Safety monitoring of Imvamune vaccine during the 2022 mpox outbreak in Canada.

Background: In Canada in 2020, the indication for use of Imvamune was expanded to include immunization against smallpox, mpox and related Orthopoxvirus infection and disease in adults who are 18 years of age and older and determined to be at high risk for exposure.

Methods: Since the introduction of this new use for the vaccine and throughout the 2022 mpox outbreaks, the Public Health Agency of Canada (PHAC) has closely monitored the safety of the Imvamune vaccine through the Canadian Adverse Events Following Immunization Surveillance System (CAEFISS).

Results: This article describes reports of adverse events following immunization (AEFI) after administration of Imvamune, submitted to the CAEFISS database between May 24, 2022 and December 11, 2022, during the activation of Canada's emergency response.

Conclusion: Monitoring of AEFI reports following immunization with Imvamune submitted to CAEFISS has not identified any new or unexpected safety concerns in the Canadian adult population. The Public Health Agency of Canada continues to monitor for potential vaccine safety signals.