[refurb]

I think what threw me off is the use of the word "immune suppression". That word has a specific meaning when referring to drugs and tends to refer to drugs that to interrupt immune response far upstream. These drugs have severe side effects as your body can't fight invading viruses and bacteria.

I think the difference with cold remedies is that they tend to interfere with immune responses that are far downstream that tend to be more symptomatic, rather than major mechanisms by which the body's immune system works.