Swine-origin influenza virus A(H1N1)v: lessons learnt from the early phase of the epidemic
Bibliographic record
Abstract
In late March 2009, Mexican authorities identified an unexpected increase in the number of cases of influenza-like illness (ILI), including a higher than expected number of cases of severe pneumonia characterized by respiratory distress syndrome.1 At the beginning of April, a novel influenza virus A/(H1N1) variant (H1N1v) of apparent swine origin was identified by the US Centers for Disease Control and Prevention in two children in California.2 The same variant was then identified in Canada in biological samples from a Mexican patient with ILI. The evidence of sustained community transmission of H1N1v in different countries on more than one continent led the World Health Organization (WHO) to declare Phase 6 of pandemic alert (‘The Pandemic Phase’). H1N1v appears to have derived from a further reassortment of a triple reassortant North American swine virus with the NA and M segments of a European swine virus.3 However, when and where this variant emerged remain unknown, though phylogenetic analyses suggest that it had been circulating for a number of years before trans-species passage and adaptation to the human host.4 H1N1v is efficiently transmitted among humans, probably through the same modalities as seasonal influenza viruses, that is, through large droplets or contact with contaminated surfaces. Moreover, because the variant is novel, much of the population is susceptible, increasing the potential for spread. Since the time of the identification of H1N1v, several lessons have been learned, though there are also some gaps in …
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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 | 0.003 | 0.011 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.003 |
| Scholarly communication | 0.003 | 0.007 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.004 | 0.008 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".