Apocalypse Not: Behind the Swine Flu Hysteria

At the height of the swine flu pandemic this spring, when the US Centers for Disease Control and Prevention was recommending that schools with cases of H1N1 be closed for 14 days and Mexico was still on lockdown, the epidemiology community already suspected the world wasn't ending. Why? The numbers came in: case fatality rate (how many infected people are dying) and replication rate (how many others an infected person will transmit the illness to — "R-zero," in disease-speak). H1N1 had an RØ of about 1.3, high enough to spread the virus but low enough that a strong isolation program could break its back. Its case fatality rate was a wussy 1.9 percent in Mexico and 0.1 percent worldwide. By comparison, the 1918 Spanish flu had an RØ of 2.7 and a case fatality rate of up to 5 percent, making it far more deadly. A real apocalypse, like the killer flu in The Stand — Stephen King's opus of epidemiologic eschatology — would be off the chart, with an RØ of 5 to 6 and a case fatality rate of 99 percent. So, don't panic ... unless H1N1 surges this fall. Where did we leave that hand sanitizer, again?