Four new Canadian studies have found the traditional flu vaccine may have increased the risk of infection with swine flu by as much as 68 percent.
The studies published in PLoS Medicine did not show whether there is a true cause and effect between the traditional vaccine and subsequent swine flu illness, but researchers say this years flu vaccine will include the swine flu strain.
The strain should provide protection against H1N1 and eliminate any risk that may have been due to the 2009 seasonal vaccine.
It did not include protection against H1N1.
