Long-term trends in invasive pneumococcal disease in Manitoba, Canada.

Invasive pneumococcal disease (IPD) remains a significant public health problem in Manitoba, Canada although publically-funded pneumococcal conjugate (PCV7 and PCV13) and polysaccharide (PPV23) vaccination programs exist. We analyzed routine surveillance and administrative health data to examine trends in IPD rates as these vaccines were introduced. Data on all individuals with a laboratory-confirmed diagnosis of IPD between 2001 and 2014 were obtained from the provincial Communicable Diseases Surveillance database and linked with Manitoba's provincial immunization registry and physician and hospital databases. We calculated IPD incidence rates overall, by serotype and for different population subgroups defined by socio-demographic and clinical (e.g., chronic diseases, immune status) characteristics. Annual IPD incidence (95%CI) was 8.6 (8.2-9.1)/100,000 people during the study period (n = 1092), and rates were higher in recent years and in regions with predominately indigenous populations. Reduction in the incidence of serotypes included in PCV7 have been offset by rising rates of PCV13-only serotypes in children, and more recently by rising rates of PPV-only serotypes and non-vaccine serotypes among young children and older adults (≥ 65 years). Rates were 3 times higher in those with a chronic disease and highest (> 175-fold) among alcoholics, organ-transplant, and chronic kidney failure patients. The case fatality rate was 12.0% within 30 d of diagnosis. Despite the introduction of several vaccination programs, overall rates of IPD have not declined in Manitoba in the last decade, due to increase in incidence of non-PCV7 serotypes. A disproportionately high burden of disease impacts indigenous communities and people with chronic disease.

Pandemic H1N1 Vaccination and Incidence of Acute Disseminated Encephalomyelitis in Manitoba.

BACKGROUND: An increased incidence of hospital admissions coded as acute disseminated encephalomyelitis (ADEM) was noted in Winnipeg, Manitoba, Canada, during the second wave of the influenza pandemic from October 2009 to March 2010. However, it was not clear whether this was due to heightened awareness of potential neurological complications of influenza or influenza vaccination or an actual increase in the number of cases. METHODS: We extracted data from the charts of 139 patients hospitalized with an International Classification of Diseases-10 discharge code indicating ADEM (G04.0) or unspecified noninfectious encephalitis or myelitis (G04.8, G04.9) between January 2006 and December 2012. Clinical and laboratory data were reviewed by a neurologist, and diagnoses were determined using the Brighton criteria. RESULTS: Over the entire study period, there were 22 cases of ADEM. During the peak pandemic period (April-December 2009), seven patients were hospitalized with ADEM, corresponding to a rate of 7.8/million/year; 4.7 (95% confidence interval: 1.9-11.4) times higher than the rate before or after the pandemic period. Only one patient with ADEM had received the monovalent A(H1N1)pdm09 vaccine within 12 weeks of hospitalization. CONCLUSIONS: We have found an increased incidence of ADEM during the pandemic period that may be related, at least in part, to the increased incidence of influenza during that period. However, there was no temporal relationship with the administration of A(H1N1)pdm09 or seasonal influenza vaccines. Our study provides reassurance that use of these vaccines was not associated with increased risk of ADEM.

Outbreak of invasive Streptococcus pneumoniae serotype 12F among a marginalized inner-city population in Winnipeg, Canada, 2009-2011.

BACKGROUND: In 2010, Winnipeg, Canada, experienced a doubling of invasive pneumococcal disease (IPD) rates, with a significant increase in the number of cases due to Streptococcus pneumoniae serotype 12F, which previously had accounted for very few cases each year. METHODS: All serotype 12F IPD cases reported between September 2009 and January 2011 were reviewed. Pulsed-field gel electrophoresis (PFGE) and multilocus variable number tandem repeat analysis (MLVA) were conducted on all isolates. PFGE and MLVA patterns identified several possible clusters. Additional interviews were conducted to obtain information on risk factors and outcomes. RESULTS: Between September 2009 and January 2011, 169 cases of IPD were identified. The number of IPD cases due to 12F serotype increased sharply from about 3-4 cases per year (6% of IPD cases) in 2007-2009 to 28 (29%) in 2010. All 12F isolates belonged to a single sequence type (ST218), and they were generally susceptible to penicillin and fluoroquinolones but not to erythromycin. Compared with cases caused by other serotypes, patients with serotype 12F were more likely to be homeless, reside in low-income inner-city communities, and engage in substance abuse, including intravenous and crack cocaine use. Subclusters identified using MLVA had even higher rates of homelessness and substance use. CONCLUSIONS: An immunization campaign targeting high-risk groups was undertaken with pneumococcal polysaccharide vaccine, and subsequently rates of serotype 12F decreased. To our knowledge, this is the largest documented community outbreak of serotype 12F IPD and the first report of an outbreak of IPD serotype 12F in a marginalized urban population in Canada.