4 ms·

I'm reminded of how polio paralysis only really became a thing with improved hygiene. Polio, for some reason, almost never paralyzes newborns. Until the late

by retrac 4y ago

I'm reminded of how polio paralysis only really became a thing with improved hygiene. Polio, for some reason, almost never paralyzes newborns. Until the late 19th century it was implausible to not get infected shortly after birth, and then constantly have that immunity built up with reinfection. But toilets and sewers changed that, and a child might not catch it until much older, where paralysis is a risk. Similarly someone in adulthood might have little immunity left, get a huge exposure eventually, and then develop neurological symptoms.

Vecr 4y ago
This is correct, not sure why it was downvoted. I think a major reason why people did not get very sick from poliovirus when very young is because of maternal IgG passed through the placenta before birth, and maternal IgA (edit, sorry, probably IgG through breast milk as well) passed through breast milk. This only lasts for six months and even by then it's waning, so children should get vaccinated with trivalent eIPV (enhanced Inactivated Polio Vaccine) as soon as their immune system is developed enough, probably by four months of age in enough cases to start giving the first dose. Some countries can't handle the cost and logistics of giving safe injections of eIPV, but you can't give multiple serotypes of OPV (Oral Polio Vaccine) at the same time because there is a dominance hierarchy that interferes with generating immunity against all serotypes, so at least one dose of eIPV should be used before starting OPV if at all possible. Polio has three serotypes without long-term protective cross reactivity, so you can't rely on natural infection to prevent future disease (possibly as a teenager or adult) caused by a different serotype.
Brybry 4y ago
Infant and youth mortality were really high until the 20th century[1] Sometimes they weren't even named[2] or the deaths recorded[3]. [1] https://ourworldindata.org/uploads/2019/06/Mortality-rates-of-children-over-last-two-millennia.png https://ourworldindata.org/uploads/2019/06/Mortality-rates-o... [2] https://digitalcommons.kennesaw.edu/cgi/viewcontent.cgi?article=1012&context=jpps https://digitalcommons.kennesaw.edu/cgi/viewcontent.cgi?arti... [3] https://www.jstor.org/stable/2173612 https://www.jstor.org/stable/2173612
- retrac 4y ago
  Yes, but that doesn't explain the steady increase in adult and older child polio paralysis seen in the first half of the 20th century. Cases peaked as the vaccine was introduced.
  - Pyramus 4y ago
    Sorry I don't know much about polio and don't fully understand the argument - how does it affect the overall risk-benefit ratio of Polio vaccination? Any vaccine will have side effects negatively for that matter, how is Polio different in that regard?
    - retrac 4y ago
      I would think it strengthens the argument for vaccination. Adults and older children are at great risk of serious illness due to lack of childhood immunity. If none of us had polio vaccines, it would probably behave today much as it did in the mid-20th century USA, with periodic waves of outbreak that would leave dozens or hundreds dead and tens of thousands disabled.
hammock 4y ago
I have seen this perspective on polio before, with data. Can’t find it now, but wanted to add my experience for the downvoters.
jjt-yn_t 4y ago

by retrac 4y ago

Vecr 4y ago

This is correct, not sure why it was downvoted. I think a major reason why people did not get very sick from poliovirus when very young is because of maternal IgG passed through the placenta before birth, and maternal IgA (edit, sorry, probably IgG through breast milk as well) passed through breast milk. This only lasts for six months and even by then it's waning, so children should get vaccinated with trivalent eIPV (enhanced Inactivated Polio Vaccine) as soon as their immune system is developed enough, probably by four months of age in enough cases to start giving the first dose. Some countries can't handle the cost and logistics of giving safe injections of eIPV, but you can't give multiple serotypes of OPV (Oral Polio Vaccine) at the same time because there is a dominance hierarchy that interferes with generating immunity against all serotypes, so at least one dose of eIPV should be used before starting OPV if at all possible. Polio has three serotypes without long-term protective cross reactivity, so you can't rely on natural infection to prevent future disease (possibly as a teenager or adult) caused by a different serotype.

Brybry 4y ago

Infant and youth mortality were really high until the 20th century[1] Sometimes they weren't even named[2] or the deaths recorded[3]. [1] https://ourworldindata.org/uploads/2019/06/Mortality-rates-of-children-over-last-two-millennia.png https://ourworldindata.org/uploads/2019/06/Mortality-rates-o... [2] https://digitalcommons.kennesaw.edu/cgi/viewcontent.cgi?article=1012&context=jpps https://digitalcommons.kennesaw.edu/cgi/viewcontent.cgi?arti... [3] https://www.jstor.org/stable/2173612 https://www.jstor.org/stable/2173612

retrac 4y ago
Yes, but that doesn't explain the steady increase in adult and older child polio paralysis seen in the first half of the 20th century. Cases peaked as the vaccine was introduced.
- Pyramus 4y ago
  Sorry I don't know much about polio and don't fully understand the argument - how does it affect the overall risk-benefit ratio of Polio vaccination? Any vaccine will have side effects negatively for that matter, how is Polio different in that regard?
  - retrac 4y ago
    I would think it strengthens the argument for vaccination. Adults and older children are at great risk of serious illness due to lack of childhood immunity. If none of us had polio vaccines, it would probably behave today much as it did in the mid-20th century USA, with periodic waves of outbreak that would leave dozens or hundreds dead and tens of thousands disabled.

hammock 4y ago

I have seen this perspective on polio before, with data. Can’t find it now, but wanted to add my experience for the downvoters.

jjt-yn_t 4y ago