Safety of the Northern Hemisphere 2014/2015 formulation of the inactivated split-virion intramuscular trivalent influenza vaccine

• Phase IV study on 2014/2015 Northern Hemisphere Vaxigrip.
• Compared rates of solicited reactions in individuals ⩾6 months with historical data.
• No clinically significant increases in frequencies of solicited reactions.
• No specific concerns identified for the 2014/2015 Northern Hemisphere formulation.
• The 2014/2015 Northern Hemisphere formulation of Vaxigrip meets EU requirements.

In the current study, the safety of the 2014/2015 Northern Hemisphere formulation of Vaxigrip® (Sanofi Pasteur) was assessed to satisfy European Union requirements. Individuals ⩾6 months of age eligible for seasonal influenza vaccination were included. Children 6 months–8 years of age received one dose (0.25 ml for 6–35 mo; 0.5 ml for 3–8 y) on day 0, and those who were previously unvaccinated received a second dose of the same volume on day 28. Participants ⩾9 years of age received one full dose (0.5 ml) on day 0. Frequency categories for solicited reactions were compared with historical data for the closest age group available. A total of 527 participants were included (6 mo–5 y, n = 106; 6–12 y, n = 105; 13–17 y, n = 106; 18–65 y, n = 105; >65 y, n = 105). Frequency categories were higher in this study than for the historical comparator for fever (very common vs. common) in participants 6 months–5 years of age; shivering (very common vs. common), rash (uncommon vs. very rare), and grade 3 injection-site induration (common vs. uncommon) in participants 6–12 years of age; and shivering in participants 13–17 years of age (very common vs. common) and >65 years of age (very common vs. common). However, these increases were not considered clinically significant because confidence intervals for proportions were overlapping and because most of the reactions were of grade 1 to 2 and resolved rapidly and spontaneously. No treatment-related serious adverse events were recorded and no safety concerns or safety signals were detected. These results indicate that the 2014/2015 Northern Hemisphere formulation of Vaxigrip was well tolerated and safe to use in all age groups, with no specific concerns identified, although the study was not powered to detect rare or very rare events.