[2007 measles outbreaks among Tokyo youths: analysis of data on serum IgM antibody detection at a commercial diagnostic laboratory].

We analyzed data on measles-specific serum IgM detection at a commercial diagnostic laboratory in outbreaks among youths in the greater Tokyo area in 2007. Trends in monthly numbers of IgM antibody-positive specimens from persons aged > or =15 or <15 years from January 2000 to June 2007 corresponded well to weekly numbers of adult or pediatric patients per sentinel hospital or clinic as reported by the National Epidemiological Surveillance of Infectious Diseases (NESID). In 2007, the number of IgM-positive specimens greatly increased, mainly peaking at ages 0-1 and 18-30 years. The largest number occurred at 18 years, and the number of IgM-positive specimens in the > or =15 years group was 41% larger among males than females. The proportion of IgM-positive specimens among hospitalized patients was 22% in the >15 years or = group and 11% in the < 15 years group.