The Big Question: How Dangerous Is It?
As the total number of worldwide cases approaches 1,000 it seems at first glance that the H1N1 influenza virus may prove more lethal than seasonal influenza. To date, of the 985 confirmed cases, there have been 26 deaths (so a mortality rate of about 1/40 infections). Seasonal influenza kills between 1/1,000 (in age > 65) and 1/200,000 (age < 50). The difficulty with comparing these mortality rates is that there are likely a large number of H1N1 infections that have not been diagnosed (some estimate that about 1% have been). That would make the mortality rate about 1/4,000.
About 90% of deaths due to seasonal influenza occur in individuals age 65 or older. We don’t yet know whether this is true for H1N1.
The reason for the aggressive response to this virus is that there is still much we do not know. And, other animal influenza viruses have been much more dangerous. For example, the H5N1 avian influenza: First identified in Italy in 1878, highly pathogenic avian influenza is characterized by sudden onset of severe disease, rapid contagion, and a mortality rate that can approach 100% within 48 hours. The virus not only affects the respiratory tract but also invades multiple organs and tissues. The resulting massive internal haemorrhaging has earned it the lay name of “chicken Ebola”.
