Vaccine-Preventable Diseases

Meningococcal

Invasive meningococcal disease (IMD) is endemic in Canada, showing periods of increased activity roughly every 10 to 15 years with no consistent pattern. The incidence rate varies considerably with different sero-groups, age groups, geographic locations and time. Implementation of universal meningococcal C immunization programs will also affect disease epidemiology.

Since 1985, the overall incidence of IMD has remained at or below 2 per 100,000 per year (range 0.5 to 2.1). Overall, the incidence rate has been highest among children < 1 year of age and then declines as age increases, except for a smaller peak in the 15 to 19 year age group. An average of 298 cases of meningococcal disease have been reported annually. Disease occurs year round, but there is seasonal variation with the majority of cases occurring in the winter months.

Serogroups A and C Neisseria meningitidis were the groups most frequently identified from 1971 to 1974. From 1975 to 1989, serogroup B predominated. Since 1993, serogroups B and C have been responsible for most of the cases of endemic disease in Canada (incidence rates ranging between 0.13 to 0.65 per 100,000 population and 0.2 to 0.44 per 100,000 population for C and B respectively). However, there has been less fluctuation in the incidence of serogroup B than of serogroup C disease over time. Between the years 2000 and 2003, the average number of serogroup C cases per year in children < 1 year was 4 (range 1-8). In those aged 1-4 the average was 9 (range 4-14). During the same time period, the average number of cases in the 15-19 and 20-24 age groups was 25 (range 12-40) and 13 (range 5-18) respectively. Meningococcal outbreaks are almost exclusively due to serogroup C. There were sporadic localized outbreaks and periods of elevated incidence of serogroup C disease during 1989-1993 and 1999-2001. Immunization campaigns using serogroup C polysaccharide and conjugate vaccines were implemented in some regions during the 1999-2001 out-break period. Recent data suggest that incidence rates of serogroup C are decreasing; however, more data are needed.

An increasing trend in the incidence of serogroup Y disease has been observed in the United States during the past decade, although no such trends have been observed in Canada over this time. In this country, from 1993 to 2003, serogroup Y incidence has remained relatively stable at 0.06 to 0.13 per 100,000 population per year (average 28 confirmed cases per year, range 17 to 41). Serogroup Y disease has tended to affect older adults (median age 45 years, range 0-94).

Incidence rates for serogroup W135 have remained below 0.05 per 100,000 population. Cases of serogroup A disease remain rare in Canada (< 10 cases reported between 1993 and 2005).

The epidemiology of meningococcal disease varies throughout the world. International travellers should be aware of the risk of IMD at their destination of choice. IMD occurs sporadically worldwide and in focal epidemics. The traditional endemic or hyperendemic areas of the world (the "meningitis belt") include the savannah areas of sub-Saharan Africa extending from Gambia and Senegal in the west to Ethiopia and Western Eritrea in the east. Health care providers advising Canadian travellers should remain current with global meningococcal activity. The Committee to Advise on Tropical Medicine and Travel (CATMAT) provides guidelines for health care providers counselling Canadian international travellers on meningococcal vaccination. In deciding on the need for immunization, there should be particular consideration of the destination to be visited, the nature and duration of exposure, and the age and health of the traveller. Current meningococcal outbreak information can be obtained through the Public Health Agency of Canada, Travel Medicine Program (http://www.travelhealth.gc.ca) and the World Health Organization (WHO) (http://www.who.int/csr/don/archive/disease/meningococcal_disease/en/)

Source: Canadian Immunization Guide, 7^th edition, 2006

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Links to more information

Guidelines and Recommendations

• For information about Meningococcal vaccine, see the Canadian Immunization Guide, 7^th edition 2006
• Guidelines for the Prevention and Control of Meningococcal Disease

Information Sheets

• Meningococcal Vaccine - It's Your Health

Travel Medicine Program

• Meningococcal Disease

Additional Resources

• Enhanced surveillance of invasive meningococcal disease in Canada: 1 January, 2002, through 31 December, 2003