Safety and effectiveness of dose-sparing strategies for seasonal influenza vaccine

Abstract

The current evidence for the administration of intramuscular influenza vaccines suggests there is no significant difference in safety and clinical effectiveness with the use of low-dose compared to full-dose vaccines, which is promising given the predicted resource constraints in the upcoming influenza season due to the 2019 novel coronavirus. Due to the low number of studies in adults and the lack of studies assessing confirmed influenza and influenza-like illness, there remains a need for further evaluation. PURPOSE The Centre for Immunization and Respiratory Infectious Diseases of the Public Health Agency of Canada (PHAC) submitted a query regarding the safety and effectiveness of fractional dosing of seasonal influenza vaccines through the Canadian Institutes of Health Research (CIHR) Drug Safety and Effectiveness Network (DSEN). They requested that the DSEN Methods and Application Group in Indirect Comparisons (MAGIC) conduct a rapid review on this topic with an approximate 6-week timeline. The overall objective of this rapid review was to identify potentially safe and effective dose-sparing strategies for administration of seasonal influenza vaccines in healthy individuals of all ages that have been evaluated in human trials. In order to limit the scope of the work and ensure the rapid timeline could be met, this review focused only on intramuscular vaccine formulations, thus the research question was as follows: What is the safety and effectiveness of using fractional dosing strategies to deliver intramuscular seasonal influenza vaccines?