Pertussis Surveillance in Canada: Trends to 2012

Figure Long Descriptions

Figure 1. Reported cases and incidence rate (per 100,000 population) of pertussis in Canada by year, 1924 to 2012*

*Case data from 1924 to 2011 were obtained from the Canadian Notifiable Diseases Surveillance System. Case data for 2012 were obtained directly from provinces and territories by CIRID and are preliminary. PEI did not report 1924-1928; Newfoundland did not report until 1949; Yukon did not report 1924-1955; Northwest Territories did not report 1924-1958; Nunavut data for 1999 are only partial, for 2007 & 2009 are missing, and for 2008, 2010-2011 are preliminary. Population data (July 1st annual estimates) were obtained from Statistics Canada.

This is a combined bar and line graph showing the number of pertussis cases, in bars, and the incidence rate of pertussis per 100,000 population, using a line, in Canada over time. The primary y axis is the number of cases and ranges from 0 to 25,000. The secondary y axis is the incidence rate per 100,000 population and ranges from 0 to 250 cases per 100,000. The x axis is year and ranges from 1924 to 2012. The years in which immunization programs were introduced are also depicted as follows:

1943 = whole cell vaccine
1981 to 1985 = adsorbed whole cell vaccine
1997 to 1998 = acellular vaccine
1999 to 2004 = adolescent acellular vaccine

The overall trend of the graph can be broken down into six sections:

  1. An increase between 1924 and 1934, with cases increasing from 6,377 to 19,484 and incidence rate increasing from 68 to 181 cases per 100,000.
  2. Stable between 1935 and 1943, with the number of cases ranging between 16,003 and 19,878 and the incidence rate ranging between 144 and 175 cases per 100,000.
  3. A decrease from 1943 to 1975 and stable until 1989, at which point cases ranged between 1301 and 3387 and incidence rates between 5 and 13 cases per 100,000.
  4. A re-emergence in the 1990s with major peaks in activity occurring in 1990 (cases= 8,330; incidence rate= 30 cases per 100,000), 1994 (cases=10,117; incidence rate= 35 cases per 100,000) and 1998 (cases=8,896 incidence rate= 30 cases per 100,000).
  5. A decrease from 1998 to 2011, with cases and incidence rate declining steadily to 697 cases and an incidence rate of 2 cases per 100,000.
  6. A sharp increase in 2012 to 4,845 cases and an incidence rate of 13.9 per 100,000.

Within each overarching trend described above, peaks in activity are observed every 2 to 5 years.

Figure 2. Incidence rate (per 100,000 population) of pertussis reports in Canada by age group (in years) and year, 1980 to 2012*

*Case data from 1980 to 2011 were obtained from the Canadian Notifiable Diseases Surveillance System. Case data for 2012 were obtained directly from provinces and territories by CIRID and are preliminary. Nunavut data for 1999 are only partial, for 2007 & 2009 are missing, and for 2008, 2010-2011 are preliminary. Population data (July 1st annual estimates) were obtained from Statistics Canada.

This is a line graph that shows the incidence rate of pertussis per 100,000 population by age group in years in Canada over time. The y axis is the incidence rate per 100,000 population and ranges from 0 to 300. The x axis is year and ranges from 1980 to 2012. In the graph there is a line for each of 11 age groups (<1, 1 to 4, 5 to 9, 10 to 14, 15 to 19, 20 to 24, 25 to 29, 30 to 39, 40 to 59, >60, and unknown); however, the incidence rates of cases over 15 years of age and of those with unknown age are so low compared to the younger age groups the values are not discernible.

The less than one year age group has the highest incidence each year. The second highest incidence rate is the 1 to 4 year age group from 1980 to 1996, the 5 to 9 age group from 1997 to 1999, the 10 to 14 age group from 2000 to 2005, the 1 to 4 age group from 2006 to 2011 and the 10 to 14 age group in 2012. The less than one group had its lowest incidence in 1984 with 25 cases per 100,000 and highest incidence in 1994 with 270 cases per 100,000. In 2012, the less than one group had 121 cases per 100,000.

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