P1-S2.53 Hepatitis C Virus in men who have sex with men with no history of injection drug use - evidence for sexual transmission? A Canadian perspective
Bibliographic record
Abstract
Background Sexual transmission of hepatitis C virus (HCV) is not common compared to other modes of transmission such as injection drug use (IDU). There have been recent reports of sexually transmitted HCV outbreaks among men who have sex with men (MSM) in Europe. The present analysis examines the Canadian HCV seroprevalence in MSM with no reported history of IDU. Methods Data from Phase 1 of M-Track (2005−2007), a national enhanced surveillance system of HIV and other sexually transmitted and blood-borne infections (STBBI) and associated risk behaviours among MSM in Canada, were analysed. HCV and HIV status were ascertained using serology tests on dried blood spot (DBS) specimens, and risk factors were assessed via self-administered questionnaire. Bivariate analyses using χ2 tests and ORs with 95% CIs were performed. Results Overall (regardless of IDU history), 5.3% of M-Track participants were seropositive for HCV. Among MSM who did not report any history of IDU (N=3250), HCV seropositivity was 2.1%, and was higher among HIV-infected MSM compared to those who were uninfected (5.1% vs 1.7% respectively, p<0.001). Factors associated with HCV seropositivity among non-IDU are presented in Abstract P1-S2.53 table 1. Being 30 yearss of age or older, having ever received money, drugs, or goods for sex, and use of any recreational drug in the 2 h preceding or during sex (specifically heroin/opioids, marijuana, tranquilisers, or cocaine) were all positively associated with being seropositive for HCV. Asbtract P1-S2.53 Table 1 Self-reported factors associated with HCV seropositivity among MSM with no self-reported history of IDU, M-Track Phase 1 (2005−2007) Risk factor HCV positive N (%) Univariate OR (95% CI) p value Age (N=2167) 29 or less (Ref) 2 (0.4) 5.5 (1.3 to 22.8) 0.015 30 and up 38 (2.2) Number of male anal sex partners in past 6 months (N=1342) One (Ref) 5 (1.1) 1.5 (0.6 to 4.2) 0.408 Two or more 15 (1.7) HIV seroconcordant unprotected anal intercourse (“serosorting”) (N=2136) No (Ref) 30 (1.9) 0.6 (0.3 to 1.5) 0.266 Yes 6 (1.1) Ever received money, goods, or drugs for sex (N=2534) No (Ref) 30 (1.3) 8.2 (4.6 to 14.5) <0.001 Yes 21 (9.7) Ever used recreational drugs within 2 h of sex (N=2536) No (Ref)Yes 32 (1.6)17 (3.4) 2.2 (1.2 to 4.0) 0.008 Ever used heroin/opioids within 2 h of sex (N=2521) No (Ref) 42 (1.7) 8.5 (3.2 to 22.9) <0.001 Yes 5 (12.8) Ever used alcohol within 2 h of sex (N=2575) No (Ref) 14 (2.1) 0.9 (0.5 to 1.7) 0.729 Yes 35 (1.8) Ever used marijuana within 2 h of sex (N=2539) No (Ref) 19 (1.2) 2.8 (1.6 to 5.1) <0.001 Yes 31(3.3) Ever used tranquilisers within 2 h of sex (N=2518) No (Ref) 46 (1.9) 5.5 (1.6 to 18.7) 0.016 Yes 3 (9.4) Ever used cocaine within 2 h of sex (N=2520) No (Ref) 29 (1.4) 4.1 (2.3 to 7.3) <0.001 Yes 20 (5.3) Ever used sexual enhancers within 2 h of sex (N=2545) No (Ref) 29 (1.8) 1.1 (0.6 to 2.0) 0.671 Yes 19 (2.0) Conclusions These findings do not confirm sexual transmission of HCV given the possibility of unreported IDU or other unknown parenteral transmission risk factors in this sample; however, they do support existing evidence of increased risk of HCV infection among HIV-infected MSM. Interpretation of results is limited by the self-reported nature of behaviours and the inability of laboratory tests used to distinguish between current infection from resolved/treated HCV or acute from chronic HCV status. Furthermore, behaviours reported in the past 6 months may not accurately reflect the risk profile of HCV-seropositive individuals at the time of infection. HCV testing for HIV-infected MSM, even in the absence of an IDU history, may be of benefit.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".