Affecting immunity and improving immunity are two very different things. Just to be clear, since we are in the Covid community, the Wim Hof method does NOT provide any protection against Covid-19. Again, affecting the immune system and improving immunity are two very different things. I invite you to look at this study, specifically what it concludes in the first paragraph.

In conclusion, we demonstrate that voluntary activation of the sympa-thetic nervous system results in epinephrine release and subsequent suppression of the innate immune response in humans in vivo

Especially this part:

subsequent suppression of the innate immune response in humans

It SUPPRESSES the immune response, not the other way around! It will not provide any protection against Covid or any other disease that requires an immune response!

Like any marketable pseudoscience, the Wim Hof method contains a grain of truth; i.e. that it affects the immune system. The LIE is that it improves the immune system, the truth is that it suppresses it! There's a grain of truth involved, but the lie is all the bullshit that Wim Hof and his team constantly say and imply. It's important to have high standards for medical advice. When someone is lying and strongly implying lies much of the time, it's important to be careful of whatever medical advice they give or imply.