Flight CA112 took off from Hong Kong that day carrying 120 people, including a feverish man with a worsening cough. By the time it landed in Beijing, three hours later, twenty-two other passengers and two crewmembers had received infectious doses of the coughing man’s germs. From them it spread through more than seventy hospitals just in Beijing—yes, seventy—infecting almost four hundred health-care workers as well as other patients and their visitors.
