Commentary
New H5N1 Pandemic Alert System Controls Panic
Recombinomics Commentary 21:10
June 21, 2008
WHO’s new system addresses such issues of interpretation with three layers. The first comprises phases 1 to 3 and is defined as “predominantly animal infections; limited transmissibility among people”.
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Phase 4 would be “sustained human-to-human transmission of animal or hybrid animal-human influenza virus, able to cause sustained community-level outbreaks that have been verified” — this is when health authorities can consider issues such as rapid containment, discussion of phase changes, and switching to a pandemic vaccine.
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Phases 5 and 6 would comprise the “geographical spread” of flu. There is also a post-pandemic phase.
The above description of the newly proposed pandemic alter levels is curious. The level of human to human (H2H) transmission rose dramatically in 2005 and has been at an increased level ever since, which would require WHO to raise the level to 4 under the old system. However, this would trigger vaccine distribution and implementation of a range of costly pandemic preparedness measures. However, the time between increased H2H transmission and sustained H2H transmission is uncertain. In the past WHO has spent much time and energy denying the increase in H2H, which creates significant credibility issues, since they have been in denial for more than 3 years now.
The denials relied on a rigorous lab confirmation, which was easily avoided by simply not testing index cases, and testing later cases after the start of Tamiflu treatment, which lowered RNA to levels below detection.
These avoidance methods have been on the increase lately, and include the most recent cases in Indonesia.
This approach was evident in one of the largest clusters recorded to date in Indonesia in Garut. Although only three cases were confirmed, each confirmed case was linked to another case that had died shortly before the confirmed case developed symptoms. Moreover, others linked to the confirmed cases developed symptoms and were hospitalized, but a Tamiflu blanket had been applied to the entire village so the subsequent cases recovered and tested negative.
This scenario is still ongoing in Indonesia. Of the five most recent confirmed cases, three are linked to cases which died just prior to disease onset in the confirmed case. In one of the clusters a sibling subsequently developed symptoms and was hospitalized, but recovered and tested negative for H5N1. Thus, for the five most recent official cases there are four associated cases, so of the nine most recent cases, seven were in clusters that involved H2H transmission.
The new system will allow WHO to acknowledge these clusters, which are conspicuously absent from the WHO updates, without an associated increase in alert levels.
The new system will also allow for panic control because when the transmission is sustained, which was the definition of a pandemic under the old system, the sustained transmission will just be at level four.
Levels five and six appear to be for panic control so the public can be reminded that when the pandemic begins there will still be two more levels left, which are linked to the spread of the sustained transmission, which will likely take a few weeks.
Thus, the new system acknowledges that the current level of H5N1 transmission is just one level from a pandemic, but the pandemic level will be called four instead of six, and not appear to be as dire, since the scale will have two additional levels remaining.
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