Domestic impact of tuberculosis screening among new immigrants to Ontario, Canada
Bibliographic record
Abstract
BACKGROUND: All Canadian immigrants undergo screening for tuberculosis (TB) before immigration, and selected immigrants must undergo postimmigration surveillance for the disease. We sought to quantify the domestic health impact of screening for TB in all new immigrants and to identify mechanisms to enhance effectiveness and efficiency of this screening. METHODS: We linked preimmigration medical examination records from 944,375 immigrants who settled in Ontario between 2002 and 2011 to active TB reporting data in Ontario between 2002 and 2011. Using a retrospective cohort study design, we measured birth country-specific rates of active TB detected through preimmigration screening and postimmigration surveillance. We then quantified the proportion of active TB cases among residents of Ontario born abroad that were detected through postimmigration surveillance. Using Cox regression, we identified independent predictors of active TB postimmigration. RESULTS: Immigrants from 6 countries accounted for 87.3% of active TB cases detected through preimmigration screening, and 10 countries accounted for 80.4% of cases detected through postimmigration surveillance. Immigrants from countries with a TB (all-sites) incidence rate of less than 30 cases per 100 000 persons resulted in pre- and postimmigration detection of 2.4 and 0.9 cases per 100 000 immigrants, respectively. Postimmigration surveillance detected 2.6% of active TB cases in Ontario residents born abroad, and TB was detected a median of 18 days earlier in those undergoing surveillance than in those who were not referred to surveillance or who did not comply. Predictors of active TB postimmigration included radiographic markers of old TB, birth country, immigration category, location of application for residency, immune status and age. INTERPRETATION: Universal screening for TB in new immigrants has a modest impact on the domestic burden of active TB and is highly inefficient. Focusing preimmigration screening in countries with high incidence rates and revising criteria for postimmigration surveillance could increase the effectiveness and efficiency of screening.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".