control. And he’s done other bad stuff, like starved the subway system of the funds it needs to modernize, or just recently helping to kill that NY bail reform law.
ETA clarity
Steeplejack
“Right. Immense suffering it is, then!”
Yutsano
@Another Scott: We won’t get herd immunity without a vaccine. There is just no way we can get through this with nearly everyone getting infected because of the consequences of infection. That would guarantee a lot more people will die and even more will have lingering health issues. And with ACA possibly facing its death (I don’t trust Roberts any further than I can throw him) there will be a huge consequence should that happen.
Brachiator
@Another Scott:
Using masks?
Early on, he seemed to be against the idea of a lockdown.
And leaned in favor of masks:
His biases continue, but he also rightly notes the importance of testing. He is one voice, and should be listened to. But he is not necessarily the best or final word.
PsiFighter37
@Tenar Arha: I don’t think any of us here are anything but clear-eyed about Cuomo. But once things hit the fan, he has been much better about this. And frankly, all the other crap, policy-wise, can wait until we can figure out a way to deal with COVID-19 more sustainably. Getting back to ‘normal’ and figuring out how to move forward on a lot of other policy issues isn’t going to register unless it’s related to the pandemic.
Frankly, Cuomo is governor for life if he wants after this. Nobody of prominence will ever challenge him, and if the best that can be thrown at him in primary challenges are left-wing gadflies and celebrities…good luck.
Another Scott
@Brachiator: His comments are and have been more nuanced than you imply.
Cheers,
Scott.
Brachiator
@WaterGirl:
I am definitely pro-mask. I just am extremely skeptical when people attach wild predictions of effectiveness to any particular strategy.
Searcher
@cain: They do, both in small outbreaks and over larger regions.
Small outbreaks are easy to see; you have one town or neighborhood where a lot of people aren’t immune, and you get an outbreak.
For larger regions, basically, really bad, uncontained outbreaks tend to overshoot herd immunity by some margin — if “herd immunity” is at 50% for a particular disease, it won’t actually stop at exactly 50%, because when the last 10 or 20 or 30% of people are infected, they’re still running around contagious infecting other people. So by the time the outbreak burns out, 60% or 70% of the population has been exposed.
Over the next 20 or 30 years, the percent of the population immune will continue to decrease as new people are born or move in and people die. Once the immune population drops below 50%, it’s then at risk for another outbreak — if it happens at 48%, it will probably be a small outbreak, and only overshoot back to 51%, 52%. If it happens at 30, 40% it will probably be another bad outbreak, overshooting back up to 60% or so, and another generation will pass before another bad outbreak.
eclare
@cain: Science is still out as to whether or not you are immune if you get the disease. That still needs to be determined. And if you do have immunity, how long does it last?
Luciamia
@Chief Oshkosh: Today’s news briefing. Pretty much tore Trump a new one.
Brachiator
@Another Scott:
I quoted him in more detail than you did.
Clearly, the guy knows his shit. But your quote falsely suggests a single magic bullet to deal with the pandemic.
If the full scope of his recommendations are included in any strategy for dealing with the pandemic, we will all be better for it.
Matt McIrvin
@Searcher: If immunity holds long-term, then the end state for uncontrolled COVID after many of us olds die of it could be that this is a thing nearly everyone gets in young adulthood (with relatively low damage), then they’re clear. But I’m skeptical that it does hold long-term.
scav
@cain: Herd immunity isn’t that no one ever gets it or that everyone is immune. It’s just a very very very flat curve with, at best, small and localized flareups. The virus hasn’t been eliminated from the planet. The population is just at a point where the odd are that an infected person will most likely interact with someone who’s had the disease or are otherwise immune to it — the virus in effect has to work harder to find someone to infect. Only it’s people’s immune systems doing it rather than physical means like masks, shields, washing and distancing.
WaterGirl
@Brachiator: Let’s not knock it til we’ve tried it.
wvng
Here in West Virginia it seems the tent revival circuit has ramped up. Five days in one place, pack em into a tent, lots of shouting and praising and singing and shared food to get them to come and no masks, and then off to the next town. Just happened here in my county. Seems like “immense suffering” is in the cards here.
Another Scott
@Brachiator: His 80% comment was deliberately provocative. You know that. That’s not the sum-total of his comments on it.
buckinstitute.org/covid-webinar-series-transcript-of-session-with-larry-brilliant-md-mph/ (from April).
(Emphasis added.)
He knows what he’s talking about.
There are many other discussions like that, like the Franken podcast.
Your tut-tutting and saying, oh it’s so much more complicated than that, doesn’t seem too productive to me.
Cheers,
Scott.
VOR
@WaterGirl: Mask wearing has worked in places like Hong Kong, which certainly qualifies as a dense urban environment.
I think one of the early problems with messaging was masks = N95 or better, medical grade. Use of consumer grade masks came later. N95 and medical grade masks were in short supply early in the pandemic, a problem which may or may not be solved. The consumer grade masks are much less than perfect and would not be acceptable in a hospital setting. But an 80% solution may be good enough to take the edge off transmission and stop widespread outbreaks.
MisterForkbeard
@wvng: I was saying yesterday that my county is CA (while pretty good for CA) is still in per-capita worse shape than WV.
But we don’t have stressors and events like this.
Brachiator
@WaterGirl:
I live in California. I have reasonably high confidence in the recommendations of the governor and the Los Angeles County health officials. And this includes their recommendations concerning masks.
If Brilliant’s detailed recommendations fit in with a larger strategy, then I will pay attention to that.
As I noted, even the “80% or the people 80% of the time,” does not mean much without an effective testing regime and other actions. And this is from Brilliant himself.
Wanderer
Well it seems the Superspreader Carnival of Hate will be arriving in N.H. for a meeting Saturday. N.H. has been doing ok numbers wise recently. Not looking forward to this event happening.
wvng
@MisterForkbeard: that you know of. I had NO IDEA that revivals were happening, until there it was in our town. The local churches have mostly been being careful, and I thought that was the extent of the religious threat.
artem1s
our basic inability to grasp the numbers is why we keep floating this idea of herd immunity around. Bubonic plague swept thru England every ten years for a century, killing 10% of the population each time. Exactly when did they achieve herd immunity? We have 7B people on the planet – 3.5B would have to become infected (assuming 50% would give you herd immunity) = 350M dead before you get there (assuming 1% death toll).
US 350M – 175M infected = 1.75M dead if we are lucky. And who knows how many waves we have to got thru to get to 50% infected. Could take years or decades. In the meantime with every wave, our ability to ‘live with it’ diminishes exponentially. We have probably already seen the deaths of 100s of researchers who might have had the expertise to work on a vaccine. How many waves until we descend into a global economic collapse? another dark age?
cain
That won’t work in dense urban areas. There is just too much variables there and as I said the longer it goes on – all new targets will be created.
cain
My brother told me that he knew someone who got the disease twice. That’s not encouraging.
cain
@scav:
Sure I get that. But you need to start that at the end of the curve not at the beginning. Otherwise you need to use mitigating devices like masks. Otherwise you’re just not going to get herd immunity.
Some countries could do it, but so far every experiment regarding herd immunity has not gone down well.
Brachiator
@Another Scott:
The short bit that you originally posted, without any supporting link or context, was provocative and insufficient.
You are usually better than that.
We agree on the essentials, including the use of masks.
Ultimately, you are fighting with yourself, not with me.
Martin
@Another Scott: Sort of.
The hard part about wrapping your head around this is we think of the mask as an individual step to protect the individual, but that’s not really the concern of epidemiologists exactly.
The R effective is both function of the disease as well as the population. The 80% masks/80% of the time would work, if people kept wearing masks even when there were only a few dozen cases in the country. The population won’t do that. Sure, at 50k new cases per day we will, but once it gets rare we won’t, which is why we don’t now wear masks to protect from measles, a much more contagious and deadly disease that is 100x more common than it was a decade ago.
The 80/80 advice is great advice to get Reff down, get case numbers down to Europes levels, to where the 20% of people not wearing masks and the 20% of the time everyone else doesn’t wear masks keeps the disease banging around. As explosive as an exponential function can cause something to grow, it also carries a tail that is extremely hard to zero out, because even as a rare disease, it’ll spread rapidly through families, and flare up.
Once you get to say, where NY is right now, you have to contact trace the fuck out of things, while maintaining other protections. 80/80 doesn’t work. It helps, don’t get me wrong, we should keep doing it, but you really need to start adding a whole bunch of other proactive government stuff to the problem which is right now handled by ‘stay the fuck home’.
Needless to say, we’re nationally a complete dumpster fire at ‘proactive government stuff’.
raven
Charlie Daniels died, AMF.
randy khan
@cain:
The way any virus stops spreading and disappears is that the R value drops below 1 (that is, every person who gets it gives it to less than one other person) and stays there. Herd immunity drops the R value because the number of targets for the virus goes way down – instead of 9 of 10 people, it’s 3 of 10 (give or take). It doesn’t have to be in place forever, just long enough for the virus to more or less die out for lack of current hosts.
And there are lots of examples of viruses that die out without vaccines or herd immunity – SARS (the original) did, for instance, and that’s typically what happens with outbreaks of Ebola (unfortunately, that’s because it kills its hosts so efficiently, which limits the spread).
artem1s
@Martin:
we’re nationally a complete dumpster fire at ‘proactive government stuff’.
Bingo
raven
@randy khan: Did the Spanish Flu do that?
Another Scott
@Brachiator: I heard the 80%/80% a while ago.
It’s in marinij.com/2020/06/06/marin-epidemiologist-larry-brilliant-virus-crisis-just-beginning/ from June. It’s not clear whether it’s also in this podcast from June – medium.com/@RepHuffman/off-the-cuff-with-dr-larry-brilliant-3ea84fa2b842
FWIW.
Cheers,
Scott.
scav
@cain: The mechanical means are more like a crutch, helping us to limp in a semi-controlled manner toward — we hope — herd immunity. But maybe I’m just not getting exactly what mechanism you’re wrestling with.
Barbara
There are some diseases where long term immunity does not take hold if your case is too mild. One of my kids had chicken pox when she was six months old and my pediatrician told me that babies often have cases that are so mild they are still at risk of getting it later. Hers seemed to be bad enough to confer immunity. But the low level of seroprevalence of COVID-19 could be explained by factors other than lack of exposure.
MisterForkbeard
@wvng: That’s a good point.
My county has roughly the population of Wyoming and Vermont and the same overall amount of cases, though I don’t have any information on current case count. We’re at about 600 total with somewhere between 40-80 per day.
The problem we’re having now is… tourism. Evidently the city tourism board has been trying to get people to come out here, including things like touring our downtown or going to the wineries in the area in groups. No large events, but the people and vendors I know think the whole thing is crazy.
But then, we’ve already had influxes of people here from fucking Florida of all places, because they decided it would be fun to vacation in Wine Country.
Fair Economist
@Matt McIrvin: The rule for flu is that exposure even in childhood to a related virus provides substantial protection even in advanced old age. In the 1968 H3N2 flu pandemic, people over 88 had a much lower chance of dying, apparently because an H3N2 flu circulated prior to the 1889 respiratory pandemic. We also know people from isolated communities are very prone to die when exposed to common respiratory pathogens, so at least some of our “common cold” viruses are pretty dangerous if immunity isn’t developed early. It’s reasonable to try to confirm immunity will be similar for SARS-COV2 but policy actions should assume it works like almost every other known virus.
Another Scott
@randy khan: +1
Reff and Herd Immunity are intimately linked by the math. Reff is a function of measures that we put in place to stop transmission and infection. If 80%/80% drops Reff low enough, for long enough, then the virus will die out. If our mitigation measures only flatten the curve, the the virus will be with us until there is a vaccine. My take is that Brilliant is arguing that 80%/80% will definitely help with the latter – it will “go away” as a public health concern (even if it isn’t totally eradicated).
Everything I’ve seen from him (e.g. the Franken podcast) indicates that he thinks it may be 5 years before an effective vaccine is created and distributed to everyone on the planet.
FWIW.
Cheers,
Scott.
Martin
@cain: Epidemiologists model this most simply using a SIR model which breaks the population down into 3 groups:
If a new disease breaks out, you have a handful of people in the I category, nobody in the R category, and everyone else (basically everyone) in the S category. Any time an I comes in contact with a S, there’s a chance the S gets infected and becomes an I. In this simplified model, if someone recovers and has immunity, or if they die, they move to R (there are more advanced models that treat deaths and recoveries differently, for when you get limited immunity, or for when you are trying to model fatalities).
But in the model, every time an I interacts with an R, there’s no risk of infection. So as people steadily move from the S category to the R category, each interaction by an I has a lower chance of being with an S (unless it’s 100% fatal) and a higher chance of being with an R, and so the odds of the disease finding an S to convert to an I goes down. This is generally a VERY slow process, but over time the disease becomes harder to spread. The key here is that an I is only in the I category for a limited period of time before they move to the R category. If you can reduce the odds of an I conversing an S to I to a low enough level that they create new I slower than they transition to R, then the disease starts to die out.
Herd immunity is when so many people get moved to R that the odds of an I coming in contact with an S are extraordinarily low.
Vaccines move people from S to R without having to go through I.
There are a few other considerations in here. For some diseases that give limited immunity, you need to move people from R back to S after some period of time (usually months-years). In those cases, you may never achieve herd immunity. The flu is such a category of diseases. The best you can hope for is to attenuate the problem so you don’t get mass outbreaks, and to protect at-risk individuals.
For very slow moving diseases, it’s possible you get population replacement faster than the disease moves. That is, people move from S to R due to car crashes and cancer and shit faster than they do through the disease, and you end up replenishing S all the time just through lots of babies. I can’t think of such a thing offhand, but I’m sure there are examples.
One way to think of it is you’re standing in a ballroom at the national Dave convention and your goal is to ‘never interact with someone named Dave’. Gonna be pretty tough. but if you steadily remove the Daves from the room and replace them with Joes, at some point you’ll have a ratio of Joes to Daves which is high enough that you will struggle to find the Daves in the room, even if there’s still a few there. You can then flip the challenge to ‘you must interact with someone named Dave’ and it’ll be nearly as hard as the original challenge. If you’re timed (how long you are infectious) at some point it will become so hard to find a Dave in that limited period of time that you effectively can never do it.
That’s herd immunity. The ability to hide a few Daves in a sea of Joes
I will add, herd immunity is a goal. There are always people who can’t be vaccinated, so the way you protect them is to vaccinate everyone else so that the disease has such a hard time finding the unvaccinated people that it basically can’t. Antivaxxers threaten the lives of these people by demanding they be included in that group, for no good reason other than their own selfishness.
Martin
@Barbara: And one reason why measles is so important to eradicate is that it resets the immunity of most other diseases. Get measles and you’re probably no longer immune to any of the things you got vaccinated for or had caught before. You have to get revaccinated for everything, which is why the measles antivaxxers are so dangerous.
Fair Economist
@randy khan: I wouldn’t consider SARS or Ebola as examples of viruses that “die out” Both were eliminated only by *extremely* aggressive public health measures.
All the 20th century flu pandemics continued to circulate until the next pandemic replaced them, except H3N2 from 1968, which continues to circulate in spite of 2 subsequent H1N1 pandemics (although it looks like SARS2 will finally do it in: there’s been only 1 verified case in the US in the last 2 months).
Coronavirus OC43 has been circulating in humans since at least the late 19th century. SARS2 is very unlikely to go away on its own for decades at least, although after most people have had it, it will probably be less lethal.
scav
@Martin: For the ‘slow moving diseases’ example, there might be some flu variant examples that basically fit. There seem to be generational differences in exposure for both the Spanish flu and the @Fair Economist: case.
Gravenstone
@VeniceRiley: He can “order” anything he wants. Logistically there isn’t a snowball’s chance in Hell of having a viable quantity of any vaccine by November. Closest chance is companies making existing vaccines that might prove effective on an “at risk” basis just to start stockpiling in case of a positive testing outcome.
Martin
@Fair Economist: Almost no disease dies out on its own. Pareto principle applies here. Outbreaks are somewhat self-attenuating – at some point people fear for their own well-being that they take the steps necessary to slow the spread. Historically, that was harder because we didn’t have the scientific knowledge and ability to communicate to inform the public, but now we do.
So, it’s harder to have a bubonic plague-like event now. It really just can’t happen without a very unusual type of disease, which is increasingly unlikely to come about.
But at the other end, diseases are as hard or harder to wipe out as they used to be mostly due to increased mobility. All that knowledge doesn’t really help when the thing you need to do is to contain everybody. That last few percent is incredibly hard to solve. We’ve had a measles vaccine for over 60 years, and we still haven’t wiped it out even in the US, even with all of our checkpoints for vaccinations among children, having it be mandatory to attend school for so many, and so on. We still have some new polio cases showing up in the US from people that bring it in from out of the country.
Gravenstone
Oh sweet Jesus, friend just told me that their boss’ family (but not him, so far – getting retested) all tested positive for covid-19 after returning from a cross country camping expedition. His employees are in people’s homes on a regular basis through their work. This could get ugly.
Martin
@Gravenstone: Yep. Coming up with the vaccine is only part of the problem. Making 300 million of anything is a whole different category of problem.
What’s more, 40% of Republicans say they won’t get the vaccine when it becomes available. We’ll see what actually happens, but the noncompliance rate alone is high enough to prevent herd immunity.
And if the vaccine is released before tested, that rate will go up, and when that testing shows that it’s safe, it will be too late. Trust broken. We’ve had vaccines fail before. HPV got so politicized that it effectively failed. Who knows what’s going to happen here.
Carlo
@Martin:
To Martin’s excellent SIR primer, I’ll add a less widely-known fact that is worth emphasis: In the absence of a vaccine, achieving herd immunity does not mark the end of the epidemic!
Herd immunity is the moment when the epidemic is doomed, since recoveries and fatalities now outpace new infections, so that the number of infected individuals declines. However new infections are not 0 at HI, and the epidemic keeps on rolling for quite a while before they disappear.
As an example, for a R0 of 3 (some estimate this as the R0 for COVID-19) HI occurs at 1/3 of the population getting the virus, but by the time the new infection rate goes to zero (the formal end of the epidemic) about 95% of the population has been infected by the virus. Basically, everyone sees it.
There are some lower bounds to the infection fatality rate (IFR) of about 1/1000. That’s the chance of dying of COVID-19 given an infection, accounting for the fact that many infected individuals are asymptomatic, and don’t get tested. This would mean that if we in the US tried for HI without a vaccine, we could expect more than 300,000,000 infections and more than 300,000 fatalities.
That’s why “just get it and get it over with” is a stupid national response. The Swedes are nuts. That’s not a model anyone should try to copy. Until we have a vaccine, or at least some decent therapies that reduce fatality and infectivity, we need masks and distance. If we could get the case rate down, testing and contact tracing programs work at nation scale. “Go for HI” is not a sane alternative.
ColoradoGuy
Well, if Republicans don’t get the vaccine and Democrats do, that’ll be a large-scale experiment in Darwinian selection.
Tenar Arha
@PsiFighter37:
Yep. I do get it, and New York may do as it likes. I just won’t accept the underlying assumption that basic governing competence alone is all I can expect during an emergency. Because if I did, I’d be stuck with my blandly technocratic status quo GOP Governor Charlie Baker for the rest of my life, even though our Governors, here in MA, at least have less power. I’d prefer a Democrat. ?
WaterGirl
@Gravenstone: Who the hell goes cross country camping during a pandemic???
Glidwrith
@WaterGirl: That would be the description of one of my co-workers. Damn fool and two others won’t mask at work or social distance. I’ve had to put up signs and shut my office door and they just yell THROUGH the door instead of masking.