In September 2009, news stories reported that researchers in Canada had found an increased risk of pandemic H1N1 (pH1N1) influenza in people who had previously been vaccinated against seasonal influenza.
In a school outbreak of pH1N1 in spring 2009, people with cough and fever were found to have received prior seasonal flu vaccination more often than those without.
Several public health agencies in Canada therefore undertook four additional studies during the summer of 2009 to investigate further. Taken together, the four studies included approximately 2,700 people with and without pH1N1.
The first of the studies found the seasonal vaccine to be associated with an increased risk of approximately 68 percent for pH1N1 disease.
The further 3 studies similarly found between 1.4 and 1.5 times increased likelihood of pH1N1 illness in people who had received the seasonal vaccine compared to those who had not.
WHO Finally Admits They Screwed up on Swine Flu
In related news, the World Health Organization (WHO) has admitted that it made mistakes in its response to H1N1 swine flu.
WHO influenza expert Keiji Fukuda conceded that the six-phase system for declaring a pandemic was confusing, and resulted in widespread panic about an illness which proved to be even less deadly than the similarly overhyped bird flu.
Critics have pointed out WHO's links to the pharmaceutical industry. Many drug companies made huge profits when governments bought enormous stockpiles of H1N1 vaccine, much of which has gone unused.