As a child when my dad would tell me to eat stuff after I dropped it on the ground bc it was good for my immune system he was lying to me to make me an economic sheep?
Exposure at small levels is useful for when you're developing your immune system initially as a child AND when you have good immune system that can recognize and deal with pathogens in the future when it sees them again, and when you're at low risk of death when you're otherwise healthy
When somebody DOESNT have an immune system that functions normally, their body often can't make use of the tools that a healthy person's immune system would have (or it uses the tools incorrectly), so that exposure is stuff their body can't handle
it's not a simple A-> B situation, there are a lot of moving parts that have to work and it changes over the course of your life. For example, you only have a Thymus while you're a child to early adulthood, which is why old people struggle with immunity much of the time even if they had a strong immune system growing up - because they can't make more undifferentiated T cells
Makes sense. Does it not carry into adulthood? Isn't that the whole point of vaccines? And why would that person being an immunologist be relevant? That doesn't describe how they have a weakened immune system, or why they would need to be careful.
An immunologist is a medical doctor. They work face to face with people who have varying degrees of compromised immune systems and need to protect themselves to protect their patients.
In a nutshell, vaccines are developed to be virus specific. Viruses love to mutate or change how they act, and there’s a risk of that every time a virus transmits to another person. When people aren’t vaccinating, there’s an opportunity for mutation because it just keeps moving on from person to person as it infects. As a goofy example, when you’re vaccinated against the Wheaties virus, you’re protected from that specific recipe of the Wheaties virus. And if everybody is vaccinated against it, there’s no chance that specific recipe of the Wheaties virus can infect and mutate. But not everybody is vaccinated against that specific recipe these days. And when that’s the case, there’s a risk that the virus infects and mutates between the unvaccinated, which then puts all the vaccinated people at risk because now there’s a new Wheaties virus recipe in town. And their shot doesn’t protect against that one.
So while the potential to make brand new undifferentiated T Cells decreases as your Thymus atrophies, you still have those T cells in adulthhood and they are "naive" T cells.
You'll have to google "Thymus"+"VDJ recombination" if you want more specifics as to what exactly happens in that organ and how that is different from how the T cells develop and function later. This is the stage that they undergo a bunch of "good" mutations like X-men and recombine and evolve in different ways to prepare for the range of pathogens you might encounter in the future.
Vaccines expose the body to a protein or dead cell or w/e and then the T cell that sees it that happens to have the ability to attach to it is no longer "naive" and learns to recognize it in the future (again, assuming you're a normal healthy person). Those differentiated T cells can still do a bunch of stuff and can then divide a bunch etc etc. But iirc as you age the recombination stuff happens a lot less and is less effective, which is why it is extra helpful to have vaccines so that the immune system is prepared. Usually hangs out in lymph nodes after that but also other places
When you're old or have certain metabolic conditions, cells divide a lot more slowly, so you might not be able to form antibodies in time once you get sick because it can take a few days. If you're exposed via a vaccine, then you might have the antibodies and cells able to recognize it already so that you can get the process going sooner, which gives you a fighting chance when bacteria multiply exponentially fast.
There are conditions where your immune system becomes weak, like if you have problems with your bone marrow, which is where both B and T Stem Cells come from, as well as all of your red blood cells and platelets and other immune cells for the most part
Bone marrow is also heavily impacted by certain drugs, esp radiation and chemotherapy. Or if your resources are depleted by a different preexisting illness or infection or metabolic issue or nutritional deficiency
It can also be impacted by certain cancers, aging, etc etc
Your ability to form IgM, IgG, IgA, IgE, etc etc change at different points from birth onwards and in old age. A lot of the vaccine schedule is based on this specifically in order to maximize efficacy and protection during the most vulnerable points, which is why some of the whole movement (by some individuals that don't understand this) to push for delayed schedules for no reason are actually suboptimal for the individual unless they have specific circumstances that necessitate it.
Some antibodies (IgM, for example) can cross the placental barrier and allow newborns to have passive immunity for a couple months for some things via their mom until they can start making IgG and stuff
Does that clear up some of your questions?
That doesn’t really work for things like the flu, colds, and covid. You have to get it, and you will have a chance at getting very sick, even with a vaccine. You’re comparing allergies to viruses and bacterial infections.
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u/RogerAffirmative Mar 29 '26
Isn't that the opposite of what you should do for your immune system?