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Trends and characteristics of Tdap vaccination during pregnancy in Ontario, Canada: a retrospective cohort study
Romina Fakhraei1, Stephen G Fung1, William Petrcich1
1Children's Hospital of Eastern Ontario (CHEO) Research Institute (Fakhraei, Fung, Fell); Ottawa Hospital Research Institute (Fakhraei, Wilson, Hawken, Walker); University of Ottawa (Fakhraei, Cook, Hawken, Walker, Fell); ICES uOttawa (Petrcich, Hawken, Fell), Ottawa, Ont.; ICES Central (Crowcroft, Kwong), University of Toronto (Crowcroft, Bolotin, Biringer, Dubey, Jamieson, Kwong); Public Health Ontario (Bolotin, Jamieson, Kwong), Toronto, Ont.; Kingston Health Sciences Centre (Gaudet); Queen's University (Gaudet), Kingston, Ont.; UK Health Security Agency (Amirthalingam), London, UK; Mount Sinai Hospital (Biringer), Toronto, Ont.; Bruyère Research Institute (Wilson), Ottawa, Ont.; Toronto Public Health (Dubey), Toronto, Ont.; Canadian Center for Vaccinology (Halperin); Dalhousie University (Halperin); Nova Scotia Health (Halperin); IWK Health (Halperin), Halifax, NS; Vaccine Evaluation Center (Sadarangani), BC Children's Hospital Research Institute; Department of Pediatrics (Sadarangani), University of British Columbia, Vancouver, BC; The Society of Obstetricians and Gynaecologists of Canada (Cook), Ottawa, Ont.
Insights
Maternal tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccination in Ontario significantly increased after national recommendations. Strategies are needed to improve Tdap vaccine uptake in specific pregnant populations.
Area of Science:
- Public Health
- Immunization
- Maternal Health
Background:
- In 2018, Canada's National Advisory Committee on Immunization (NACI) recommended Tdap vaccination during pregnancy.
- This recommendation aimed to protect newborns from pertussis infection.
Purpose of the Study:
- To describe trends in Tdap vaccination coverage among pregnant individuals in Ontario before and after the NACI recommendation.
- To identify factors associated with Tdap vaccination during pregnancy.
Main Methods:
- Population-based retrospective cohort study using linked health administrative databases.
- Included pregnant individuals who gave birth in Ontario hospitals between April 2012 and March 2020.
- Log-binomial regression used to identify factors associated with vaccination.
Main Results:
- Tdap vaccination coverage increased from 0.4% in 2011/12 to 29.2% in 2019/20.
- Coverage was higher among older individuals, those with no previous live births, adequate prenatal care, and care from a family physician.
- Lower coverage was associated with younger maternal age, multiple births, rural location, and higher area material deprivation.
Conclusions:
- Tdap vaccination coverage during pregnancy substantially increased in Ontario post-recommendation.
- Public health strategies should target subpopulations with lower vaccine coverage to improve uptake in the obstetric setting.
Background:
In February 2018, Canada's National Advisory Committee on Immunization (NACI) recommended tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccination during pregnancy to protect newborns against pertussis infection. We sought to describe pre- and postrecommendation trends in Tdap vaccination coverage among pregnant Ontario residents.
Methods:
Using linked health administrative databases, we conducted a population-based retrospective cohort study of all pregnant individuals who gave birth in Ontario hospitals between April 2012 and March 2020. We described Tdap vaccination patterns in pregnancy for the entire study period and before and after the NACI recommendation. We used log-binomial regression to identify characteristics associated with Tdap vaccination during pregnancy.
Results:
Among the 991 850 deliveries included, 7.0% of pregnant individuals received the Tdap vaccination during pregnancy. Vaccine coverage increased from 0.4% in 2011/12 to 29.2% in 2019/20. Coverage was highest among individuals who were older, had no previous live births, had adequate prenatal care and received maternity care primarily from a family physician. After adjustment, characteristics associated with lower coverage included younger maternal age, having a multiple birth, residing in a rural location and higher area material deprivation. In 2019/20, 71.0% of vaccinated individuals received the Tdap vaccination during the recommended gestational window (27-32 wk). Stratified analyses of the pre- and postrecommendation cohorts yielded similar findings to the main analyses with a few gradient differences after adjustment.
Interpretation:
During pregnancy, Tdap vaccination coverage increased substantially in Ontario between 2011/12 and 2019/20, most notably after recommendations for universal Tdap vaccination during pregnancy began in Canada. To further improve vaccine coverage in the obstetric setting, public health strategies should consider tailoring their programs to reach subpopulations with lower vaccine coverage.
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