Invasive Bacterial Diseases in Northern Canada, 2006-2013.

BACKGROUND

Northern populations were at a high risk of developing invasive bacterial diseases (IBDs). Since the last published study that described IBDs in Northern Canada, a number of vaccines against some bacterial pathogens have been introduced into the routine childhood immunization schedule.

OBJECTIVE

To describe the epidemiology of IBDs in Northern Canada from 2006 to 2013.

METHODS

Data for 5 IBDs (invasive pneumococcal disease (IPD), invasive Haemophilus influenzae disease (Hi), invasive Group A streptococcal disease (iGAS), invasive meningococcal disease (IMD) and invasive Group B streptococcal disease (GBS)) were extracted from the International Circumpolar Surveillance (ICS) program and the Canadian Notifiable Diseases Surveillance System. Incidence rates were calculated per 100,000 population per year.

RESULTS

During the study period, the incidence rates of IPD ranged from 16.84-30.97, iGAS 2.70-17.06, Hi serotype b 0-2.78, Hi non-b type 2.73-8.53, and IMD 0-3.47. Except for IMD and GBS, the age-standardized incidence rates of other diseases in Northern Canada were 2.6-10 times higher than in the rest of Canada. Over the study period, rates decreased for IPD (p=0.04), and iGAS (p=0.01), and increased for Hi type a (Hia) (p=0.004). Among IPD cases, the proportion of pneumococcal conjugate vaccine (PCV)7 serotypes decreased (p=0.0004) over the study period. Among Hi cases, 69.8% were Hia and 71.6% of these were in children under than 5 years. Of 13 IMD cases, 8 were serogroup B and 2 of them died.

CONCLUSION

Northern population in Canada, especially infants and seniors among First Nations and Inuit, are at a high risk of IPD, Hi and iGAS. Hia is the predominant serotype in Northern Canada.