Bacillus Calmette-Guerin vaccination and multiple sclerosis: a population-based birth cohort study in Quebec, Canada

Background and purpose: The bacillus Calmette-Guerin (BCG) vaccine could reduce the incidence of multiple sclerosis (MS) through immunomodulation. Previous studies, presenting some limitations, reported no association. We re-examined this association in a large cohort focusing on relapsing-remitting MS (RRMS). Methods: The cohort included 400,563 individuals, and was linked with the Quebec provincial BCG vaccination registry and administrative health data. Individuals were followed up from 1983 to 2014 and then within Period 1 (1983-1996) and Period 2 (1997-2014), for the occurrence of MS. Incident MS cases were defined as those with ≥3 hospital or physician claims for MS. Subjects with ≥1 drug reimbursement for MS disease-modifying therapies were classified as RRMS. Cox proportional hazards regression was used to estimate hazard ratios (HRs) over the follow-ups, adjusting for potential confounders. Possible effect modification due to sex was assessed. Results: A total of 178,335 (46%) individuals were BCG vaccinated. There were 274 (0.06%) incident MS cases identified in 1983-1996, and 1433 (0.4%) in 1997-2014. No association was found with RRMS, either in Period 1 (adjusted HR [HRadj ] = 0.96, 95% confidence interval [CI] = 0.63-1.45; 96 cases) or in Period 2 (HRadj = 1.02, 95% CI = 0.85-1.23; 480 cases). The remaining MS cases, for whom the phenotype was unknown, were positively associated with BCG over the entire follow-up (HRadj = 1.25, 95% CI = 1.10-1.41; 1131 cases) and in Period 2 (HRadj = 1.33, 95% CI = 1.17-1.52; 953 cases). No interaction with sex was found. Conclusions: Findings suggest that BCG vaccination does not decrease the risk of RRMS, and that future studies should consider phenotypes of MS

Road traffic crashes and prescribed methadone and buprenorphine: A french registry-based case–control study

Background: Opioids have been shown to impair psychomotor and cognitive functioning in healthy volunteers with no history of opioid abuse. Few or no significant effects have been found in opioid-dependant patients in experimental or driving simulation studies. The risk of road traffic crash among patients under buprenorphine or methadone has not been subject to epidemiological investigation so far. The objective was to investigate the association between the risk of being responsible for a road traffic crash and the use of buprenorphine and methadone. Methods: Data from three French national databases were extracted and matched: the national health care insurance database, police reports, and the national police database of injurious crashes. Case-control analysis comparing responsible versus non responsible drivers was conducted. Results: 72,685 drivers identified by their national health care number, involved in an injurious crash in France over the July 2005 to May 2008 period. The 196 drivers exposed to buprenorphine or methadone on the day of crash were young, essentially males, with an important co-consumption of other substances (alcohol and benzodiazepines). Injured drivers exposed to buprenorphine or methadone on the day of crash, had an increased risk of being responsible for the crash (odds ratio (OR)=2.02, 95% confidence interval (CI): 1.40, 2.91). Conclusions: Users of methadone and buprenorphine were at increased risk of being responsible for injurious road traffic crashes. This risk is probably the combined result of risky behaviors and treatments