As global health workers keep close tabs on the avian influenza outbreak
in southeast Asia, their counterparts in the laboratory are concocting vaccines
for a worst-case scenario—the spread of a pandemic strain, unseen since
the 1918 scourge that claimed at least 20 million lives.
While the number of human cases of H5N1 influenza in Vietnam and Thailand
remains small—32 at press time—epidemiologists stay awake nights
shuddering over the nearly 70% mortality rate. In contrast, the annual influenza
(both type A and type B) epidemic that hits North America each winter kills
about 1% of those it infects.
Vastag B. Agencies Prepare Worst-Case Flu Vaccine. JAMA. 2004;291(12):1429-1430. doi:10.1001/jama.291.12.1429