On August 10, 2010, the World Health Organization (WHO) International Health Regulations (IHR) Emergency Committee and the WHO Director-General, Dr. Margaret Chan, declared an end to the 2009 H1N1 influenza pandemic. This declaration was based on strong indications that influenza, worldwide, is transitioning toward seasonal patterns of transmission.

In the majority of countries, out-of-season 2009 H1N1 outbreaks are no longer being observed, and the intensity of 2009 H1N1 influenza virus transmission is lower than that reported during 2009 and early 2010. Members of the Emergency Committee further noted that the 2009 H1N1 viruses will likely continue to circulate for some years to come, taking on the behavior of a seasonal influenza virus.

This does not mean that the H1N1 virus has disappeared. Rather, it means current influenza outbreaks including those primarily caused by the 2009 H1N1 virus, show an intensity similar to that seen during seasonal epidemics. Pandemics, like the viruses that cause them, are unpredictable. WHO noted that continued vigilance is extremely important, and it is likely that the virus will continue to cause serious disease in younger age groups and pregnant women, at least in the immediate post-pandemic period.