West Nile Virus positivity amongst Canadian blood donors and effectiveness of off‐season screening
Bibliographic record
Abstract
BACKGROUND: We sought to examine the prevalence of West Nile Virus (WNV) nucleic acid test (NAT) positivity over time in Canadian blood donors, examine the level of false-positive NAT screening, and understand the effectiveness of travel-related testing outside of WNV seasonality in Canada. STUDY DESIGN AND METHODS: All blood donations in Canada (except Québec) between 2018 and 2023 were tested by the Roche Cobas WNV-NAT assay during the summer-fall season by Canadian Blood Services. Testing for recent travel outside Canada was performed in the winter-spring season. All 2023 WNV-NAT-positives were confirmed by two independent WNV-specific polymerase chain reaction (PCRs). RESULTS: While WNV positivity varied by location and time, no increasing trend of positivity was observed over the 6-year study period. No WNV-NAT-positive donors with a history of recent travel outside of Canada in the winter-spring season were identified by donor screening (2018-2023). In total, 2,454,102 samples were tested during summer months and 267,988 in winter months. In 2023, WNV-specific PCR confirmed 10 of 13 (76.9%) screening WNV-NATs. Recent Japanese Encephalitis Virus (JEV) vaccination was identified as a potential false positive for initial WNV screening results. DISCUSSION: Between 2018 and 2023, WNV-NAT positivity amongst Canadian blood donors remained stable, with no evidence of an increasing positivity trend. The utility of off-season travel-related testing may be limited, as no donors were identified during the six-year study timeframe. Finally, confirmation testing using WNV-specific PCR is recommended to identify true cases and to limit misidentification of other genetically similar viruses, such as JEV.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".