The World Health Organization (WHO) tallied over 525,000 H1N1 cases and about 6,750 deaths worldwide.
Four H1N1 related deaths have been reported among pilgrims for the 40 countries, the WHO reiterated the safety of the H1N1 vaccine, adding that investigation into 40 post-vaccine deaths (among the over 65 million doses given in 16 countries alone) has found no association between the vaccine and the documented fatalities.
Norwegian scientists announced detection of a mutated H1N1 virus that may allow infection deeper into the airways leading to more severe disease. Hong Kong then reported the same mutation, and Finland saw it in July. The WHO subsequently stated that a similar mutation had been observed in six other countries as early as April. Despite the mutations, the H1N1 vaccine is still effective.
A single batch of H1N1 vaccine in Canada has been pulled after a higher than usual rate of severe allergic reactions.
CDC has confirmed a rare second H1N1 infection in the same individual in West Virginia.
In a study of US Army personnel, those who received the 2008 seasonal flu vaccine were 45% less likely to contract H1N1 and 62% less likely to be hospitalized if infected.