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

Török E, Dhinsa T, Dimanlig-Cruz S, Alton GD, Sprague AE, Dunn SI, Shah PS, El-Chaâr D, Regan AK, Wilson K, Buchan SA, Kwong JC, Håberg SE, Gravel CA, Okun N, Walker MC, MacDonald SE, Wilson SE, Barrett J, Fell DB. Temporal trends and determinants of COVID-19 vaccine series initiation after recent pregnancy. Hum Vaccin Immunother. 2023 May 30:2215150. doi: https://doi.org/10.1080/21645515.2023.2215150.

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

A CITF-funded study, published in Human Vaccines & Immunotherapeutics, found that among women who gave birth in Ontario in 2021, 63.7% remained unvaccinated at the end of pregnancy. By June 30, 2022, almost two-thirds (65%) had initiated COVID-19 vaccination. Those who did not initiate vaccination after pregnancy were more likely to be in younger (<25) and older (≥40) age groups, have smoked during pregnancy, live in a neighborhood with lower income, experience more material deprivation, and have breastfed exclusively. This study was led by Dr. Deshayne Fell (University of Ottawa).

Key findings:

  • The monthly percentage of women who remained unvaccinated at the time of delivery decreased from 99.9% in January 2021, near the start of vaccine rollout in Canada, to 36.1% in December 2021.
  • The proportion of people who initiated COVID-19 vaccination after giving birth increased rapidly in the first several months after delivery, reaching 56.3% by 6 months and 65.0% by the end of follow-up in June 2022.
  • Despite this catch-up, COVID-19 vaccine initiation after delivery remained lower than among women of reproductive age in the general population: whereas 65% of unvaccinated people had initiated vaccination after pregnancy by June 2022, 92% of women of reproductive age in the general population got vaccinated during the same time period.
  • Those who did not initiate COVID-19 vaccination after pregnancy were more likely to be in younger (<25) and older (≥40) age groups, have smoked during pregnancy, live in a neighborhood with lower income, experience more material deprivation, and have breastfed exclusively.

Data from Ontario’s Better Outcomes Registry & Network (BORN) were linked to the COVID-19 vaccine database, COVaxON, and included all women who gave birth between January 1 and December 31, 2021, and had not yet been vaccinated by the end of pregnancy. They were followed to June 30, 2022 (follow-up ranged from 6 to 18 months after delivery).

The study highlights persistent issues with vaccine hesitancy and/or access to vaccination among individuals who were recently pregnant, suggesting the need for tailored interventions to improve vaccine uptake in this population.