As late as 1980, Polio was crippling 300,000 children every year. It's now down to a few hundred, at a bargain price of order $10B (total, not per year). It's natural to wonder whether it makes sense to push to fully eradicate the disease (which will cost billions more) rather than simply controlling it (presumably at a substantially lower cost) for a few decades until the regions become wealthy enough that eradication is cheap (at least relative to the local economy). This is not at all an obvious question; for organizations that are somewhat economically rational like the Gates Foundation, billions spend on eradication is billions not spent on other developing world interventions that might save more lives.
It is obvious in my mind. Vigilance is the only reason it's so close to eradication. Not completing the eradication risks enormous consequences. Not if, but when. The cost of eradication is thought to be in the billions of dollars. A pittance compared other government spending around the world.
I say just get it done so we dont have to deal with it any more. Unfortunately the plan seems to have some problems.
The other answer has covered resurgence from natural reservoirs.
I'll cover man-made resurgence. There are copies of it in all major countries' virology labs. Furthermore, it can be synthetised from scratch since 2002, see NYT.
Once it's gone, it's gone for good. It can cross the species barrier between us and monkeys, but monkeys have never been found to be natural hosts of the virus.
I have a friend who was one of the last few cases in the 60's to get polio. It's something that I wouldn't wish on anyone.
So the downside of not spending the effort to eradicate it is that someone's child will get it. I'd hate to think that some Billionaire like Larry Ellison would get to pick another mega yacht, rather than doing this.
You're thinking about it the wrong way. Why spend $X saving ten polio children and not the same amount to save a hundred dengue fever (or whatnot) children? At some point, you get diminishing returns, and the amount of lives saved per dollar drops below some other cure's.
Because diseases aren’t some static thing that we can keep in a definite state of low infection forever. Letting it exist allows it to evolve. Ten polio children today could easily become ten thousand polio children tomorrow.
We know we can eliminate it, which is more than we can say for most diseases. Pumping cash into other disease treatments doesn’t have that same guarantee.
> Letting it exist allows it to evolve. Ten polio children today could easily become ten thousand polio children tomorrow.
I know nothing about polio, but is this demonstrably true, is polio seen to be mutating, and it is considered a real risk by scientists that a strain could emerge that is invulnerable to vaccines?
Polio can definitely mutate to forms resistant to the vaccine. An outbreak in the Congo in 2010 resulted in 450 infections with a nearly 50% mortality rate. When scientists tested the strain on samples, they estimated that ~20+% of the population would still be susceptible in a fully vaccinated group. Not good..
This is the key. We have limited resources, so any decision is always a trade-off. If you do X it means you can’t do Y.
A big killer of children is diarrhea. 800,000 die each year and treating it cheap and preventing it is just access to clean water. You can get a huge bang for your buck by spending money on it.
> Even digging a well (as opposed to surface water) is very possible for not a lot of money.
> And as a result, an entire community can have access to clean water.
Well, no. All communities have water sources. Where digging a well is cheap, the community will have one or more.
The problem digging a well solves is that there wasn't enough water. That's not the problem a community with endemic diarrhea has. Their problem is that they're not keeping their water clean. The new well is unlikely to be different.
Ellison will buy another yacht regardless of polio eradication status. He'll either want the yacht or want to be charitable. And if polio is gone, he can fight malaria, dengue,etc.
They're having trouble even controlling these type-2 outbreaks. The fear is that attempts to do so by deploying live type-2 vaccine in the surrounding areas may instead be triggering a positive feedback loop, with more rather than fewer infections over time. This would be a clearly misguided response, even before you account for opportunity costs - which is not easy, because letting things be and hoping that the outbreaks will die out on their own has costs as well.
Yea, but if controlling it allows a mutation that makes it more difficult to control it could cost significantly more; plus you get to say you eradicated polio without having to take R/D risk.
The problem with simply controlling it is that you're asking real people to give their children a vaccine that has a non-zero chance of actually giving them polio. When the disease is already well controlled, who would want to do that? And how would those who do feel if their child does get the disease from the vaccine? There are good non-economic reasons to push for eradication.
There's an injectable vaccine that doesn't contribute to reactivated polio. Also, the oral vaccine doesn't "give" polio to the recipient. The person stays immunized, but then in rare cases may be spreading reactivated polio to third-parties.
So it seems like the injectable vaccine will be strictly preferable if the nOPV strategy fails. It's only disadvantage is that it does not prevent the recipient from spreading polio to others if they become infected, and it looks like that disadvantage may have been illusory anyway.
No, both the vaccine receipient and third parties are at risk of getting a full-on paralytic polio infection from the oral polio vaccine. When this happens to the recepient it's called vaccine-associated paralytic polio. See for instance https://www.cdc.gov/vaccines/vpd/polio/hcp/vaccine-derived-p...
It's also worth paying attention to the precise distinction between vaccine-derived poliovirus, which is the problem this article was about, and VAPP. VDPD is basically equivalent to normal wild-type poliovirus in terms of its infectivity and effects, but only happens once the vaccine poliovirus has been circulating and mutating for a while and can be protected against via vaccination. VAPP is caused by vaccination and can affect the recipients or those around them, but unlike VDPD the people who suffer from it shouldn't pose any more danger to others than any other vaccine receipient.
> No, both the vaccine receipient and third parties are at risk of getting a full-on paralytic polio infection from the oral polio vaccine.
That seems like it would make the oral vaccine even worse, compared to the injected vaccine. Again, I'm not sure why they think reintroducing traditional type-2 OPV is a good idea if the injected form that won't cause vaccine-derived outbreaks is so easily available. (Of course nOPV is expected to be better than the former OPV, but it's yet to be available.)
Part of the problem is that there wasn't enough supply of the inactivated vaccine, and arguably there still isn't and probably won't be for some time. See for example https://academic.oup.com/jid/article/220/10/1545/5432103 Also, while the inactivated vaccine protects receipients from the risks associated with polio infection, unlike the oral vaccine it may not be all that effective at preventing it from replicating in their bowel and then infecting others.
I'm not exactly sure why the WHO rushed to pull type 2 from the oral vaccine before there was sufficient supply of the inactivated vaccine to replace it, but I get the impression that they didn't expect it would be necessary because they thought that type 2 virus would rapidly disappear once they did so.
That's not the only disadvantage. The injectable vaccine needs a cold chain, and as with all injectables, involves the proper handling and disposal of sharps. It's also physically larger, which is a larger problem than many people realize - vaccination campaigns are actual real world applications of the knapsack problem.
Sure but if it only has to be used in small-scale campaigns to deal with individual flare-ups of the disease, these look like solvable problems. We're not talking about deploying it country-wide.
The responses are not that small-scale, the guidelines call for vaccinating as many children aged 0-5 as can be done with good coverage, e.g. half a million children within 14 days and 1-2 million within 6 weeks.
The injectable does not prevent transmission it 'only' protects the recipient from paralysis they can become infected and be a carrier. Only the oral vaccine prevents the disease spreading.
You’re assuming a rational world, which we do not live in.
People will believe all sorts of stupidity, and if anything, as poor countries get richer and more communicative, they’ll invent conspiracies and other reasons to avoid vaccination.
Seems your underestimating how much research and infrastructure was required for eradication. This isn't just evil greed money going straight to the pockets of cold CEOs. All those scientists, doctors, lab techs and everyone associated with the manufacture of vaccines/drugs have to eat.
Like $100m that was ~~~spent~~~ wasted on Juicero. I was listening to the scientist working on the UCSF kidney project and he was estimating it would cost around $100m to successfully get his project through FDA testing. And it was a long rocky road for him to get where it is now.
Indeed, which is why you should spend the money judiciously, instead of on something wildly expensive vulnerable to a relatively inexpensive supersonic cruise missile.
That's a great question, and there are very likely a few places we can throw 10B on and completely change the fate of Mankind, but we don't do that because the gains are not excludable.
Governments and charities should be acting in an economically rational manner though.
For instance, if they can spend $1 for $2 of benefit, they should probably do that before they spend $2 for $3 of benefit. This is kind of a slippery point, because they are often engaging in activities where the benefit is hard to measure, but their activities should still appear rational relative to their best measures of the benefits.
An issue now in the (former) tribal areas of Pakistan is that people are using their kids as bargaining chips with the government for other services they feel are due to them
Governments around the world spend almost two trillion dollars a year on militaries. With only a tiny fraction of that you could blanket regions suspected of harboring Polio with para-dropped doctors. So much for the "knapsack" problem mentioned elsewhere in this thread.
But governments around the world care more about shaking big sticks at each other than eradicating polio.
I've read that polio eradication efforts in Pakistan were set back by CIA efforts to find Osama bin Laden, of all things.
Between 2004 and 2012, the number of polio cases in Pakistan closely mirrored the number of drone strikes. But from 2013 onward, polio cases increased while drone strikes fell.
This can be explained by the CIA's use of a fake immunization campaign in a failed attempt to obtain the DNA of Osama bin Laden's relatives prior to his assassination in 2011. This seemingly vindicated militants' suspicions that vaccination programs were a cover for espionage. Militants consequently intensified their disruption of immunization campaigns, resulting in an increase in polio cases in Pakistan, as well as in Afghanistan, Syria, and Iraq.
According to the article, the trivalent vaccine is a live virus and occasionally reverts to a virulent strain. So while the trivalent vaccine can generally stop outbreaks it also paradoxically causes them in a tiny percentage of cases. Using it means you cannot eradicate the virus entirely as the vaccine itself causes new outbreaks.
I wonder if there is any sort of genetic basis to who might get sick from the trivalent in the small percentage of cases. Not that it’s a viable strategy but then you could selectively give those people only the trivalent.
It should reduce the number of flare-ups of type 2, since everyone would be protected again, but you'd also be back to the situation where anyone could be exposed due a vaccine derived case. The goal is to eradicate the disease completely so that the vaccine doesn't need to be used, since it can trigger cases. Going back to the trivalent (ie going back to distributing the type 2 vaccine widely) would be a step back from that goal, albeit maybe a necessary one.
Depressing read. I knew the effort was facing PR challenges in South Asia, but I didn’t realize the tricky problems outside that region stepping down from the old vaccine.
It doesn't exactly seem to be widely advertised, and a lot of the press coverage is misleading. There was some (rather confused) discussion of this problem on HN a month or so ago: https://news.ycombinator.com/item?id=21730795 That article, like others, made the horrendously wrong claim that types 2 and 3 of the poliovirus had been eradicated. They hadn't. The original wild versions had, but vaccine-derived versions of them which were every bit as dangeorus as the originals were in increasingly widespread circulation - the only difference, as far as I know, is that we can use genetic testing to trace their lineage back to the vaccine.
The slightly better publications like Ars Technica qualified this by saying that this only applied to wild-type polio viruses and did mention vaccine-derived polio, but they severely downplayed how much of a problem this was for the campaign to eradicate polio.
> Some experts fervently hope to avoid reintroduction of the trivalent vaccine. “It would be an enormous blow to the polio program and to international public health,” says Nicholas Grassly, a modeler and epidemiologist at Imperial College London
It's sorta disgusting to see someone on the other side of the world considering it to be a PR disaster instead of just doing damage control if you must but do effing go back to the trivalent vaccine known to be effective.
You are misunderstanding. They aren't worried about PR because it will hurt their reputation or bottom line, but because it will hurt their ability to get communities to go along with vaccination efforts that are vital.
For example, think of seat belts... they save a ton of lives, but it is possible for a seat belt to kill someone; let's say the ratio is 1 death caused for every 1000 saved. Even though a seatbelt can kill you, it is still clearly worth it to use one, and will save a ton of lives if everyone uses them.
Now imagine a celebrity is killed by a seatbelt; rationally, everyone should understand that it is a rare event, and that it is still worth it to wear your seatbelt.
However, since the case is such high profile, many people will see it and mistake the anecdote for data and think seatbelts are dangerous.
> The oral polio vaccine contained three types, or strains, of the virus (types one, two and three). The vaccine, given to young children, is dropped onto the tongue, where it then travels through the stomach and digestive system. The live viruses in the vaccine have been weakened, so that it can’t cause disease. However, in very rare cases, and only in populations where immunisation rates are low, the vaccine virus can mutate in the intestines and regain the ability to cause paralysis, resulting in VDPV. The most common of the three vaccine strains causing VDPV has been the type 2 strain.
> Although the person who received the vaccine does not develop polio, the reactivated polio vaccine leaves their body in faeces and can potentially infect others.
> This is not a risk with the injectable polio vaccine, such as the one given in the UK, as the virus has been inactivated and doesn’t enter the gut. However, this vaccine cannot be used alone in places at risk of polio and where immunity is low. Although it protects an individual from paralysis, it does not prevent the virus being transferred from person to person – an important benefit of the oral vaccine
The problem is the effect of the 'bad PR'. The end of the article goes into the struggles involved in distributing the vaccine and making sure it's used. If the program loses credibility, those struggles could increase to the point where it's no longer effective.
Honestly what's surprising to me is that they're able to overcome that resistance at all. Imagine trying to distribute a vaccine in the US that is known to trigger outbreaks of the virus it's supposed to protect against. Regardless of the fact that things would be far worse without it, all the evidence in the world wouldn't be enough to convince many people.
>Honestly what's surprising to me is that they're able to overcome that resistance at all. Imagine trying to distribute a vaccine in the US that is known to trigger outbreaks of the virus it's supposed to protect against. Regardless of the fact that things would be far worse without it, all the evidence in the world wouldn't be enough to convince many people.
Western risk assessment is warped by the fact that a great many people never have to weigh risky decisions because for the most part society is wealthy enough that we can just defer risk of physical harm at the expense of either time or money. Of course people will freak out when they're given a decision where there's a risk of physical harm in both options.
People used it in the past. If your child has a real risk of contracting polio you would do anything to get them that vaccine.
The anti vaccination movement has only survived because most of these diseases are so rare. If we see a return of diseases like polio the anti vaccination movement would disappear fast.
So it's basically like seatbelt use. There are certain types of crashes where a seatbelt could cause more harm than good (such as crashing into a lake, the seatbelt gets stuck, and the victim can't get out). However these are rare enough, that the benefits of seatbelts far outweigh the risk, that most people decide to wear them (including the benefit of not getting a seatbelt violation ticket).
As the article says, the trivalent vaccine is a live, albeit weakened, virus and occasionally reverts to the original virus which means it occasionally causes an outbreak. The whole point of phasing it out is to get rid of polio which you cannot do if the vaccine itself is causing outbreaks.
Here's the economic case for eradication:
http://polioeradication.org/wp-content/uploads/2016/07/Econo...