This is a summary, written by members of the CITF Secretariat, of:

Fell DB, Török E, Sprague AE, Regan AK, Dhinsa T, Alton GD, Dimanlig-Cruz S, MacDonald SE, Buchan SA, Kwong JC, Wilson SE, Håberg SE, Gravel CA, Wilson K, Dunn SI, Shah PS, El-Chaâr D, Barrett J, Walker MC, Okun N, Dougan SD. Temporal trends and determinants of COVID-19 vaccine coverage and series initiation during pregnancy in Ontario, Canada, December 2020 to December 2021: A population-based retrospective cohort study. Vaccine. 2023 Feb 3. doi:

The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.

Despite the fact that pregnant individuals were prioritized for COVID-19 vaccination in late April 2021, a CITF-funded study, published in Vaccine, showed that COVID-19 vaccine coverage with at least one dose among pregnant individuals (71.2%) remained lower than in the general population of reproductive-age females (88%) at the end of 2021. Among pregnant individuals in December 2021, only 12.5% had received a third dose. This research was led by CITF-funded researcher Dr. Deshayne Fell (University of Ottawa), in collaboration with Dr. Jeffrey Kwong (University of Toronto) and Dr. Kumanan Wilson (University of Ottawa).

Key findings:

  • Among 221,190 pregnant individuals, vaccine coverage (one dose or more before or during pregnancy) increased from 0.03% in December 2020 to 71.2% by December 2021.
  • In May 2021, there were large differences in vaccine coverage across categories of maternal age, neighborhood income quintile, and neighborhood quintile of material deprivation. However, these differences decreased over time between May and December 2021.
  • Lower vaccination initiation during pregnancy was associated with being under 25 years of age, being a smoker, reporting substance use during pregnancy, not having a first trimester prenatal care visit, residing in rural (compared to urban) areas, and residing in neighborhoods with the lowest income and highest material deprivation.
  • Vaccine series initiation was marginally higher among individuals with pre-existing medical conditions.

This study highlighted the lower vaccine coverage in pregnant individuals and identified sociodemographic, health-related and pregnancy-related factors associated with initiating vaccination during pregnancy. These findings can help inform public health strategies to increase COVID-19 vaccine acceptance among pregnant people.

Data from Ontario’s Better Outcomes Registry & Network (BORN) were linked to the COVID-19 vaccine database, COVaxON, and included pregnant individuals between December 14, 2020, and December 31, 2021.

These findings are presented in an infographic available on the BORN web site.