WHO may redefine pandemic alert phases

May 26, 2009 (CIDRAP News) – In response to concerns from various governments about the possible effects of declaring a full-scale influenza pandemic, the World Health Organization (WHO) will call on outside experts to consider whether to revise the agency's definitions of pandemic alert phases, a WHO official announced today.

The spread of the novel H1N1 flu virus in Mexico, the United States, and Canada prompted the WHO to raise its pandemic alert from phase 4 to phase 5 on Apr 29. Despite signs of possible community-level transmission in other parts of the world, such as Japan and Spain, the WHO has not raised the alert to phase 6, defined as sustained community transmission in more than one global region.

At the WHO's annual meeting last week, several countries, concerned about potentially causing undue alarm, urged the WHO to go slow on moving to phase 6. Noting that most H1N1 cases have been mild, they argued that the pandemic phases should reflect not only the geographic extent of the disease, but also its severity.

Today Dr. Keiji Fukuda, the WHO's assistant director-general for health security and the environment, said the agency would call on scientists and public health experts to consider whether to change the phase definitions.

"What we're currently doing at WHO is trying to take a look at the interventions and see what kind of adjustments might be made to make sure the definitions really meet the situation," Fukuda said at a news teleconference. "To do this, we will be asking scientists and public health people who really have a good perspective on the issues to help us think this through."

He said he hopes this can be accomplished within the next few weeks.

Fukuda said the reasons for the WHO's decision include not only the concerns expressed at the World Health Assembly last week, but also an earlier request from southeast Asian countries at the ASEAN meeting. Officials at that meeting asked the WHO to consider whether the criteria for moving to phase 6 should be adjusted.

He commented that the alert phases were developed a tools to help governments prepare for a pandemic. The phases, he added, were fashioned "in the shadow of avian influenza H5N1," which has caused rare but often lethal human cases, unlike the novel H1N1 virus, which usually causes mild illness.

"The spread of this virus has really highlighted the fact that this is a very different situation than with H5N1," he said.

The WHO is looking very carefully at two questions: what level of transmission "really indicates you have spread in the community" and whether and how to deal with the question of an outbreak's severity, Fukuda reported.

Echoing his comments at a May 22 news briefing, he argued that the most important issue is not the pandemic phase definitions but whether proper public health actions are being taken in response to the disease.

Reporters asked Fukuda why the WHO is so reluctant to go to phase 6, since it officially means only that the virus is spreading in more than one region and says nothing about its severity.

"I think the answer is really almost another question—the question of what is to be gained by going to another phase?" he replied. "When we went from phase 3 to phase 4 and from 4 to 5, there were real gains for countries by doing that, in terms of focusing attention, in terms of implementing actions, in terms of bringing in resources and really focusing everybody's attention on what had to be done."

He added that many countries are already responding appropriately to the epidemic, and that moving to phase 6 could cause unnecessary work and potentially lead to panic and cynicism.

"If we go to phase 6 without very clear evidence that there's a sort of change in the global situation, it can lead to extra work without much gain, it can lead to some level of panic, it can lead to some level of cynicism that something's being declared but is not usefully producing something of public health benefit or gain," he said.

He further observed that the pandemic phase definitions have evolved to become simpler in response to feedback that the earlier versions were too complicated. But now the WHO has found that they don't adequately capture the concerns of countries.

In response to a question, Fukuda said the move to reconsider the phase definitions doesn't necessarily mean the WHO won't declare a pandemic if the epidemiologic situation changes while those deliberations are under way.

"If in another country such as Japan or somewhere in Europe or in the southern hemisphere we begin to see activity that looks much like Mexico or in the US, very large outbreaks with large numbers of people, that in itself could well be enough to take us up to pandemic phase 6," he said.

When a reporter asked if the WHO move might engender cynicism because the agency will be seen as bowing to political pressure, Fukuda cited the swine flu episode of 1976, when the US government launched a nationwide immunization campaign in response to a feared pandemic that never materialized.

Asserting that the most important question is what actions should be taken to protect people, he said, "Perhaps the single biggest lesson from that [1976] episode is to take stock, take a look at what reality is teaching you, don't put yourself in a hole and leave yourself there."

Replying to another question, Fukuda said that even in an informal sense, apart from the official phases, it is premature to call the H1N1 situation a pandemic. He said the virus is clearly spreading but has not reached or taken root in all parts of the world.

"I think it's quite possible that it'll continue to spread and it will establish itself in many other countries and multiple regions, at which time I think it would be fair to call it a pandemic," he commented.

In other comments, Fukuda declined to predict when the WHO might make a recommendation on starting production of an H1N1 vaccine: "Giving some indication from WHO in terms of H1N1 vaccine production will be important sometime during the summer, but right now I don't think I can be much more specific than that."

See also:

May 22 CIDRAP News story "WHO sticks with current pandemic alert phase"

May 18 CIDRAP News story "WHO is urged to go slow on declaring pandemic"

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