The changing age and seasonal profile of pertussis in Canada.
During the postvaccine era in Canada, most cases of pertussis have been reported in children <5 years of age, with the highest incidence, morbidity, and mortality in infants <1 year old. Population-based data, with very high laboratory confirmation rates and hospital separation and mortality statistics, chronicle the changing age and seasonal profile associated with pertussis over recent successive outbreaks in British Columbia, Canada. A large outbreak during 2000 highlights 2 important changes to the postvaccine profile. For the first time in Canada, the incidence of pertussis among preteens and teens surpassed that of all other age groups. At the same time, a decreasing incidence of pertussis among infants and preschool children highlights reduced susceptibility in the very young. Recent changes in the childhood immunization program (including introduction of an acellular pertussis vaccine), waning immunity, and changes in laboratory methods are considered in explaining these 2 simultaneous but divergent trends in the pertussis profile.
Skowronski
Danuta M
DM
University of British Columbia Centre for Disease Control, Epidemiology Services, Vancouver, British Columbia, Canada V5Z 4R4. danuta.skowronski@bccdc.ca
De Serres
Gaston
G
MacDonald
Diane
D
Wu
Wrency
W
Shaw
Carol
C
Macnabb
Jane
J
Champagne
Sylvie
S
Patrick
David M
DM
Halperin
Scott A
SA
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D002170:Canada / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D006801:Humans; D015994:Incidence; D007223:Infant; D012621:Seasons; D014917:Whooping Cough / Q000453:epidemiology*