An epidemic of Hong Kong (A2) influenza occurred in U.S. airmen at Korat, Thailand, after the infection was introduced by flight crews returning from other parts of Asia. The involved population consisted exclusively of healthy young adults living in an environmental situation that was not conducive to rapid or widespread dissemination of respiratory viruses. During a 3-month period, 8% of the population experienced an influenzalike disease severe enough to require relief from duty, while by conservative estimate, 12% actually became infected. All illnesses were brief and uncomplicated. Most of the men had received polyvalent influenza vaccine within the preceding 6 months; severity and duration of illness were apparently unmodified by either recent vaccination or by multiple prior vaccinations.
Present address: U.S. Air Force Academy, Colorado Springs, Colorado.
Alternate address: SEATO Medical Project, U.S. Component, APO San Francisco 96346.