3 ms·

You know what they say: extraordinary claims require extraordinary evidence. Based on what data do you make this statement?

rowanseymour 6y ago
Many poorer countries have relied on cheaper forms of the polio vaccine with a weakened virus, which can sometimes cause small outbreaks. Ironically this fact is often used the anti-vaxxers as an argument against vaccines.. when it's only been true because polio vaccination has been so successful at eradicating the real virus which was causing considerably more problems.
- tialaramex 6y ago
  The oral vaccine is not only cheaper it also works better. This means if you have endemic Polio it can make good sense to deploy OPV even knowing that there is risk of it reverting. The rich industrialised countries that switched to the boring inactivated vaccine don't have endemic Polio so the risk structure is different (as well as being able to afford the more expensive product). It's not entirely clear why OPV is more effective, but perhaps it matters that you eat it (when I was a child it was administered as a sugar lump) and so the attenuated virus is entering the body via the gut, exactly where a real working polio virus infects people. The more expensive killed vaccine is injected into a muscle instead.
tgb 6y ago
I was surprised too, but the WHO backs up the existence of "vaccine-associated paralytic polio", though I'm finding some conflicting numbers it's on the order of 1 in a million paralysis cases per vaccine. That presumably outpaces wild polio paralysis cases due to the non-existence of wild polio, in certain regions. WHO evens says it's possible for others to catch the paralysis from close contact with a recently-vaccinated individual, though it's never spread beyond that. https://www.who.int/immunization/diseases/poliomyelitis/endgame_objective2/oral_polio_vaccine/VAPPandcVDPVFactSheet-Feb2015.pdf https://www.who.int/immunization/diseases/poliomyelitis/endg...
- nsgi 6y ago
  cVDPV is the one that's the big problem. You can see how many cases are occurring here: http://polioeradication.org/polio-today/polio-now/this-week/ http://polioeradication.org/polio-today/polio-now/this-week/
- makomk 6y ago
  There are two similar but crucially different problems with the current live polio vaccine that both end in cases of paralytic polio. Vaccine-associated paralytic polio is a very rare complication where someone gets full-on paralytic polio as a result of being vaccinated; it can also happen to people who catch the vaccine virus from someone else rather than from vaccination, but it's just as rare there. Circulating vaccine-derived poliovirus is the one that's really nasty for elimination efforts - once the vaccine poliovirus circulates unchecked within a community for a while, it mutates and basically turns back into full-on real, unweakened polio in all its contagious paralytic awfulness, at which point anyone who's exposed to it is at much higher risk. As I understand it, cVDPV makes up the large majority of both polio cases and paralytic polio cases across the globe these days, and 100% of cases in Africa now the wild-type virus has been eliminated from there. If VAPP was the only problem it could easily be fixed just by eliminating polio and then ending the live vaccination program. Unfortunately, that would make the cVDPV problem worse because it's an actual, circulating virus that primarily infects people who haven't been vaccinated, and ending vaccination would increase the number of people at risk from it. As the document from 2015 you've found suggests, the folks trying to eliminate polio hoped that if they phased out the live oral polio vaccine carefully and in well-coordinated ways they could avoid major cVDPV outbreaks afterwards. This doesn't seem to have worked out as well as they hoped back then. In particular, this article and HN discussion from a few months ago which someone helpfully dug up is mostly about the failure of this endgame plan in Africa: https://news.ycombinator.com/item?id=21920406 https://news.ycombinator.com/item?id=21920406
ars 6y ago
Data: https://en.wikipedia.org/wiki/Polio_eradication#2020 https://en.wikipedia.org/wiki/Polio_eradication#2020 In 2020 there were 102 wild cases, and 295 vaccine derived cases. You have to go back to 2016 for wild cases to outnumber vaccine cases. He's getting downvoted for the tone: People are assuming he is discrediting the vaccine by saying that. I personally don't see that implication, I just see a bare, and correct, fact.
- gus_massa 6y ago
  Short version of the data: wild vaccine-derived 2015: 74 32 2016: 37 5 2017: 22 96 2018: 33 104 2019: 165 365 2020: 102 291 >>> more children had been getting polio from polio vaccines than getting it in the wild for a long time I think that it is misleading to call the last four years "a long time".

rowanseymour 6y ago

Many poorer countries have relied on cheaper forms of the polio vaccine with a weakened virus, which can sometimes cause small outbreaks. Ironically this fact is often used the anti-vaxxers as an argument against vaccines.. when it's only been true because polio vaccination has been so successful at eradicating the real virus which was causing considerably more problems.

tialaramex 6y ago
The oral vaccine is not only cheaper it also works better. This means if you have endemic Polio it can make good sense to deploy OPV even knowing that there is risk of it reverting. The rich industrialised countries that switched to the boring inactivated vaccine don't have endemic Polio so the risk structure is different (as well as being able to afford the more expensive product). It's not entirely clear why OPV is more effective, but perhaps it matters that you eat it (when I was a child it was administered as a sugar lump) and so the attenuated virus is entering the body via the gut, exactly where a real working polio virus infects people. The more expensive killed vaccine is injected into a muscle instead.

tgb 6y ago

I was surprised too, but the WHO backs up the existence of "vaccine-associated paralytic polio", though I'm finding some conflicting numbers it's on the order of 1 in a million paralysis cases per vaccine. That presumably outpaces wild polio paralysis cases due to the non-existence of wild polio, in certain regions. WHO evens says it's possible for others to catch the paralysis from close contact with a recently-vaccinated individual, though it's never spread beyond that. https://www.who.int/immunization/diseases/poliomyelitis/endgame_objective2/oral_polio_vaccine/VAPPandcVDPVFactSheet-Feb2015.pdf https://www.who.int/immunization/diseases/poliomyelitis/endg...

nsgi 6y ago
cVDPV is the one that's the big problem. You can see how many cases are occurring here: http://polioeradication.org/polio-today/polio-now/this-week/ http://polioeradication.org/polio-today/polio-now/this-week/
makomk 6y ago
There are two similar but crucially different problems with the current live polio vaccine that both end in cases of paralytic polio. Vaccine-associated paralytic polio is a very rare complication where someone gets full-on paralytic polio as a result of being vaccinated; it can also happen to people who catch the vaccine virus from someone else rather than from vaccination, but it's just as rare there. Circulating vaccine-derived poliovirus is the one that's really nasty for elimination efforts - once the vaccine poliovirus circulates unchecked within a community for a while, it mutates and basically turns back into full-on real, unweakened polio in all its contagious paralytic awfulness, at which point anyone who's exposed to it is at much higher risk. As I understand it, cVDPV makes up the large majority of both polio cases and paralytic polio cases across the globe these days, and 100% of cases in Africa now the wild-type virus has been eliminated from there. If VAPP was the only problem it could easily be fixed just by eliminating polio and then ending the live vaccination program. Unfortunately, that would make the cVDPV problem worse because it's an actual, circulating virus that primarily infects people who haven't been vaccinated, and ending vaccination would increase the number of people at risk from it. As the document from 2015 you've found suggests, the folks trying to eliminate polio hoped that if they phased out the live oral polio vaccine carefully and in well-coordinated ways they could avoid major cVDPV outbreaks afterwards. This doesn't seem to have worked out as well as they hoped back then. In particular, this article and HN discussion from a few months ago which someone helpfully dug up is mostly about the failure of this endgame plan in Africa: https://news.ycombinator.com/item?id=21920406 https://news.ycombinator.com/item?id=21920406

ars 6y ago

Data: https://en.wikipedia.org/wiki/Polio_eradication#2020 https://en.wikipedia.org/wiki/Polio_eradication#2020 In 2020 there were 102 wild cases, and 295 vaccine derived cases. You have to go back to 2016 for wild cases to outnumber vaccine cases. He's getting downvoted for the tone: People are assuming he is discrediting the vaccine by saying that. I personally don't see that implication, I just see a bare, and correct, fact.

gus_massa 6y ago
Short version of the data: wild vaccine-derived 2015: 74 32 2016: 37 5 2017: 22 96 2018: 33 104 2019: 165 365 2020: 102 291 >>> more children had been getting polio from polio vaccines than getting it in the wild for a long time I think that it is misleading to call the last four years "a long time".