WHO declares first 21st century flu pandemic

The World Health Organization declared the first flu pandemic of the 21st century on Thursday, Sweden's health ministry said.

The health ministry said the United Nations agency was raising its pandemic flu alert to the top phase 6 on a six-point scale, indicating the first influenza pandemic since 1968 is under way.

"Today... the Minister for Elderly Care and Public Health Maria Larsson has called a press conference following a decision by the WHO to raise the pandemic level to six for the influenza A H1N1 virus," the ministry said in a statement.

The move will trigger heightened health measures in the WHO's 193 member states as authorities brace for the worldwide spread of the virus that has so far caused mainly mild illness.

'Moderate event for time being'

The move to phase 6 reflects the fact that the disease, widely known as swine flu, was spreading geographically, but not necessarily indicate how virulent it is.

"Phase 6, if we call a phase 6, doesn't mean anything concerning severity, it is concerning geographic spread ... Pandemic means global, but it doesn't have any connotation of severity or mildness," WHO spokesman Gregory Hartl said.

"In fact, what we are seeing with this virus so far is overwhelmingly to date mild disease. So we would think that this event is really a moderate event for the time being, because the numbers are high but the disease is overwhelmingly mild," he told Reuters Television before the committee meeting.

'Disease to be watched closely'

David Heymann, a former top WHO official now chairing Britain's Health Protection Agency, said that countries had tried to contain the virus through measures including school closures during the previous phase 5. This has extended the precious time needed to prepare for a full-blown pandemic.

"During phase 5, the government and people in the UK have had the time to prepare for a pandemic - this has hopefully decreased any surprise and concern that might be associated with a WHO announcement of phase 6, if one is made," he told Reuters.

As it spreads in humans, science cannot predict what course the virus will take, the disease it causes and the age groups infected, Heymann said. "The severity of that disease, the effectiveness of antiviral drugs and the stability of the virus must all be watched closely," he added.