Margret Chan declared in 2010 that the H1N1 has moved into the post-pandemic period .
A pandemic involving the H1N1 influenza virus was declared by the then Director - General Margaret Chan in April 2009 .
Director - General   declared in 2010 that the H1N1 has moved into the post-pandemic period .
A pandemic involving the H1N1 influenza virus was declared by the then Director - General Margaret Chan in April 2009 .