Atypical measles syndrome: A continuing problem

Abstract

Atypical measles syndrome (AMS), first described in 1965 by Rauh and Schmidt, is characterized by high fever, unusual rash, and pneumonia, often with a history of immunization with killed measles vaccine. AMS is generally thought to be a hypersensitivity response to natural measles infection in individuals who have previously received killed measles vaccine, although several investigators have reported AMS-like illness in children who had been immunized only with live measles vaccine. These latter reports may be misleading since it is sometimes clinically difficult to distinguish typical from atypical measles. During a measles epidemic in 1974-1975 in Northern California, a number of physicians reported laboratory-confirmed measles in patients who had signs and symptoms compatible with AMS. We investigated these cases to clarify the epidemiology of AMS and its association with previous measles immunization. Two of the cases have been reported.