Can a pathogenic organism be totally resistant to the human immune system? For the purpose of this question, the organism in question must cause a disease.

Examples of organisms that would qualify as totally resistant:

Pathogenic organisms that are completely undetected by the immune system while the disease that they cause runs its course.

Pathogenic organisms that, even if detected, are completely invulnerable to the immune system. For instance, macrophages and other immune cells would not be able to destroy even one cell of such an organism.

Is it possible for such a pathogen to exist? Are there any such pathogens? (For the purpose of this question, the HIV and diseases that only manifest in immuno-compromised individuals do not count)

  • $\begingroup$ The problem is much of the immune system is passive, that is it resists everything equally. $\endgroup$
    – John
    Commented Jul 3, 2019 at 13:46
  • $\begingroup$ ???? The HIV attacks the immune system. The infection is obviously easier in already immuno-compromised individuals... $\endgroup$ Commented Jul 8, 2020 at 14:12

1 Answer 1


I can't think of any pathogenic organisms that are completely resistant to the immune system. Some bacteria that cause chronic diseases (e.g. tuberculosis) are relatively resistant, and a handful of viruses (e.g. spumaviruses) are relatively invisible, but the nature of pathogen transmission would mean that completely resistant organisms would spread through a population pretty fast and we'd know about it.

Pathogenic prion agents, like scrapie and Creutzfeld-Jacob disease, are essentially invisible to the immune system, and can be transmitted; but they aren't pathogenic organisms. They might be the closest to your description though.


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