stylistic:style_transfer, structural:expansion
Communicable diseases

In 2007, the WHO organized work on pandemic influenza vaccine development through clinical trials in collaboration with many experts and health officials. A pandemic involving the H1N1 influenza virus was declared by the then director-general Margaret Chan in April 2009. Margret Chan declared in 2010 that the H1N1 has moved into the post-pandemic period. By the post-pandemic period, critics claimed the WHO had exaggerated the danger, spreading "fear and confusion" rather than "immediate information". Industry experts countered that the 2009 pandemic had led to "unprecedented collaboration between global health authorities, scientists and manufacturers, resulting in the most comprehensive pandemic response ever undertaken, with a number of vaccines approved for use three months after the pandemic declaration. This response was only possible because of the extensive preparations undertaken during the last decade".