Current Lessons from 20th Century Serosurveillance Data on Rubella

Received 3 May 2001; electronically published 20 September 2001. Reprints or correspondence: Dr. Louis Z. Cooper (Lzcooper @compuserve.com). Clinical Infectious Diseases 2001; 33:1287 2001 by the Infectious Diseases Society of America. All rights reserved. 1058-4838/2001/3308-0002$03.00 By using serum specimens from the third National Health and Nutrition Examination Survey, Dykewicz et al. [1], from the Centers for Disease Control and Prevention (Atlanta), have offered a clear picture of the epidemiology of rubella seropositivity in the United States during the period of 1988–1994. These data reflect the interaction between the immunization program in the United States and the natural history of rubella. Antibody rates were highest among children 6–11 years old and in persons 140 years old (92% and 93%, respectively). The lowest rate of rubella seropositivity (78%) was found among persons born during the period of 1970–1974. As a reference point, rubella vaccine was licensed in 1969, and measles-mumps-rubella vaccine was licensed in 1971. I found several valuable lessons in this report. First, too many women of child-bearing age in the United States remain unprotected from rubella, even though reported cases of rubella and congenital rubella reached all-time lows in 2000. Until international immunization efforts, which are now underway, reduce the risk of importation of rubella from infected travelers, all settings (including emergency departments) where women seek health services must be alert to the women’s immunization needs. Two factors compound this hazard: (1) in many urban areas, high rates of immigration have brought into the country young women from countries where rubella immunization is not routine, and (2) young adults have the lowest coverage rates for health insurance in the United States. High immunization rates among children only reduce the rubella risk for seronegative women; they do not eliminate that risk. Second, the lowest seropositivity rates among the 1970–1974 birth cohort are reminders of the following: