[Fillyjonk]

<p>I'm just curious, from a scientific perspective. </p>
<p> </p>
<p> </p>
<p>I thought adult immune systems were generally stronger and more robust than young kid ones, so I'm interested in why the diseases should be more dangerous in adulthood. </p>
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<p>(and can I say, I so appreciate having a space where I feel i can ask this!)</p>
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<p>TIA x</p>

 

[hushpuppy]

<p>That's a really good question. I don't know the answer for all infectious diseases, but perhaps it's something to do with how strong the adult immune system is? The immune response causes many symptoms rather than the pathogen itself (like fever, muscle pain, nausea, shock, even some viral rashes) so it makes sense that in someone with a strong immune system the disease would be more severe. That also explains why Hepatitis B is more likely to be chronic in children than adults... it's the immune system that causes the liver damage, so while the adult response is more aggressive, it clears the virus relatively quickly. In children the liver is less likely to be damaged in the acute phase but the virus persists, causing progressive liver disease over time.</p>
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<p>Hopefully someone more knowledgeable than me can pitch in!</p>

 

[Fillyjonk]

<p>thanks  that was my initial assumption but-why then are <em>most</em> diseases in adults <em>less</em> serious? </p>

 

[hushpuppy]

<p>I guess it just depends how each specific microorganism interacts with the host. Some disproportionately affect the very young and very old with their weaker defenses, as the infection can more easily get out of hand before the immune system can control it. Others might be harder on people with strong immune systems as they trigger an inflammatory response that causes unpleasant and/or life threatening complications. That's just speculation on my part though... It's a really interesting question.</p>

 

[teacozy]

<p>Very interesting question! I'm not sure what the answer is but I remember reading about the 1918 flu pandemic and how it was so unusual in that it was so much more dangerous for young adults than it was for children or the elderly.  Obviously chickenpox/measles are not the same thing as the flu but I still thought this was an interesting explanation as to why they think it happened that way</p>
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<p>"Most influenza outbreaks disproportionately kill juvenile, elderly, or already weakened patients; in contrast the 1918 pandemic killed predominantly previously healthy young adults. Modern research, using virus taken from the bodies of frozen victims, has concluded that the virus kills through a <a href="http://en.wikipedia.org/wiki/Cytokine_storm" style="background-image:none;color:rgb(11,0,128);" target="_blank" title="Cytokine storm">cytokine storm</a> (overreaction of the body's <a href="http://en.wikipedia.org/wiki/Immune_system" style="background-image:none;color:rgb(11,0,128);" target="_blank" title="Immune system">immune system</a>). The strong immune reactions of young adults ravaged the body, whereas the weaker immune systems of children and middle-aged adults resulted in fewer deaths among those groups.<sup id="user_cite_ref-Barry_book_11-0"><a href="http://en.wikipedia.org/wiki/1918_flu_pandemic#cite_note-Barry_book-11" style="background-image:none;color:rgb(11,0,128);white-space:nowrap;" target="_blank">[11]</a></sup></p>
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<p><a href="http://en.wikipedia.org/wiki/1918_flu_pandemic" target="_blank">http://en.wikipedia.org/wiki/1918_flu_pandemic</a></p>
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<p>Just food for thought...</p>

 

[cwill]

<p>^^^ That's exactly the first thing that came to my mind teacozy!</p>
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<p>I think there are multiple things going on so it's not just a simple answer.  With chicken pox, for example, many of the complications that adults have (higher fever, more severe rash, encephalitis) can be attributed to a "too strong" inflammatory response.  On the other hand, some of the complications (pneumonia and secondary skin infections) are associated with lifestyle habits such as smoking or occur more often in immunocompromised adults.  So there's not just one answer.</p>
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<p>An interesting point, while I was looking into chicken pox, was that while it is a childhood disease in developed countries; in developing countries, it often occurs later in adolescence and adulthood.  Perhaps due to high infection rates with respiratory herpes - competition between viruses, maybe?  There's some thought that it might be climate-related as well.</p>

 

[pepperedmoth]

<p>And some illnesses are more severe in children than in adults, like pertussis. </p>
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<p>I don't think it's so cut and dry. </p>

 

[erigeron]

<p>This same topic was posted in INV and somebody there pointed out that when kids are sick generally they are kept home and get to stay in bed, take it easy, be fed, etc. while when adults are sick we are often still trying to work, take care of our kids, keep the house clean, and all the normal things we do--so maybe that could be a contributing factor as well.</p>

 

[USAmma]

<p>Great question! I remember sailing through my own chicken pox when I was around four. My 18 year old aunt was visiting and caught it and was very, very sick. And my dh also got it at around age 19 and he said he was seriously ill, almost went to the hospital and long recovery time.</p>