Urgent need to update SARS-CoV-2 mRNA vaccine product monograph information in Canada for pregnant or lactating people

Key points

• Pregnant people and their infants are at increased risk of admission to hospital or intensive care units, preterm birth, and low birth weight owing to infection with SARS-CoV-2.

• Hundreds of studies demonstrate the safety and effectiveness of SARS-CoV-2 mRNA vaccines in pregnant people and their infants, yet product monographs in Canada continue to state that these vaccines have not been tested in people who are pregnant or lactating.

• Inconsistencies between public health recommendations for vaccines and product monographs can raise hesitancy among physicians, other health professionals, and the public.

• Experience with other vaccines suggests it is possible to update vaccine product monograph language in Canada to incorporate evidence from observational studies and align with public health recommendations for vaccination in pregnancy.

• Manufacturers urgently need to update their product monographs for SARS-CoV-2 mRNA vaccine, and regulators should implement measures to support regular updates.

The National Advisory Committee on Immunization (NACI) first recommended the SARS-CoV-2 mRNA vaccines elasomeran (Moderna [Spikevax]) and tozinameran (Pfizer-BioNTech [Comirnaty]) to pregnant and lactating people in Canada in 2021.¹ The quantity and quality of that evidence have expanded since then and consistently show an increased risk of severe COVID-19 in pregnancy and that vaccines are safe and effective in pregnancy.² However, Canadian product monographs for both vaccines (updated May and September 2026) continue to include the statements “the safety and efficacy of Spikevax in pregnant women have not yet been established” and “it is unknown whether Comirnaty is excreted in human milk. A risk to the newborns/infants cannot be excluded” (Appendix 1A, www.cmaj.ca/lookup/doi/10.1503/cmaj.260860/tab-related-content). Other countries have updated SARS-CoV-2 mRNA vaccine product information regarding safety and effectiveness in pregnancy and lactation to reflect up-to-date evidence (Appendix 1A). Because inconsistencies between public health recommendations and product monographs can raise hesitancy among physicians, other health professionals, and the public, and may be used by vaccine dissenters, we argue that similar updates to Canada’s product monographs are urgently needed.

The NACI recommendations prioritize pregnant people for SARS-CoV-2 vaccination³ because pregnant people and their infants are at increased risk of admission to hospital or intensive care units, preterm birth, and low birth weight.⁴ A living systematic review of 255 mostly observational studies involving nearly 1.9 million pregnant people from 42 countries who received a SARS-COV-2 mRNA vaccine shows that vaccination is effective at preventing severe COVID-19 among pregnant people and their infants.² For example, the tozinameran vaccine decreases the risk of severe COVID-19 in pregnant people by 85.39% (95% confidence interval [CI] 59.20% to 94.77%) compared with no vaccination. Moreover, vaccination is not associated with an increased risk of adverse events, or obstetrical or neonatal complications (e.g., the relative risk of preterm birth [< 37 weeks’ gestation] after vaccination with tozinameran is 95% CI 0.75 to 1.05),² compared with no vaccination.

Despite this evidence, SARS-CoV-2 vaccine coverage among pregnant people is lower than in the general population, and concern about vaccine safety is one of the main reasons given for vaccine hesitancy.^5,6 A recommendation from a trusted physician or other health professional is a leading predictor of vaccine acceptance in pregnancy. However, inaccurate or outdated precautionary product monograph language — similar to the statements quoted above — may decrease willingness to recommend vaccination in pregnancy, as shown in a survey of 141 health professionals in 49 countries and a survey of Canadian health professionals.^7,8

Vaccine product monographs are developed to summarize product properties, indications, and contraindications, based primarily on industry-sponsored preclinical studies and clinical trials. The language is developed by vaccine manufacturers and approved by Health Canada. Once a product is authorized for use, updates to vaccine product monographs are generally required only when there is a change in the product composition, indications, or safety profile.⁹ When postmarket evidence about vaccine use in pregnancy becomes available, manufacturers can submit vaccine product monograph updates based on third-party postmarket data to Health Canada, but there is often little financial or regulatory incentive to do so.

A Canadian study of product monograph language for influenza and tetanus–diphtheria–acellular pertussis (Tdap) vaccines showed that updating information about vaccine safety and effectiveness in pregnancy influences the enthusiasm of health professionals for recommending vaccination.⁷ Through a face-to-face meeting, Delphi survey, and workshop with 41 Canadian obstetricians, family and public health physicians, allied health professionals, vaccine regulators, industry representatives, and researchers, we developed product monograph statements that reflected up-to-date evidence and met regulatory requirements.⁹ In a follow-up survey of 449 Canadian health professionals, respondents perceived the vaccines described in the consensus-developed statements to be safer and more effective in pregnancy than those in the existing Health Canada–approved statements, and were more likely to recommend the vaccines to their patients.⁷

Vaccine manufacturers subsequently applied to Health Canada for approval of updated influenza and Tdap vaccine product monographs clarifying that observational studies did not show an increased risk of adverse pregnancy outcomes. Some influenza vaccine product monographs now include NACI recommendations in the “use in pregnancy” section, and 1 states that the vaccine can be used throughout pregnancy and lactation.¹⁰

In Australia, the regulator approved new product information for 1 SARS-CoV-2 mRNA vaccine in February 2025, stating: “A large amount of observational data from pregnant women vaccinated with Spikevax during the second and third trimesters has not shown an increase in adverse pregnancy outcomes” (Appendix 1A). Statements regarding lactation also refer to observational data showing no adverse effects for infants. Comparable language appears in product information approved in Europe and the United Kingdom about pregnancy (Appendix 1A).

Several mechanisms could improve consistency between public health recommendations and vaccine product monographs. Prioritizing inclusion of pregnant and lactating people in prelicensure clinical trials and postmarket evaluation would generate evidence needed for vaccine product monographs earlier.¹¹ Regulatory authorities could require manufacturers to submit product monograph updates for regulatory review after evidence becomes available. Regulatory templates and guidelines for product information development should outline appropriate language and expectations for such updates, including the use of third-party and observational data. The European Medicines Agency guidance is one such example; it also informs guidance for some products in Australia and the UK (see Appendix 1B for comparison of product information guidance across jurisdictions).

Vaccine manufacturers and regulators in Canada should follow other countries in updating SARS-CoV2-mRNA vaccine product monographs to reflect accurate benefit and safety information regarding their use in pregnant and lactating people.