Swine flu alerts prompt WHO rethink on pandemic rating

The World Health Organisation is considering an overhaul of its pandemic rating system amid criticism that it provoked alarm by rapidly escalating its warnings over swine flu.

Officials at the agency's headquarters in Geneva said they were discussing changes to the six-point scale to make clear in the future the gravity of the threat posed by a new virus.

The WHO has been accused of “crying wolf” over its decisions to raise its pandemic alert from level three to an unprecedented five. There are indications it may even go to six, the maximum level.

This raising of the alerts led to frontpage headlines around the world. But as the death toll remained relatively low, so the criticism mounted. As of yesterday morning the WHO had confirmed 2,099 cases in 23 countries, including 44 deaths.

While designed to identify and classify the spread of a new flu virus, the WHO's system of pandemic alerts provides no indication of the danger of a virus.

Even if the influenza type A (H1N1) virus in Mexico proves no more lethal than a typical seasonal flu, it could still trigger a level six pandemic alert if it is identified as spreading widely between humans in different parts of the world.

Margaret Chan, director-general of the WHO, has stressed that an increase to level six is a technical change that does not mean people around the world are at serious threat.

In an interview with the Financial Times earlier this week, Ms Chan defended the organisation's public statements. “I am not predicting the pandemic will blow up, but if I miss it and we don't prepare I fail. I'd rather over-prepare than not prepare.”

But her reassurances clash with a widely held public understanding of a pandemic as the spread of a serious infectious disease.