The World Health Organisation has confirmed the H1N1 outbreak is now in the post-pandemic period, effectively declaring the alert over.

However, the virus has not disappeared.

Based on experience with past pandemics, the WHO now expects the H1N1 virus to take on the behaviour of a seasonal influenza virus and continue to circulate for “some years”.

New Zealand and India are presently experiencing outbreaks of the virus.

These countries were praised for their “vigilance, quick detection and treatment” in containing the virus.

“Globally, the levels and patterns of H1N1 transmission now being seen differ significantly from what was observed during the pandemic,” said WHO director-general, Dr Margaret Chan.

“Out-of-season outbreaks are no longer being reported in either the northern or southern hemisphere. Influenza outbreaks, including those primarily caused by the H1N1 virus, show an intensity similar to that seen during seasonal epidemics.”

H1N1

The H1N1 virus – or swine flu – was first recorded in Veracruz, Mexico during April 2009, before spreading across North America, Europe and south-east Asia in the following months.

The World Health Organisation incrementally increased its Pandemic Alert Level during 2009, eventually reaching the highest level - Phase 6 – and branding the spread of the H1N1 virus a “pandemic” on June 11th.

The WHO response has come under scrutiny, with accusations it caused panic from some quarters.

WHO officials have denied the accusations, criticising media portrayal of its pandemic warning system.

A note of warning was also sounded with regard to the continued impact of the virus.

“Based on available evidence and experience from past pandemics, it is likely that the virus will continue to cause serious disease in younger age groups, at least in the immediate post-pandemic period,” added Dr Chan.

“Groups identified during the pandemic as at higher risk of severe or fatal illness will probably remain at heightened risk, though hopefully the number of such cases will diminish.”