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Here’s a more interesting dilemma, one which I could hardly believe once I heard it: > More Polio Cases Now Caused by Vaccine Than by Wild Virus If that’s tru

Here’s a more interesting dilemma, one which I could hardly believe once I heard it: > More Polio Cases Now Caused by Vaccine Than by Wild Virus If that’s true, at what point do we stop vaccinating for it? 1. https://www.nytimes.com/aponline/2019/11/25/health/ap-af-med-africa-polio.html https://www.nytimes.com/aponline/2019/11/25/health/ap-af-med... 2. https://www.npr.org/sections/goatsandsoda/2017/06/28/534403083/mutant-strains-of-polio-vaccine-now-cause-more-paralysis-than-wild-polio https://www.npr.org/sections/goatsandsoda/2017/06/28/5344030...

tyingq 7y ago
To be clear, it's the cheap, oral, live virus polio vaccine that's causing the problem. They don't use that in the US, at all, and we don't have the issue. We don't need to stop polio vaccination...we need to find a reasonable way to replace the low budget version.
- EGreg 7y ago
  I don’t know why you are being downvoted, what you said is entirely correct AND cuts through the confusion. People need to realize that there are different Polio vaccines and the original Salk vaccine has zero chance of infecting people with Polio.
  - akamaka 7y ago
    I downvoted because it’s not correct to suggest that OPV is being used because it is a “low budget version”. In fact, both types of vaccines are being given to children in high-risk countries, as part of the transition away from the live vaccine. In countries with endemic polio or where there is a high risk of imported cases, the WHO recommends OPV vaccine at birth followed by a primary series of 3 OPV and at least one IPV doses starting at 6 weeks of age. https://en.m.wikipedia.org/wiki/Polio_vaccine https://en.m.wikipedia.org/wiki/Polio_vaccine
    - tyingq 7y ago
      "The IPV that has been used in the United States since 1987 is as effective as OPV for preventing polio" https://www.cdc.gov/vaccines/vpd/polio/public/index.html https://www.cdc.gov/vaccines/vpd/polio/public/index.html "Unfortunately, IPV costs considerably more than OPV per dose ($3-5 vs $0.12 on the subsidized world market). Because the WHO and most countries have plans to continue vaccination for at least 10 years after eradication, there will continue to be a market for the vaccine. Because of the high cost of the IPV, efforts are underway to derive improved and less expensive IPV vaccines." http://grantome.com/grant/NIH/R44-AI120260-02 http://grantome.com/grant/NIH/R44-AI120260-02 "One hundred twenty-six low- and middle Income countries will start to use IPV, which is injected, in a single dose, in addition to the oral polio vaccine (OPV). OPV will gradually be phased out, based on certain epidemiologic triggers. The previous price was a major barrier to making this shift. The shift is needed because, for eradication to occur, the polio virus needs to be gone from people, labs, sewage, etc. – i.e. the places in which vaccine-derived polio virus can survive, mutate and cause disease. IPV is ‘inactivated’, and does not carry risk of polio infection to people who are not vaccinated." https://blogs.unicef.org/blog/lowest-ever-prices-for-polio-vaccines/ https://blogs.unicef.org/blog/lowest-ever-prices-for-polio-v... The WHO only recommends OPV because of the low cost.
      - akamaka 7y ago
        IPV induces very low levels of immunity in the intestine. As a result, when a person immunized with IPV is infected with wild poliovirus, the virus can still multiply inside the intestines and be shed in the faeces, risking continued circulation. “...as IPV does not stop transmission of the virus, OPV is used wherever a polio outbreak needs to be contained, even in countries which rely exclusively on IPV for their routine immunization programme. Once polio has been eradicated, use of all OPV will need to be stopped to prevent re-establishment of transmission due to VDPVs.” http://polioeradication.org/polio-today/polio-prevention/the-vaccines/ipv/ http://polioeradication.org/polio-today/polio-prevention/the...
    - onetimemanytime 7y ago
      well it is correct: "But the injectable polio vaccine (IPV) is a better way to inoculate children against the disease: it is safer because it does not carry the live virus. Unhappily, it is also more expensive." https://www.economist.com/feast-and-famine/2013/07/19/injecting-competition https://www.economist.com/feast-and-famine/2013/07/19/inject... Still, now that price has dropped to less than $1 per dose, I am sure rich governments or simple rich people can foot the bill.
- akamaka 7y ago
  The live vaccine is not simply a “low budget version”, it’s more effective.
  - tyingq 7y ago
    It is not.
    - Fomite 7y ago
      There's a number of reasons the live polio vaccine is preferred in developing countries. The biggest is that the OPV vaccine, as the name suggests, is oral. You don't need needles, which means it's easier to mass administer, you don't have to deal with sharps, etc. I think people vastly underestimate the logistical difficulties of delivering vaccines, especially injectables that require a cold chain like IPV. It also sheds, which is good if you're struggling with vaccine coverage. Whether this is a downside or not is a highly dynamic question - as we get closer, the side effects become a bigger deal, but part of the reason they're a big deal is because WT polio is so heavily suppressed.
    - milankragujevic 7y ago
      See this link: https://en.wikipedia.org/wiki/Attenuated_vaccine#Advantages https://en.wikipedia.org/wiki/Attenuated_vaccine#Advantages Advantages of an attenuated vaccine: - Activates all phases of the immune system - Provides more durable immunity; boosters are required less frequently [other are mainly logistics] The disadvantage is that it may cause a reversion to virulence in 3 per 1 000 000 doses given. And it cannot be used in immunocompromised individuals.
makomk 7y ago
That's the truly nasty part of this dilemma: we can't stop vaccinating for it. People who haven't been vaccinated are most at risk of being infected due to the polio vaccine, since the vaccine-derived strains spread from person to person just like the wild polio that they almost eliminated and become more dangerous as they do so. In order to keep those infections under control people are being vaccinated on a massive scale, which works in the short term but spreads massive amounts of the vaccine poliovirus which will cause infections further down the line. The injectable polio vaccination might offer a solution since it uses a dead virus that can't cause an actual infection, but there's just not the infrastructure to treat eveyone with it.
- gus_massa 7y ago
  Read the recomendad schedule by WHO in https://en.wikipedia.org/wiki/Polio_vaccine#Schedule https://en.wikipedia.org/wiki/Polio_vaccine#Schedule * For countries with endemic: case use a few doses of the oral vaccine (that is more powerful) and at least one dose of the injectable version. * For countries without recent cases an a good vaccination coverage: A few injectable doses and later a few oral doses * For countries with very good coverage and low risk of imported cases: Use only the injectable version (that don't cause vaccine derived infections) When your country gets no case for a long enough time and you get a better vaccine coverage, you can "upgrade" the vaccination schedule. (We changed the vaccination schedule a few years ago here in Argentina. Now it is injectable-injectable-oral-oral-oral.)
  - kortex 7y ago
    This answers a long-standing question I have had in the back of my mind: Why aren't oral vaccines more common? I imagine it takes a more aggresive formulation to be effective orally, whereas injection is a straight shot into the fray of the immune system's war on pathongens. These more active forms seem to raise the risk of mutation to active virulence.
    - gus_massa 7y ago
      IANAMD. The polio virus usually attack the intestine, moreover it usually attack only the intestine and cause no symptoms. The normal way of transmission is eating something that is contaminated with poop of an infected person. So it is probably easier to create a vaccine that can be "eaten".
akamaka 7y ago
Using the live vaccine is a trade-off, but there is clear roadmap to eliminate the need for it, one that requires coordinated global surveillance and decision-making. The global strategy for all areas that have eradicated wild polio viruses is to switch from using OPV with live attenuated polio virus to IPV with the killed virus. On April 26, 2016, health authorities around the world implemented a global synchronous switch in which all trivalent oral polio stocks – containing all three strains of the virus – were destroyed to prevent any form of the live type 2 vaccine circulating again. Only a bivalent oral polio vaccine containing the live weakened type 1 and type 3 viruses has been used since then along with the trivalent IPV containing killed strains of all three types of viruses. https://www.google.ca/amp/s/amp.scroll.in/pulse/910881/polio-vaccine-shortages-pose-a-great-risk-to-children-even-if-india-is-polio-free https://www.google.ca/amp/s/amp.scroll.in/pulse/910881/polio...
EGreg 7y ago
We have to make sure people can afford the original Salk vaccine (which is totally inert) instead of the dangerous oral replacement one invented decades later. As is often the case it’s about affordability
- Fomite 7y ago
  It's also much easier to administer, which matters a great deal in many of these settings.
deleted 7y ago
[deleted]
s1k3b8 7y ago
> If that’s true, at what point do we stop vaccinating for it? We stop when we have a way to actually cure the disease or we create a society where people aren't living on top of each other. Just like industrial farming requires mass vaccination and heavy antibiotic use due to high animal concentration, humans need to be vaccinated since industrial society requires massive concentration of people in urban areas. In a 100 years, if medical science can identify vulnerable individuals or actually cure these diseases, we won't need mass vaccination. But until then mass vaccination is the only option. Current scientific knowledge doesn't allow us to keep tens of millions of people in a small area without vaccination.
- adrianN 7y ago
  Diseases were doing pretty well even before tens of millions of people were living in close proximity.
  - s1k3b8 7y ago
    Sure. But diseases do even better when people are concentrated, especially infectious diseases which are the prime targets of vaccines.
bobbylarrybobby 7y ago
We never stop vaccinating for it. If we stop, polio will resurge. It’s unfortunate that people get polio from the vaccine, but it’s worth it because everyone else who gets vaccinated can’t get polio.
- gizmo686 7y ago
  Unless it is erradicated. Smallpox hasn't resurged yet, and we stopped vaccinating against it.
Fomite 7y ago
We stop when it's eradicated.
- 3fe9a03ccd14ca5 7y ago
  There’s no free lunch. Where do you draw the line? Or does the end justify the means and therefore it doesn’t matter how many contract polio from the vaccine? Right now the vaccine is the largest risk of catching polio.
  - solveit 7y ago
    This seems like handwringing for the sake of handwringing because if we stop using the vaccine, polio will return to infect millions. There are interesting ethical debates to be had on vaccination but this is not one of them.
Fomite 7y ago
One of the things I dislike about this "dilemma" is playing it off like it's unexpected. This was true for Smallpox. This will be true for any disease as it approaches eradication if the vaccine isn't 100% side-effect free.
- makomk 7y ago
  No, this wasn't true for smallpox. The smallpox vaccine didn't use the smallpox virus - it used a related virus which isn't very effective at infecting humans and doesn't seem to have been able to easily mutate into something that was. While smallpox vaccination isn't risk-free and there is the occasional incident of the vaccine virus spreading to family members of US soldiers and causing serious health problems, it can't turn back into smallpox. The fact that the symptoms are so obvious and reliable probably helps here too.
  - Fomite 7y ago
    Smallpox has an exceptionally high side effect rate. And that was what I was talking about. "Adverse Outcome From Vaccine" > "Adverse Outcome from Disease" as a general phenomenon.

tyingq 7y ago

To be clear, it's the cheap, oral, live virus polio vaccine that's causing the problem. They don't use that in the US, at all, and we don't have the issue. We don't need to stop polio vaccination...we need to find a reasonable way to replace the low budget version.

EGreg 7y ago
I don’t know why you are being downvoted, what you said is entirely correct AND cuts through the confusion. People need to realize that there are different Polio vaccines and the original Salk vaccine has zero chance of infecting people with Polio.
- akamaka 7y ago
  I downvoted because it’s not correct to suggest that OPV is being used because it is a “low budget version”. In fact, both types of vaccines are being given to children in high-risk countries, as part of the transition away from the live vaccine. In countries with endemic polio or where there is a high risk of imported cases, the WHO recommends OPV vaccine at birth followed by a primary series of 3 OPV and at least one IPV doses starting at 6 weeks of age. https://en.m.wikipedia.org/wiki/Polio_vaccine https://en.m.wikipedia.org/wiki/Polio_vaccine
  - tyingq 7y ago
    "The IPV that has been used in the United States since 1987 is as effective as OPV for preventing polio" https://www.cdc.gov/vaccines/vpd/polio/public/index.html https://www.cdc.gov/vaccines/vpd/polio/public/index.html "Unfortunately, IPV costs considerably more than OPV per dose ($3-5 vs $0.12 on the subsidized world market). Because the WHO and most countries have plans to continue vaccination for at least 10 years after eradication, there will continue to be a market for the vaccine. Because of the high cost of the IPV, efforts are underway to derive improved and less expensive IPV vaccines." http://grantome.com/grant/NIH/R44-AI120260-02 http://grantome.com/grant/NIH/R44-AI120260-02 "One hundred twenty-six low- and middle Income countries will start to use IPV, which is injected, in a single dose, in addition to the oral polio vaccine (OPV). OPV will gradually be phased out, based on certain epidemiologic triggers. The previous price was a major barrier to making this shift. The shift is needed because, for eradication to occur, the polio virus needs to be gone from people, labs, sewage, etc. – i.e. the places in which vaccine-derived polio virus can survive, mutate and cause disease. IPV is ‘inactivated’, and does not carry risk of polio infection to people who are not vaccinated." https://blogs.unicef.org/blog/lowest-ever-prices-for-polio-vaccines/ https://blogs.unicef.org/blog/lowest-ever-prices-for-polio-v... The WHO only recommends OPV because of the low cost.
    - akamaka 7y ago
      IPV induces very low levels of immunity in the intestine. As a result, when a person immunized with IPV is infected with wild poliovirus, the virus can still multiply inside the intestines and be shed in the faeces, risking continued circulation. “...as IPV does not stop transmission of the virus, OPV is used wherever a polio outbreak needs to be contained, even in countries which rely exclusively on IPV for their routine immunization programme. Once polio has been eradicated, use of all OPV will need to be stopped to prevent re-establishment of transmission due to VDPVs.” http://polioeradication.org/polio-today/polio-prevention/the-vaccines/ipv/ http://polioeradication.org/polio-today/polio-prevention/the...
  - onetimemanytime 7y ago
    well it is correct: "But the injectable polio vaccine (IPV) is a better way to inoculate children against the disease: it is safer because it does not carry the live virus. Unhappily, it is also more expensive." https://www.economist.com/feast-and-famine/2013/07/19/injecting-competition https://www.economist.com/feast-and-famine/2013/07/19/inject... Still, now that price has dropped to less than $1 per dose, I am sure rich governments or simple rich people can foot the bill.
akamaka 7y ago
The live vaccine is not simply a “low budget version”, it’s more effective.
- tyingq 7y ago
  It is not.
  - Fomite 7y ago
    There's a number of reasons the live polio vaccine is preferred in developing countries. The biggest is that the OPV vaccine, as the name suggests, is oral. You don't need needles, which means it's easier to mass administer, you don't have to deal with sharps, etc. I think people vastly underestimate the logistical difficulties of delivering vaccines, especially injectables that require a cold chain like IPV. It also sheds, which is good if you're struggling with vaccine coverage. Whether this is a downside or not is a highly dynamic question - as we get closer, the side effects become a bigger deal, but part of the reason they're a big deal is because WT polio is so heavily suppressed.
  - milankragujevic 7y ago
    See this link: https://en.wikipedia.org/wiki/Attenuated_vaccine#Advantages https://en.wikipedia.org/wiki/Attenuated_vaccine#Advantages Advantages of an attenuated vaccine: - Activates all phases of the immune system - Provides more durable immunity; boosters are required less frequently [other are mainly logistics] The disadvantage is that it may cause a reversion to virulence in 3 per 1 000 000 doses given. And it cannot be used in immunocompromised individuals.

makomk 7y ago

That's the truly nasty part of this dilemma: we can't stop vaccinating for it. People who haven't been vaccinated are most at risk of being infected due to the polio vaccine, since the vaccine-derived strains spread from person to person just like the wild polio that they almost eliminated and become more dangerous as they do so. In order to keep those infections under control people are being vaccinated on a massive scale, which works in the short term but spreads massive amounts of the vaccine poliovirus which will cause infections further down the line. The injectable polio vaccination might offer a solution since it uses a dead virus that can't cause an actual infection, but there's just not the infrastructure to treat eveyone with it.

gus_massa 7y ago
Read the recomendad schedule by WHO in https://en.wikipedia.org/wiki/Polio_vaccine#Schedule https://en.wikipedia.org/wiki/Polio_vaccine#Schedule * For countries with endemic: case use a few doses of the oral vaccine (that is more powerful) and at least one dose of the injectable version. * For countries without recent cases an a good vaccination coverage: A few injectable doses and later a few oral doses * For countries with very good coverage and low risk of imported cases: Use only the injectable version (that don't cause vaccine derived infections) When your country gets no case for a long enough time and you get a better vaccine coverage, you can "upgrade" the vaccination schedule. (We changed the vaccination schedule a few years ago here in Argentina. Now it is injectable-injectable-oral-oral-oral.)
- kortex 7y ago
  This answers a long-standing question I have had in the back of my mind: Why aren't oral vaccines more common? I imagine it takes a more aggresive formulation to be effective orally, whereas injection is a straight shot into the fray of the immune system's war on pathongens. These more active forms seem to raise the risk of mutation to active virulence.
  - gus_massa 7y ago
    IANAMD. The polio virus usually attack the intestine, moreover it usually attack only the intestine and cause no symptoms. The normal way of transmission is eating something that is contaminated with poop of an infected person. So it is probably easier to create a vaccine that can be "eaten".

akamaka 7y ago

Using the live vaccine is a trade-off, but there is clear roadmap to eliminate the need for it, one that requires coordinated global surveillance and decision-making. The global strategy for all areas that have eradicated wild polio viruses is to switch from using OPV with live attenuated polio virus to IPV with the killed virus. On April 26, 2016, health authorities around the world implemented a global synchronous switch in which all trivalent oral polio stocks – containing all three strains of the virus – were destroyed to prevent any form of the live type 2 vaccine circulating again. Only a bivalent oral polio vaccine containing the live weakened type 1 and type 3 viruses has been used since then along with the trivalent IPV containing killed strains of all three types of viruses. https://www.google.ca/amp/s/amp.scroll.in/pulse/910881/polio-vaccine-shortages-pose-a-great-risk-to-children-even-if-india-is-polio-free https://www.google.ca/amp/s/amp.scroll.in/pulse/910881/polio...

EGreg 7y ago

We have to make sure people can afford the original Salk vaccine (which is totally inert) instead of the dangerous oral replacement one invented decades later. As is often the case it’s about affordability

Fomite 7y ago
It's also much easier to administer, which matters a great deal in many of these settings.

deleted 7y ago

[deleted]

s1k3b8 7y ago

> If that’s true, at what point do we stop vaccinating for it? We stop when we have a way to actually cure the disease or we create a society where people aren't living on top of each other. Just like industrial farming requires mass vaccination and heavy antibiotic use due to high animal concentration, humans need to be vaccinated since industrial society requires massive concentration of people in urban areas. In a 100 years, if medical science can identify vulnerable individuals or actually cure these diseases, we won't need mass vaccination. But until then mass vaccination is the only option. Current scientific knowledge doesn't allow us to keep tens of millions of people in a small area without vaccination.

adrianN 7y ago
Diseases were doing pretty well even before tens of millions of people were living in close proximity.
- s1k3b8 7y ago
  Sure. But diseases do even better when people are concentrated, especially infectious diseases which are the prime targets of vaccines.

bobbylarrybobby 7y ago

We never stop vaccinating for it. If we stop, polio will resurge. It’s unfortunate that people get polio from the vaccine, but it’s worth it because everyone else who gets vaccinated can’t get polio.

gizmo686 7y ago
Unless it is erradicated. Smallpox hasn't resurged yet, and we stopped vaccinating against it.

Fomite 7y ago

We stop when it's eradicated.

3fe9a03ccd14ca5 7y ago
There’s no free lunch. Where do you draw the line? Or does the end justify the means and therefore it doesn’t matter how many contract polio from the vaccine? Right now the vaccine is the largest risk of catching polio.
- solveit 7y ago
  This seems like handwringing for the sake of handwringing because if we stop using the vaccine, polio will return to infect millions. There are interesting ethical debates to be had on vaccination but this is not one of them.

Fomite 7y ago

One of the things I dislike about this "dilemma" is playing it off like it's unexpected. This was true for Smallpox. This will be true for any disease as it approaches eradication if the vaccine isn't 100% side-effect free.

makomk 7y ago
No, this wasn't true for smallpox. The smallpox vaccine didn't use the smallpox virus - it used a related virus which isn't very effective at infecting humans and doesn't seem to have been able to easily mutate into something that was. While smallpox vaccination isn't risk-free and there is the occasional incident of the vaccine virus spreading to family members of US soldiers and causing serious health problems, it can't turn back into smallpox. The fact that the symptoms are so obvious and reliable probably helps here too.
- Fomite 7y ago
  Smallpox has an exceptionally high side effect rate. And that was what I was talking about. "Adverse Outcome From Vaccine" > "Adverse Outcome from Disease" as a general phenomenon.