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Canada’s blanket immigration screening for TB inefficient, costly
Data in the Canadian Medical Association Journal reported that blanket tuberculosis screening procedures currently in place for all immigrants entering Canada are inefficient and should be focused on those arriving from countries in which the disease is greater.
“Each year, about 400,000 prospective immigrants to Canada undergo screening for active TB, of which about 250,000 settle in Canada,” the researchers wrote. “These preimmigration medical examinations, coupled with postimmigration surveillance of selected immigrants deemed to be at high-risk for the development of active TB, require the coordinated efforts of federal, provincial or territorial, and local health authorities, as well as medical providers and the immigrants themselves. Despite the complexity and cost of this screening program, its domestic impact on active TB in patients born abroad is poorly understood.”
Using information collected from Citizenship and Immigration Canada (CIC) data sets, researchers reviewed the medical examination records of 944,375 immigrants who settled in Ontario from 2002-2011. Resident subsets were created based on whether immigrants entered the country before or after 2008, when universal preimmigration screening was added to pre-existing postimmigration surveillance procedures. Active TB diagnoses detected through both methods were compared to determine pre- and postimmigration surveillance effectiveness. Birth country-specific rates of TB, along with predictors of active TB among new residents, also were examined.
There were 380 cases of active pulmonary TB detected among 357,085 preimmigration medical examinations conducted from 2008-2011 (incidence, 106.4 cases per 100,000). Among all examined medical records, postimmigration surveillance detected 502 cases of active TB developed within 2 years of residence (incidence, 53 cases per 100,000). New residents from only six countries made up 87.3% of TB cases detected by preimmigration screening, while 10 countries accounted for 80.4% of those detected by postimmigration screening. Cases of TB detected by postimmigration surveillance made up 2.6% of all TB cases reported among Ontario residents born abroad, and predictors of TB after immigration included CIC referral of postimmigration surveillance, incidence rate of TB in birth country, immigration category, location of application for residence, immune status and age.
The researchers said these findings provide evidence for new screening practices that focus on immigrants with higher risk of developing active TB.
“New immigrants arrived in Ontario from 214 countries during the study period, but all cases of active TB detected through preimmigration screen or postimmigration surveillance occurred in patients who originated from just 35 countries,” the researchers wrote. “Our findings highlight the inefficiency of universal screening for TB among new immigrants independent of the incidence of disease in their countries of origin.” – by Dave Muoio
Disclosure: The researchers report no relevant financial disclosures.