Did you read the abstract or the whole thing, as much as i agree with the study, you cannot simply take the abstract and use it for your case. You need to look at methods, results etc. As they can really write whatever they want in the abstract.
Also, don't take massive doses of vitamin c, like said above, it does nothing, except for the 0.1% of the population who are vitamin c deficient. Same with echinacea (SP?), garlic (unless in laboratory conditions and a purified extract in an agar plate) etc.