Oral fluid testing during 10 years of rubella elimination, england and wales

Abstract

Surveillance of rubella in England and Wales has included immunoglobulin M testing of oral (crevicular) fl uid from reported case-patients since 1994. The need for laboratory confi rmation to monitor rubella elimination is emphasized by poor sensitivity (51%, 95% confi dence interval 48.9%-54.0%) and specifi city (55%, 95% confi dence interval 53.7%-55.6%) of the clinical case defi nition. During 1999-2008, oral fl uid from 11,709 (84%) of 13,952 reported case-patients was tested; 143 (1.0%) cases were confi rmed and 11,566 (99%) were discarded (annual investigation and discard rate of clinically suspected rubella cases was 2,208/100,000 population). Incidence of confi rmed rubella increased from 0.50 to 0.77/1 million population when oral fl uid testing was included. Oral fl uid tests confi rmed that cases were more likely to be in older, unvaccinated men. Testing of oral fl uid has improved ascertainment of confi rmed rubella in children and men and provided additional information for assessing UK progress toward the World Health Organization elimination goal.