 The pandemic began to taper off in November 2009 , and by May 2010 , the number of cases was in steep decline . On 10 August 2010 , the Director @-@ General of the WHO , Margaret Chan , announced the end of the H1N1 pandemic , and announced that the H1N1 influenza event has moved into the post @-@ pandemic period . According to the latest WHO statistics ( as of July 2010 ) , the virus has killed more than 18 @,@ 000 people since it appeared in April 2009 , however they state that the total mortality ( including deaths unconfirmed or unreported ) from the H1N1 strain is " unquestionably higher " . Critics claimed the WHO had exaggerated the danger , spreading " fear and confusion " rather than " immediate information " . The WHO began an investigation to determine whether it had " frightened people unnecessarily " . A flu follow @-@ up study done in September 2010 , found that " the risk of most serious complications was not elevated in adults or children . " In an 5 August 2011 PLoS ONE article , researchers estimated that the 2009 H1N1 global infection rate was 11 % to 21 % , lower than what was previously expected . However , by 2012 , research showed that as many as 579 @,@ 000 people could have been killed by the disease , as only those fatalities confirmed by laboratory testing were included in the original number , and meant that many of those without access to health facilities went uncounted . The majority of these deaths occurred in Africa and Southeast Asia . Experts , including the WHO , have agreed that an estimated 284 @,@ 500 people were killed by the disease , much higher than the initial death toll . 
