AN EPIDEMIOLOGIC INVESTIGATION OF A RUBELLA OUTBREAK AMONG THE AMISH OF NORTHEASTERN OHIO

From April 1990 to April 1991, 278 cases of rubella were reported to t he Ohio Department of Health. Of these, 276 (99 percent) were among th e Amish of northeastern Ohio. The outbreak involved eight counties in an area that contains large settlements of Old Order Amish. Members of this community of Amish frequently take religious exemption from reco mmended immunization practices and are believed to represent a high pr oportion of Ohio's rubella-susceptible persons. Vaccination history wa s known only for 146 of the Amish people. Of those, only four had a po sitive history of rubella vaccination. Of the 276 Amish with cases of rubella, 65 (24 percent) were younger than age 5 years, 104 (38 percen t) were ages 5-14, 46 (17 percent) were ages 15-19, 32 (12 percent) we re ages 20-29, 6 (2 percent) were ages 30 or older, and age was not re ported for 23 (8 percent). The ratio of males to females with rubella was 1:1. Five women of the Amish community were pregnant; four had bee n ill with symptoms consistent with rubella. Three were in their first trimester. Congenital rubella syndrome did not occur in any of the fo ur live births. Serology was available for only the two non-Amish peop le, and both were acute phase serum-positive for Immunoglobulin M.