"Based on apparently the only double-blind placebo-controlled influenza vaccination and outcomes study conducted (in healthy children 6 to 15 years of age), which has been published in a peer-reviewed journal, it is clear that getting a flu shot greatly increases the risk (by 4-plus-fold) that a person who receives it will contract and potentially spread one or more non-influenza respiratory viruses, some of which are not serious and morbid infections in humans."
Dr. Paul King
http://cid.oxfordjournals.org/content/early/2012/03/13/cid.cis307
