P-643. Incidence and Clinical Characteristics of Invasive Group A Streptococcal Infections in Underhoused Adults in Toronto, Canada
Bibliographic record
Abstract
Abstract Background Post-pandemic increases of invasive group A streptococcal disease (iGAS) have been reported in many areas of the world; increased risk associated with illicit intravenous (IV) drug use has also been identified. Methods Since 1995, the Toronto Invasive Bacterial Diseases Network (TIBDN) has conducted prospective, population-based surveillance for iGAS in residents of Toronto/Peel Region (pop, 4.5M) in Canada. Homeless adults admitted to hospitals in the surveillance area are counted as residents. General and homeless population estimates were taken from Statistics Canada and published literature (doi:10.1136/bmjopen-2019-030221). Canada's National Microbiology Laboratory performs emm typing. Results In 2022/23, 88 iGAS cases (14% of all iGAS cases, 17% of adult iGAS) occurred in homeless persons; all were adults. Estimated iGAS incidence in homeless adults was 210/100,000/yr, versus 5.4/100,000/yr in other adults. Homeless persons with iGAS were younger than other adults (median age 47 v. 59 yr, P< .001); 70% were male (v. 63% in other adults, P=0.2). Homeless adults were more likely than other adults to be smokers (53% v. 27%, P< .001), to use IV drugs (46% v. 10%, P< .001), to have non-intact skin (43% v. 27%, P< .001) and to report recent soft tissue trauma (27% v. 17 %, P< .001). Compared to other adults, homeless adults were more likely to have comorbidities (90% v. 79%, P< .001), but less likely to be immunocompromised (3% v. 19%, P< .001). Presentations differed in homeless versus other adults (Table 1). 16 (18%) homeless adults required ICU admission, 10 (11%) mechanical ventilation, and 5 (8.5%) died. After age adjustment, outcomes did not differ between homeless and other adults. The median hospital length of stay was 8.5 days (IQR: 4-22) for homeless adults, and 8 days (IQR: 5-18) for other adults (P=0.7). The distribution of emm types of isolates in homeless and other adults is shown in Figure 1. iGAS in homeless adults was less likely to be caused by isolates of emm 1 and 12, and more likely to be caused by isolates of emm 49 and 74. Conclusion Homeless persons are at very high risk of iGAS, with IV drug use and skin integrity issues contributing. Outcomes of iGAS are similar to other adults. Differences in the emm types of isolates may be relevant to future vaccine program planning. Disclosures Allison McGeer, MD, AstraZeneca: Honoraria|GSK: Honoraria|Merck: Honoraria|Moderna: Honoraria|Novavax: Honoraria|Pfizer: Grant/Research Support|Pfizer: Honoraria|Roche: Honoraria|Seqirus: Grant/Research Support|Seqirus: Honoraria
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.003 |
| 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) | 0.004 | 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".