Lies, Damned Lies, and Statistics
One of the most worrisome numbers bandied around by the media has been the 50% mortality rate with Avian Flu. Out of roughly 160 persons confirmed to be infected, 80 have died. This one `fact’ has been repeated hundreds of times, and many have simply accepted it as the truth.
While it is possible that the Avian Flu could have a 50% death rate, it is by no means certain.
During the last great pandemic, the Spanish Flu of 1918, between 20,000,000 and 100,000,000 people died. Why the large disparity in numbers? We simply didn’t keep good records. At some point, even in the United States, exact numbers gave way to estimates.
Today, many experts use 40 million to 60 million fatalities worldwide. This translates to about a 5% mortality rate. Even at the highest estimate, we are around 10%.
Today, the world’s population is 4 times greater than it was in 1918, and our ability to spread the disease is greatly enhanced by air travel, which did not exist in 1918. A similar pandemic could kill between 100 million and 400 million people.
What we simply don’t know right now is how many people have actually contracted the avian flu. We know of 160 people who became ill enough to go to the hospital, and of those, half of them died. There could easily be hundreds, even thousands of `mild’ cases of avian flu that simply went unreported.
Until a seroprevalence study is undertaken, where thousands of people are tested for H5N1 antibodies, we simply don’t know if these mild cases exist or not. If they do, then Avian Flu may be far less deadly than currently thought.
As the major outbreaks have occurred in China and in Vietnam, the ability to do this sort of testing has been limited. Hopefully, it will be done in Turkey, but there are political forces at work that may hinder that attempt.
During the Spanish Flu outbreak in 1918, fewer than half the population actually caught the flu. Some people, for unknown reasons, even when exposed, did not catch the virus. With all flu outbreaks, this seems to hold true. Some of us have a natural immunity.
This is not to minimize the impact of an Avian Flu pandemic. Even a 5% fatality rate, assuming 1/3rd of the world’s population caught the virus, would result in 100 million deaths. In the United States, it would translate into 5 million fatalities.
It is important to realize that, historically, during a pandemic, half of the population never gets sick. And of those that do, 95% survive.
While there is no guarantee that next pandemic will follow suit, it is a far less dire outlook than the media now paints.
