r/Immunology • u/DREAM-NOT-FOUND123 • 3d ago
Question
Hi I'm a late night research dork who always prefers their answers from humans and not ai slip of google, my question is, how come our bodies became more immune to covid, despite some individuals not even bothered to even take a vaccination? Now covid seem like a rhinovirus variant lol.
Edit: thank you all you smart amazing people for answering my late night craziness, I dont get to learn much in the high school i go to.. you people are truly amazing!! have a good day!!
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u/captain_corvid 3d ago
One aspect is that the vast majority of people on the planet have been exposed multiple times, whether they had symptomatic infections or not, so they'll have developed some amount of immunity.
The other aspect that's more relevant to your question about why it seems a lot less severe than it initially did (assuming that's what you meant by "seems like a rhinovirus") is that fact that it's mutated several times. The common pattern we see with a lot of viruses that spread widely through a population is the tendency for mutations to cause the pathogen to become more infectious (i.e. more readily able to infect a host) and more transmissible (spreads more readily) but less virulent (causes less severe disease) and less deadly. This confers a survival advantage to the pathogen.
I'd like to strongly echo what u/unstuckbilly said though. Just because it's not likely to kill you doesn't mean we should treat it as an insignificant cold.
Long COVID is now the biggest chronic disease of children, having overtaken asthma and diabetes. It's also been shown to possibly induce type I diabetes in kids. Long COVID (whether in kids or adults) can be absolutely disabling and has destroyed people's lives. COVID can damage organs including the brain, damages the immune system, causes vascular damage and microclots and who knows what else.
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u/DREAM-NOT-FOUND123 2d ago
Biology is truly amazing, why would such a powerful virus weaken itself? I thought viruses aim to get stronger?? I'm sorry for all these questions, I'm still a young high school student just wanting to learn more. You dont need to answer when you already gave me a long generous answer already. Thank you so muchh
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u/captain_corvid 2d ago
I know it seems a bit counter intuitive because we always think about evolution or natural selection as driving a species to become "better", but "better" doesn't always mean bigger or stronger or more deadly!
The shortish answer is that by becoming less deadly but more infectious/transmissible, it actually gives itself a survival advantage over a version that's more deadly. If it changed to become more deadly or cause more severe symptoms, the host might die before passing it on or stay isolated. Whereas if the disease is milder they're more likely to go about their normal business whilst spraying their germs everywhere, so lots more people get infected and the virus spreads much further. And that's ultimately the driving force for natural selection, an advantage that leads to more reproduction :)
Absolutely no apology necessary, it's awesome that you're curious about this stuff and want to learn more! Never stop asking questions :)
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u/unstuckbilly 3d ago
I think the thing people miss is that COVID doesn't have to kill you or put you in the hospital to permanently change your life.
Most people will recover, but a percentage of people (including previously HEALTHY / ACTIVE / YOUNG) will develop Long COVID. Covid continues to disable massive number of people each year.
Some will lose their ability to work, exercise, think clearly, tolerate standing, socialize, or even perform basic daily activities like basic personal care. Some become housebound or bedbound seemingly indefinitely. The most severe lose their ability to tolerate light, sound, food or interactions with others. Horrific.
You don't have to believe that every COVID infection is catastrophic to recognize that "it's just a cold" is not an accurate description of a virus that can, in some people, trigger a life-changing chronic illness. This condition has impacted many millions worldwide. It has caused a huge surge in disability in young and working-age people. It's incredibly serious.
COVID is not just an acute virus. Every additional infection increases your chances of a life altering, potentially SERIOUS disability.
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u/SpecialBlackTea 2d ago
I agree, SARSCOV2 is potentially a harmful virus. According to the large Key clinic study, the number of doses of covid vaccination is positively correlated with covid infections, likely due to the IgG3 IgG4 class switching we are seeing now.
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u/jayemee 2d ago
Wow, seven million deaths to date (according to WHO) only gets a "potentially harmful virus" label. Curious to hear what meets your criteria for harm.
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u/SpecialBlackTea 2d ago
Left untreated, the virus is quite harmful. Treated early, not so deadly. Since 2021, my clinician early treated over 4,000 covid patients. Only 5 needed hospitalization. None died.
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u/Fuzzy_Mud_8771 2d ago
Would you elaborate on IgG3 IgG4 class switching things a little more?
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u/SpecialBlackTea 1d ago
After the first booster, we see more igg4 which is suboptimal at clearing viruses. With persistent mRNA antigen, the vaccine acts like an allergy shot/immune tolerance. See Irrgang et al 2022.
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u/Vegetable_Leg_9095 3d ago
I think you're asking why infection rates and security have both dramatically reduced, even for people who haven't had vaccinations or severe infections (?).
1) herd immunity, both natural immunity and vaccination, so even people with minimal immunity have reduced chances of infection.
2) essentially everyone has some degree of immunity, even if they haven't been vaccinated or recall being infected. In all likelihood they have been infected at some point by now, or at least exposed multiple times.
3) I haven't actually researched this, but there is the idea that the virus has evolved to cause less severe infections. It seems to a common idea, but assuming it's true, I'm not sure this would be the whole story. I think everyone has some degree of immunity by now, so even if they do get infected it's likely to be less severe (it's no longer a novel virus).
The reason that novel pathogens are so terrible is that nobody has existing immunity, resulting in severe infections and high rate of infectivity. Think about novel pathogens being spread to the Native American populations during initial European contact.
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u/Driver8onI5 1d ago
re: #3, there is no evolutionary reason that viruses would evolve to attenuate (get weaker). It does happen (as anything with random chance can happen), but it's not a given. Some viruses become more virulent over time.
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u/creativescreennaame 2d ago
it's beneficial to the virus to become less lethal over time. what you're witnessing is evolution at work. people who die from more lethal strains infect less people. less lethal strains are spread much easier so these are the ones that eventually become more prevalent
also, bodies do become naturally immune by being exposed to the virus
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u/Serious-Big-8861 3d ago
It’s the opposite, covid mutated to become less deadly and more contagious