WHO raises flu pandemic alert level

The World Health Organisation this evening raised the global flu alert level to 5, the second highest phase that indicates "a pandemic is imminent".

"I have decided to raise the level of influenza pandemic alert from phase 4 to phase 5," WHO Director-General Margaret Chan told a news briefing about the swine flu outbreak that has killed as many as 159 people in Mexico and spread to the United States, Canada, Europe, Israel, and New Zealand.

According to the WHO's pandemic flu response guidelines, a Phase 5 alert is called when there is sustained human-to-human spread of the virus in at least two countries in one region.

"While most countries will not be affected at this stage, the declaration of Phase 5 is a strong signal that a pandemic is imminent and that the time to finalise the organisation, communication and implementation of the planned mitigation measures is short," the document reads.

Chan's move followed intensive consultations with experts and analysis of the spreading virus within and from Mexico.

The change in level puts governments on alert about the need to stockpile antiviral drugs such as Roche Holding's Tamiflu and GlaxoSmithKline's Relenza, and accelerates pharmaceutical industry efforts to create a vaccine to fight the swine flu strain.

The higher alert also signals the virus is unlikely to fade away, and could pose a prolonged public health threat.

"It is something here to stay. Now the question is at what level it will be circulating and how easily it is transmitted," one public health expert said.

On Monday evening, Chan convened a meeting of the WHO's emergency committee to assess the pandemic alert level which had previously been at 3 on the six-stage scale.

That panel recommended an increase to 4, which formally indicated that the infection could spread between humans to cause "community-level outbreaks".

Earlier today, WHO acting assistant director-general Keiji Fukuda told journalists on a teleconference that swine flu had been shown to infect people who had not been to Mexico, and the outbreak showed no signs of slowing.