Immunogenicity and safety of the Southern Hemisphere 2015 formulation of Vaxigrip

ABSTRACTAn inactivated split-virion trivalent influenza vaccine(IIV3; Vaxigrip®, Sanofi Pasteur) has been available globally since 1968. Here, we describe the results of an open-label, post- licensuretrial (EudraCT no. 2014-005078-12) to confirm the immunogenicity and safety of the Southern Hemisphere2015 formulation of IIV3. Adults18–60 years of age and > 60 years of age (60 per age group) received a single 0.5-ml intramuscular injection of IIV3. Between baseline and day 21 after vaccination, hemagglutination inhibition ( HAI) titersfor each strain in IIV3 increased, on average, by at least 11-fold for younger adultsand at least 5-fold for older adults. After vaccination, 89%–100% of the younger adultparticipants and 90%–98% of the older adultparticipants attained seroprotection ( HAI titer≥ 40) for each strain. Also, 66%–81% of younger adultsand 45%–63% of older adultsseroconverted or had a significant increase in HAI titerfor each strain. For both age groups, these post-vaccination immune resp...