" If Fouchier’s pandemically engineered H5N1 had breached his laboratory, or if something similar emerges naturally, the resulting damage to civilization is hard to fathom. Even if H5N1 follows the Spanish Flu percentages—30 percent infected and a lethality of 2 percent—Fouchier’s superbug would kill 42 million people. However, Webster thinks that is a foolishly low estimate. Why would the lethality decrease when Fouchier just proved the virus can become airborne without weakening? Webster thinks 3.5 billion could die. "

― Richard A. Clarke , Warnings: Finding Cassandras to Stop Catastrophes