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)
Publication 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 1905–1934 | Ontario | Mortality Morbidity | The incidence data was not used in practice. |
Varughese et al. [8], 1979 | 1924–1978 1960–1978 1969–1976 | Canada | Total incidence Age-incidence Hospitalization | Incidence declined after vaccine introduction in 1943, as expected. |
Varughese et al. [9], 1985 | 1924–1984 1960–1984 1980–1981 | Canada | Total incidence Age-incidence Hospitalization | 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 1988–2002 | Canada | Total incidence Age-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 1991–2006 | Canada | age-incidence hospitalization | 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 1980–2012 1991–2012 1991–2011 | Canada | total incidence age-incidence hospitalization hospitalization | 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 2006–2013 | New Brunswick | age-incidence region-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 zone-incidence | Outbreaks detected based on comparison with baseline incidence in 2008 and 2012. Majority of cases had not received adequate vaccination. |