Measles surveillance in Canada: Trends for 2013.

OBJECTIVE: The objective of this report is to describe measles activity in Canada during 2013, in order to support the documentation and maintenance of measles elimination status. METHODS: A descriptive analysis of measles counts and incidence by age group, immunization history, hospitalization and province/territory, as well as a summary of 2013 outbreaks, was conducted using enhanced measles data captured through the Canadian Measles and Rubella Surveillance System. Genotype information and phylogenetic analysis for 2013 were summarized. RESULTS: In 2013, 83 confirmed measles cases were reported in seven provinces/territories for an incidence rate of 2.4 per 1,000,000 population. Incidence was highest in the youngest age groups (< 1 year, 1 to 4 years). Burden of disease was highest in the youngest age groups and children 10 to 14 years. Three-quarters of cases had been inadequately immunized, and 10% were hospitalized. There were nine measles outbreaks reported in 2013, one of which consisted of 42 cases in a non-immunizing community in Alberta. DISCUSSION: 2013 saw the fifth highest number of reported measles cases since 1998. While we continue to face challenges related to importation and heterogeneous immunization coverage, in 2013 Canada met or partially met all four criteria outlined by the Pan American Health Organization for measles elimination.

Measles activity in Canada: January - June 2014.

Since the beginning of 2014 to May 10, 103 cases of measles have been reported to the Public Health Agency of Canada from five provinces: British Columbia, Alberta, Saskatchewan, Manitoba and Ontario. Three factors contribute to this. First, Canadians travel more than they used to, increasing the risk in those who are not immunized of importing the disease into Canada. Second, there has been an increase in measles in countries that have high population exchange with Canada, including France (2011), the Netherlands (2013) and, most recently, the Philippines (2014). Finally, there is suboptimal immunization coverage in some areas across Canada. This year there have been 21 importations to May 10th, yet, despite how highly contagious measles is, only eight led to transmission within Canada. Strengthening immunization programs, maintaining heightened vigilance and continuing to achieve rapid containment of imported infections are essential for sustaining measles elimination.

Pertussis Surveillance in Canada: Trends to 2012.

OBJECTIVE: The purpose of this report is to provide a summary of the pertussis activity in Canada. METHODS: A descriptive analysis of pertussis incidence by year, age group, gender and province/territory was conducted using national surveillance data, clinical administrative data and vital statistics data. RESULTS: Pertussis is an endemic cyclical disease in Canada with peaks in activity occurring every 2 to 5 years. Canada has experienced a decline in pertussis activity following the introduction of routine pertussis immunization programs. The incidence of pertussis is highest in infants and children. Hospitalization and mortality are more common among infants, particularly those less than three months of age. Trends in pertussis vary by province and territory. Canada experienced a notable increase in incidence in 2012. Reasons for this increase are unknown. CONCLUSION: Our understanding of the epidemiology of pertussis in Canada could be enhanced by improved approaches for monitoring the disease. Although the peak in activity observed in 2012 could be an isolated event, further work to support outbreak response in provinces and territories, including rapid research tools and resources, should be considered.

A Survey of Pertussis Surveillance and Immunization Practices in Canada, 2012.

BACKGROUND: In 2012 there was an increase in the incidence of pertussis in the Americas. The Pan American Health Organization (PAHO) made a number of recommendations to strengthen surveillance, investigate outbreaks, to measure adequacy and timeliness of immunizations within the population and monitor policies related to high risk individuals such as health care workers and pregnant women. OBJECTIVE: To review measures taken in Canada by provinces and territories to control and prevent pertussis spread. METHODS: A survey was developed based on PAHO recommendations and distributed through the Council of Chief Medical Officers of Health to all provinces and territories. RESULTS: All provinces participated in the survey. Strong surveillance is aided by consistent use of case definitions; most provinces use the national case definition. Outbreaks are investigated at the local/provincial level. Immunization coverage is not well captured but efforts are underway to improve monitoring through surveys and immunization registries. Policies have been implemented related to high risk individuals but evaluations of these policies have not been undertaken as of yet. CONCLUSION: Based on the PAHO recommendations, Canada is well poised to provide surveillance data on pertussis. There are gaps in surveillance, in standardization among jurisdictions and in immunization coverage data which may need to be addressed to gain a better understanding of the impact of pertussis in Canada.

Enhanced surveillance of invasive meningococcal disease in Canada, 2006-2011.

OBJECTIVE: The purpose of this report is to describe the epidemiology of invasive meningococcal disease (IMD) in Canada from 2006 to 2011. METHODS: Data from the Enhanced Invasive Meningococcal Disease Surveillance System and national population estimates were selected for descriptive and inferential analyses. The geographic, demographic, seasonal and subtype distributions as well as clinical characteristics of the IMD cases were examined. Incidence and mortality rates were calculated per 100,000 population per year; 95% confidence intervals (CI) were calculated for rate comparison. The direct method was used for age standardization. Proportions were compared using the chi-squared test at a p<0.05 significance level. RESULTS: During the study period, the mean incidence rates of IMD were 0.58 (total), 0.33 (serogroup B), 0.07 (serogroup C), 0.03 (serogroup W-135) and 0.10 (serogroup Y). The median age for serogroups B, C, W-135 and Y was 16, 43, 38 and 47 years respectively. The mean age-specific incidence rates among infants under 1 year of age (7.35, CI: 5.38-9.32) and children from 1 to 4 years of age (1.89, CI: 1.54-2.24) were significantly higher than those in any other age group. The mean case fatality ratio was 8.1% (range 4.3%-14.3%). The average number of cases that occurred per month was significantly higher (p<0.0001) in winter (18 cases) than in summer (12 cases). CONCLUSION: IMD is still endemic in Canada. Although individuals at any age can be affected, infants under 1 year of age are at the greatest risk, followed by children aged 1-4 years and individuals aged 15-19 years. Following the implementation of routine childhood immunization programs with monovalent meningococcal C conjugate vaccines (MenC) in all provinces and territories (beginning in 2007), the incidence of serogroup C has decreased significantly over the study period and is now at an all-time low. Serogroup B is the leading cause of IMD, and diseases of serogroup W-135 and Y have stabilized at relatively lower incidence rates. With the addition of immunization programs using quadrivalent conjugate meningococcal vaccines (MCV4), we would expect further reductions in the incidence of meningococcal infection in Canada.