Rubella outbreaks among Hispanics in North Carolina: lessons learned from a field investigation

To describe the epidemiology and the lessons learned from two simultaneous, but unrelated, outbreaks of rubella in North Carolina affecting mostly Hispanic immigrants of Mexican origin.

A case and contact investigation was conducted at industrial work sites and Hispanic communities between March 26 and June 15, 1996, using both structured and informal interviews. Active surveillance was conducted at hospitals, clinical laboratories, primary care physicians' offices, local health departments, and migrant health centers to identify additional cases. Rubella specific IgM testing was performed by the North Carolina State Laboratory to confirm cases. Vaccination clinics were conducted in communities and at work sites with a large Hispanic population in affected counties to reduce the number of susceptible persons.

Eighty-three confirmed cases of rubella were reported: 75 cases from the first outbreak and 8 from the second. The mean age of cases from both outbreaks was 24 and 20 years, respectively. Only three cases occurred among children under five years of age, two in the first outbreak and one in the second. Seventy-one (95%) cases in the first outbreak and all 8 cases in the second outbreak were Hispanics; 21 (28%) cases from the first and 3 (37%) from the second outbreak were females, and a total of 65 (78%) cases from both outbreaks were industrial workers. Six women with confirmed cases in the first outbreak were pregnant at the time of exposure. No females cases were pregnant in the second outbreak.

The outbreaks in North Carolina confirmed the persistent susceptibility to rubella in Hispanics and persons migrating from countries where the rubella vaccine is not used for routine childhood vaccination. The ultimate goal of rubella vaccination programs is to prevent fetal infection and congenital rubella syndrome (CRS). Thus, to eliminate rubella from the United States, efforts should focus on understanding new emerging patterns of disease transmission and vaccinating susceptible adults in settings where they congregate.