Sunday, August 30, 2009

Incidence of Death

Although it is natural to focus on the case fatality rate when considering the risk of a new virus like pandemic H1N1, comparing countries with this metric has become increasingly difficult given the variations in testing procedures. Some countries continue to publicise new cases of infection, some do not.

Although most countries report deaths, the absolute number of deaths is less informative than the numbers of death adjusted for population. One way to compare the effect of the new H1N1 virus on different countries is to calculate the number of deaths per 100,000 people.

Here is the list of the top 20 countries and the incidence of death per 100,000 people:

  1. Saint Kitts and Nevis – 1.9
  2. Cayman Islands – 1.8
  3. Argentina – 1.2
  4. Samoa – 1.1
  5. Tonga – 1.0
  6. Uruguay – 1.0
  7. Chile – 0.8
  8. Costa Rica – 0.7
  9. Australia – 0.7
  10. Paraguay – 0.6
  11. New Zealand – 0.4
  12. Mauritius – 0.4
  13. Brazil – 0.3
  14. El Salvador – 0.3
  15. Peru – 0.3
  16. Singapore – 0.3
  17. Malaysia – 0.3
  18. Ecuador – 0.3
  19. Brunei – 0.2
  20. Malta – 0.2

With the exception of Malta, all the top 20 countries are either in tropical islands, Central America or the Southern Hemisphere.

The absence of the United States, Canada and the UK from this list supports the idea that weather is a significant variable in incidence of death from the pandemic virus. Countries in their winter and in the tropics are clearly being hit harder than countries experiencing summer.

Although much has been made of the fact that there have been many more cases in Argentina than in Chile, when countries are compared on the basis of incidence of death per 100,000, the difference between Australia and New Zealand is nearly as great.

A number of countries are much lower on the list than one would expect based on the incidence of death in neighboring countries. For example, Malaysia reports an incidence of death per 100,000 of 0.3, while Indonesia’s number is 0.003, a 100 fold difference. Singapore reports an incidence of death per 100,000 of 0.3 while China reports 0.0003, a 1000 fold difference. These numbers strain credibility and suggest that Indonesia and China are not reporting many of their deaths.

We are just in the early months of what is likely to be a multi-year pandemic. The numbers reported here will likely increase dramatically in the coming months. What will be the final incidence of death?

That will depend in large part on what we do.

[Via http://monotreme1000.wordpress.com]

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