[XorNot]

The immune system does not expend resources on vaccines.

You do not somehow go into deficit by getting a vaccine.

[wizzwizz4]

The immune system does expend resources on vaccines: it makes antibodies, usually has some kind of inflammatory response…. But if a vaccine causes a nutritional deficiency, there's something seriously wrong with your diet.

[XorNot]

This is like saying that balancing while walking expends resources.

Yes it's technically true, but it is also how walking functions regardless of circumstance.