BEIJING, Aug. 11 (Xinhua) -- The World Health Organization (WHO) officially declared the H1N1 flu pandemic over Tuesday, with Director-General Margaret Chan saying the new virus had "largely run its course."
The announcement came about 15 months after the WHO confirmed initial outbreaks of influenza H1N1 in Mexico and the United States on April 24, 2009, followed by concerted global efforts to fight the new virus that has spread to 214 countries and regions and led to at least 18,449 deaths.
Nevertheless, Chan warned the announcement did not mean the H1N1 virus had gone away, and that "localized outbreaks of different magnitude may show significant levels of H1N1 transmission."
The virus was first named human swine flu due to preliminary findings that it is genetically a reassortment of swine flu, human flu and avian influenza (bird flu). The name continued to be used in many countries although the WHO later changed its name to influenza H1N1 in April.
The flu pandemic turned out less severe than expected. In April last year, Chan declared "a public health emergency of international concern," highlighting that the virus was unpredictable.
The WHO raised its flu pandemic alert level twice in three days from April 27 and further raised it in June to phase six, the highest level of alert, meaning the virus had led to a flu pandemic.
By early November 2009, influenza H1N1 was the most common cause of human flu. The number of confirmed infections continued to increase, including over 10,000 deaths worldwide, prompting high alerts or emergency warnings in the United States, Mexico, Argentina and Mongolia.
- WHO declares end of H1N1 pandemic 2010-08-11