4 ms·

Naturally-occurring herd immunity is a temporary effect. Only artifically-imposed herd immunity (i.e. vaccination) is lasting.

graeme 7y ago
Yes, but unless herd immunity lasts only a couple weeks that shouldn’t be a factor in these Italian analyses. The infection spread over a short period.
ShorsHammer 7y ago
What a ridiculously incorrect statement. SARS back in 2002 only lasted 3 flu seasons before being entirely wiped out naturally. SARS-CoV-2 which we are dealing with here is a related virus. > No cases of the first SARS-CoV have been reported worldwide since 2004. https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndrome https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndr... https://www.nhs.uk/conditions/sars/ https://www.nhs.uk/conditions/sars/
- wtallis 7y ago
  I'm not seeing how the information you cite forms a counterargument against the comment you replied to. Did you mean to post this elsewhere?
  - ShorsHammer 7y ago
    Original comment: > Naturally-occurring herd immunity is a temporary effect. Reply: > No cases of the first SARS-CoV have been reported worldwide since 2004. No I very much intended to write it here. Which part of this interaction needs more explaining?
- endorphone 7y ago
  Naturally? SARS was wiped out through unprecedented containment efforts by a multitude of nations. Its annihilation was very much artificial and was extraordinarily costly.
  - ShorsHammer 7y ago
    It's annihilation was natural and those containment efforts were only put in place originally, most were wound back within a few months and never reinstated as you can see from the timeline, the virus still spread amongst the population.[0] > was extraordinarily costly No it wasn't, the costs were were a rounding error on the global economy scale[1] > The calculations above suggest that the cost in 2003 of SARS for the world economy as a whole are close to $US 40 billion [0] https://en.wikipedia.org/wiki/2002%E2%80%932004_SARS_outbreak https://en.wikipedia.org/wiki/2002%E2%80%932004_SARS_outbrea... [1] https://www.ncbi.nlm.nih.gov/books/NBK92473/ https://www.ncbi.nlm.nih.gov/books/NBK92473/
    - endorphone 7y ago
      I honestly don't even understand what your angle is. I saw elsewhere that you're effectively a COVID-denier, so I suppose this is just more of the same. As to its spread, wherever it was found it was treated as a highly contagious pathogen and extraordinary efforts were exerted. Toronto basically shut down when a cell appeared here. And it worked -- the spread was stopped. If you seriously think that SARS just naturally petered out, you are both a lost cause and seriously ignorant.
- dang 7y ago
  Please don't post in the flamewar style to HN. It doesn't help, and you can make your substantive points without it. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
cma 7y ago
Some diseases become endemic and pervasive in childhood and end up not causing issues in the elderly who already built up their immune system in childhood. Other times an exposure in childhood ends up cross reacting or something and makes things more deadly later on (I think that's one theory for the 1918 flu; elderly and middle age were protected from an earlier flu exposure, 20-30 year olds had exposure in childhood to something different with a shared antigen that ended up making the immune system overreactive and made things more deadly).
btilly 7y ago
I don't know why this comment is being voted down when it is, in fact, correct. Though "temporary" is on a scale proportional to a lifespan. If an epidemic sweeps through and infects most of the "herd", that herd has herd immunity. In time as individuals born and others die, the fraction of the herd that is immune goes down and the herd is vulnerable to the same epidemic. But with vaccination, herd immunity can be sustained indefinitely. With no further epidemics. But, as measles has shown, only as long as a high enough fraction of the herd vaccinates. Of course it is also possible that if enough of the herd is immune for long enough that the epidemic goes extinct. This takes a lot of work but is how we got rid of Smallpox Effective contact tracing and social distancing can achieve the same end, which is how we got rid of SARS.

graeme 7y ago

Yes, but unless herd immunity lasts only a couple weeks that shouldn’t be a factor in these Italian analyses. The infection spread over a short period.

ShorsHammer 7y ago

What a ridiculously incorrect statement. SARS back in 2002 only lasted 3 flu seasons before being entirely wiped out naturally. SARS-CoV-2 which we are dealing with here is a related virus. > No cases of the first SARS-CoV have been reported worldwide since 2004. https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndrome https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndr... https://www.nhs.uk/conditions/sars/ https://www.nhs.uk/conditions/sars/

wtallis 7y ago
I'm not seeing how the information you cite forms a counterargument against the comment you replied to. Did you mean to post this elsewhere?
- ShorsHammer 7y ago
  Original comment: > Naturally-occurring herd immunity is a temporary effect. Reply: > No cases of the first SARS-CoV have been reported worldwide since 2004. No I very much intended to write it here. Which part of this interaction needs more explaining?
endorphone 7y ago
Naturally? SARS was wiped out through unprecedented containment efforts by a multitude of nations. Its annihilation was very much artificial and was extraordinarily costly.
- ShorsHammer 7y ago
  It's annihilation was natural and those containment efforts were only put in place originally, most were wound back within a few months and never reinstated as you can see from the timeline, the virus still spread amongst the population.[0] > was extraordinarily costly No it wasn't, the costs were were a rounding error on the global economy scale[1] > The calculations above suggest that the cost in 2003 of SARS for the world economy as a whole are close to $US 40 billion [0] https://en.wikipedia.org/wiki/2002%E2%80%932004_SARS_outbreak https://en.wikipedia.org/wiki/2002%E2%80%932004_SARS_outbrea... [1] https://www.ncbi.nlm.nih.gov/books/NBK92473/ https://www.ncbi.nlm.nih.gov/books/NBK92473/
  - endorphone 7y ago
    I honestly don't even understand what your angle is. I saw elsewhere that you're effectively a COVID-denier, so I suppose this is just more of the same. As to its spread, wherever it was found it was treated as a highly contagious pathogen and extraordinary efforts were exerted. Toronto basically shut down when a cell appeared here. And it worked -- the spread was stopped. If you seriously think that SARS just naturally petered out, you are both a lost cause and seriously ignorant.
dang 7y ago
Please don't post in the flamewar style to HN. It doesn't help, and you can make your substantive points without it. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html

cma 7y ago

Some diseases become endemic and pervasive in childhood and end up not causing issues in the elderly who already built up their immune system in childhood. Other times an exposure in childhood ends up cross reacting or something and makes things more deadly later on (I think that's one theory for the 1918 flu; elderly and middle age were protected from an earlier flu exposure, 20-30 year olds had exposure in childhood to something different with a shared antigen that ended up making the immune system overreactive and made things more deadly).

btilly 7y ago

I don't know why this comment is being voted down when it is, in fact, correct. Though "temporary" is on a scale proportional to a lifespan. If an epidemic sweeps through and infects most of the "herd", that herd has herd immunity. In time as individuals born and others die, the fraction of the herd that is immune goes down and the herd is vulnerable to the same epidemic. But with vaccination, herd immunity can be sustained indefinitely. With no further epidemics. But, as measles has shown, only as long as a high enough fraction of the herd vaccinates. Of course it is also possible that if enough of the herd is immune for long enough that the epidemic goes extinct. This takes a lot of work but is how we got rid of Smallpox Effective contact tracing and social distancing can achieve the same end, which is how we got rid of SARS.