Measles among adults, United States, 1985-1995

Objective: To report the incidence and characteristics of adult measles cas es in the United States and address the adequacy of current vaccination pol icies to eliminate measles transmission. Methods: Confirmed measles cases reported to the Centers for Disease Contro l and Prevention (CDC) from 1985 through 1995 were reviewed. Demographic da ta, exposure setting, and vaccination status of cases were analyzed and inc idence rates calculated based on U.S. census data. Main Outcome Measures: Age-specific incidence rates of measles and exposure setting. Results: Of the 75,204 reported measles cases of known age, 16,006 (21.3%) occurred in adults (persons > 19 years of age). The incidence in persons < 19 years of age (7.8/100,000) was 9.6 times that of all adults. Of 11,520 a dult measles cases for whom vaccination status was reported, 8,055 (69.9%) indicated no prior receipt of measles vaccine. Exposure setting tvas unknow n for the majority of adult measles cases (8,475, 52.9%); most frequently r eported were college or school (2840, 17.7%), home (1443, 9.0%), or a medic al setting (1286, 8.0%). International travel was associated with 289 (1.8% ) adult cases. From 1993 to 1995, incidence rates in all age groups were at record low levels, with adults contributing 29.5% (467/1584) of reported c ases. Conclusion: Although adults accounted for a steadily increasing proportion of measles cases during the study period, incidence rates in all age groups have decreased. Most adults who had measles were susceptible because of la ck of vaccination rather than vaccine failure. This analysis supports curre nt strategies to ensure the immunity of school/college-aged populations, an d health care workers.