Effectiveness of the Immigration Medical Surveillance Program for tuberculosis in Ontario.

Citizenship and Immigration Canada (CIC) screens immigrants for TB and permits those with inactive pulmonary TB to enter Canada conditionally, subject to medical surveillance; we studied this program in Ontario.This was an administrative database study with linkage of national and provincial data.In 1994-95, 1,341 cases of foreign-born active TB were diagnosed and a CIC record was found for 1,095. 149 (14%) were classified for surveillance and 142 were included in the analysis. A significant proportion (39/142: 27%) were diagnosed either before or as a result of immigration screening in Canada. These persons had arrived as visitors or refugees and were excluded from further analysis. Only 21 of the remaining 103 persons (20%) with immigration screening before the diagnosis of TB adhered to surveillance. Only 1 of 16 (6%) eligible persons was given therapy to prevent future episodes of active TB. Most presented with symptoms (82/103:82%) suggesting potential for TB transmission in Ontario.The current TB surveillance system for high-risk immigrants to Ontario is not effective in identifying and treating latent infection, and thus not effective in preventing future cases.