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Table 1 Summary of reports/studies describing the trends in incidence reports and their interpretations. (diff = difference observed, no-diff = no difference observed, age-incidence = age-stratified incidence)

From: Revisiting the epidemiology of pertussis in Canada, 1924–2015: a literature review, evidence synthesis, and modeling study

Source, year
Years of data Place(s) of data Type of data Interventions discussed and conclusions
Ross [6], 1932 1880–1929 Ontario Mortality inter-disease (diff), male/female (no-diff), urban/rural (no-diff), age-group (diff).
Museum of Health Care [7] 1880–1934
Ontario Mortality
The incidence data was not used in practice.
Varughese et al. [8], 1979 1924–1978
Canada Total incidence
Incidence declined after vaccine introduction in 1943, as expected.
Varughese et al. [9], 1985 1924–1984
Canada Total incidence
Hospitalization rates and incidence rates were almost equal, meaning that incidence reports are incomplete.
Halperin et al. [10], 1989 1985–1987 Nova Scotia Age-incidence The use of enhanced surveillance showed patterns of incidence similar to pre-vaccine. Whole-cell vaccine was not very effective.
Skowronski et al. [11], 2002 1981–2000 British Columbia Age-incidence Poor whole-cell vaccine created a cohort effect. Switch to more effective acellular changed the epidemiology. Introduction of PCR resulted in increased incidence report.
Ntezayabo et al. [12], 2003 1983–1998 Quebec Age-incidence Cohort effect, caused by poor whole-cell vaccine, was observed.
Galanis et al. [13], 2006 1924–2002
Canada Total incidence
Switch to acellular vaccine reversed observed resurgence. Cohort effect predicted caused by adolescent booster introduction. Adult booster would protect against transmission from adults to their contacts.
Vickers et al. [14], 2006 1995–2005 Saskatchewan age-incidence Whole cell or combined whole-cell/acellular worked better than pure acellular.
Bettinger et al. [15], 2007 1991–2004 Canada Hospitalization Switch from adsorbed whole-cell to acellular improved protection of small children but did not change incidence of infants.
1-dose adolescent or adult booster suggested to reinforce indirect protection to infants.
Greenberg et al. [16], 2009 1988–2004
Canada age-incidence
Both combined DTap-Hib and adolescent/adult Tdap offered effective protection against pertussis.
Fisman et al. [17], 2011 1993–2007 Greater Toronto Area Culture and PCR test records Proposed a feedback model where increasing test positivity led to increased test submissions. Seasonality may be due to cough symptom interference/misdiagnosis.
Smith et al. [18], 2014 1924–2012
Canada total incidence
The incidence trends followed expectation from vaccinations. 2012 rise was unexpected. Variations in incidence varied by province
and territory. Enhanced future monitoring was suggested.
Chambers et al. [19], 2014 1993–2013 British Columbia age-incidence Ratio of positive tests to overall test did not change much even in outbreaks, supposedly because of improved reporting. Improved future reporting was suggested.
Government of New Brunswick Report [20], 2014 2012
New Brunswick age-incidence
Age groups 10-14y had the highest incidence due to waning. Booster catch-up campaigns and adolescent (any age)/adult booster for those in contacts with infants implemented/recommended.
Deeks et al. [21], 2014 2011–2013 Ontario age-incidence for religious community/general population Age profile of pertussis in religious under-immunized community resembled prevaccine era. Many cases in immunized 10-14y was considered a sign of waning of vaccine protection.
Liu et al. [22], 2017 2004–2015 Alberta age-incidence
Outbreaks detected based on comparison with baseline incidence in 2008 and 2012. Majority of cases had not received adequate vaccination.