I dont know what studies you are refering to but the very few robust good studies showechinacea has no affects
What is Expertise?
Expertise points are tabulated based on community ratings. An upvote on a question or answer earns 10 expertise points for the contributor. A downvote results in a loss of 2 points. Community rights can be earned as expertise points are accrued.
What are Contributions?
Contributions are based on updates made to articles, questions asked and answered, and comments.