Fourteen (3%) of 495 Thai health care personnel were identified as having a serum sickness-like reaction in 2008 after receipt of inactivated influenza vaccine manufactured in Thailand. These health care personnel experienced fever, myalgia, centrifugal arthralgias, and injection site erythema. A history of allergic reactions to food or drugs (adjusted odds ratio, 5.9; 95% confidence interval, 1.54-25.4) was independently associated with a serum sickness-like reaction.