July 15, 2020

Safety and effectiveness of influenza vaccine during pregnancy

Q# 19-08 – Safety and effectiveness of influenza vaccine during pregnancy

Research question:

Are influenza vaccines safe and effective for women and their newborns if received at any time during their pregnancy?


A number of recent studies on the safety of influenza vaccine in pregnancy have been published. In addition to the review, it would be beneficial to determine the safety and effectiveness of influenza vaccine during pregnancy using primary research completed within Canada. A retrospective study using an existing cohort of pregnant women would be the most feasible to assess AEFIs during pregnancy and neonatal birth outcomes and may be possible to use for assessing the vaccine effectiveness in pregnant women and children less than 6 months of age.  Vaccinated mothers pass protective antibodies via the placenta to provide passive immunity to newborns.  These antibodies are generally considered to provide passive protection to newborns up to 6 months of age, and protecting infants <6 months (before infants can receive their own vaccines) is an important outcome of the vaccine program for pregnant women.


Given that administrative databases do no have readily available information on vaccine use in any given populations, and thus cannot be performed within the Canadian Mother-Child Cohort Initiative, CAN-AIM’s proposal will use data from the 3D Cohort Study to answer the query. A Bérard is a co-investigator within the 3D Cohort Study, and thus has direct access to the study data. The 3D Cohort has been described in Fraser et al. 2016 (Fraser et al. (including A Bérard) 3D Study Group. 3D Cohort Study: The Integrated Research Network in Perinatology of Quebec and Eastern Ontario. Paediatr Perinat Epidemiol. 2016 Nov;30(6):623-632) and is presented at https://www.maelstrom-research.org/mica/individual-study/3d.

Current status:

Feasibility assessment has been approved by DSEN. Ethics approved at Ste-Justine. Transfer fund agreement has been drafted. Meanwhile, we have almost completed the analyses. Our content expert, Dr Caroline Quasi, will soon meet with us to provide further feedback and insight. After that, we are planning a meeting with the query submitters to present results.