Thursday, May 7, 2009

WHO considers flu alert overhaul

The World Health Organisation is considering an overhaul of its pandemic ratings system amid growing criticism that it provoked unnecessary 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 move comes against a backdrop of intensifying attacks on the WHO, which has been accused of "crying wolf" over its decisions to raise its pandemic alert from level three to an unprecedented five. This comes amid indications it may even go to the maximum level six.

Media organisations initially seized on the raising of the alerts in front page headlines around the world, but as it has emerged that the death toll has stayed relatively low, so the criticism has mounted. As of Thursday 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 between humans around the world, the WHO's system of pandemic alerts provides no indication of the danger of the virus.

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

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

In an interview with the FT 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," she said.

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

Only two weeks after the Mexican virus was first decoded, health officials are still struggling to understand which age groups and what overall proportion of a population are infected by the flu, and how many are at risk of dying or becoming seriously ill as a result.

With such limited data, they still want to be able to alert health authorities around the world to the potential risks so that they can step up their response while gathering more information.

Scientists also warn that even if outside Mexico the virus has so far proved relatively mild, there is a significant danger that it could mutate on mixing with some of the seasonal flu viruses now starting to circulate in the southern hemisphere. These are widely resistant to antiviral treatments such as Tamiflu.

The "Armageddon" scenario is that it might mix with the H5N1 bird flu virus, which is highly lethal in humans but so far has not proved to be easily transmitted between humans.

The WHO had already sparked concerns from a number of health authorities for changing its pandemic alert scale last month, just after the Mexican virus was identified. This had the effect of speeding up the escalation from level 3 and was out of step with many national pandemic plans.

Anthony Kessel, from the UK's Health Protection Agency, said the current arrangements were "a necessary alert system" but added: "It will be important for the WHO's member states and advisory bodies to determine whether in the future a link with the severity of the infection is feasible, and whether it would add value to our current system."

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