Monday, May 25, 2009

WHO to Overhaul Alert System

The WHO is to develop a new system for alerting the world to new diseases with the ability to cause pandemics. According to the deputy director-general, Kenji Fukuda, while the exact wording of the new rules cannot be predicted beforehand, the nature of the protocol will include a "substantial risk of harm to people." This will either be in addition to or instead of the principle determinant of the current rules, which is the geographic spread of the disease, even if the infection is relatively benign.

This overhaul is ostensibly in response to mounting international criticism over the implementation of the alert protocol during the swine flu outbreak. According to countries most affected by the the outbreak, such as Mexico, the six tier system in place currently does not account for the lethality of the pathogen. Thus, these countries complain that the system is prone to cause undue panic and substantial economic damage even though the disease is relatively benign. Furthermore, the guidelines for implementing the alert protocol is nebulous. For example, in April, when swine flu was first detected in North America, the alert level was raised from 4 to 5, while no commensurate action was taken as the virus was detected in Europe. This discrepancy is in apparent contradiction to the current guideline which uses the spread of contagion from one continent to another as the premise for raising the alert level. In response, Dr.Fukuda offers that while the presence of swine flu was detected in the latter case, there was no evidence of "community spread", which is technically the spirit of the guideline for raising the alert level.

While the case for changing the current system is convincing, there remains concerns over creating a new system which is too conservative and less sensitive to the rise of potentially devastating infectious diseases. In contrast to determining geographical spread, scientifically establishing lethality is a difficult process which requires a large sample size, meaning that the number of infected must be relatively high before a statistically significant rate can be determined. Thus, by the time the reliable metric for raising the alert is established, valuable time would have already been wasted.

This article raises an interesting question: what would be a good parameter for a global system of alert? My take on this is that perhaps it is the global part of the global system that is the problem. Any rational system of alert should be able to take into account that different regions are at different levels of risk for any particular pathogen. Blanket grades of "alertness" for the entire world or even for continents, with no regard for local, regional infrastructural, environmental, and behavioral patterns, has the inevitable tendency to both cause unnecessary panic in one area while simultaneously not doing enough to warn others.


Source: International Herald Tribune, May 25 2009, p.5.

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