What is it that makes this virus unusual? and What have we learned from the SARS experience? One thought that turns up in the latter sort is that “humankind has had a lucky escape.” The scenario could have been very much worse. SARS in 2003 was an outbreak, not a global pandemic. Eight thousand cases are relatively few, for such an explosive infection; 774 people died, not 7 million. Several factors contributed to limiting the scope and the impact of the outbreak, of which humanity’s good luck was only one.