Hard to say really, given the pleomorphic nature of pathogens.  What I will say is that regardless of the cause what I would highly recommend (in addition to the aforementioned iodine and silica), that a person take colloidal silver orally and also nebulize regularly with colloidal silver, lobelia and mullein.  In addition, I also highly, highly recommend the Chinese herbal formula Clear Lungs Extra Strength - if you check it out you will find that it contains a number of wonderful herbs for the lungs.

Speaking of mullein, Luella May just wrote a great article about it.  Check it out:

Mullein is an herbal wonder for respiratory problems and much more

We have some mullein extract on order, but thus far have used the dried leaves to roll up and smoke as well as make into an herbal tea.  Though it may seem counter-intuitive to smoke anything when you are congested to the point of hardly being able to breathe, you would not believe how fast it opens up the airways.