Immunogenicity and safety of an inactivated 2012/2013 trivalent influenza vaccine produced in mammalian cell culture (Optaflu®): An open label, uncontrolled study

Background: The present study aimed to evaluate immunogenicity and safety of the 2012/2013 seasonal influenza vaccine (Optaflu®) after the World Health Organization recommended two new strains for the composition. Results: Twenty-one days post-vaccination geometric mean titers (GMTs) against A(H1N1), A(H3N2) and the B strain were 528, 935, and 201 for adults and 272, 681, and 101 for elderly subjects, respectively. The proportion of subjects with a HI titer of ≥ 40 against the three strains A(H1N1), A(H3N2) and B was 98%, 100%, and 98% in adults and 100%, 100%, and 85% in elderly subjects, respectively. Optaflu® met the CHMP criteria of the Committee for Medicinal Products for Human Use (CPMP/BWP/214/96). Pre-vaccination titers indicated seroprotection against the A(H1N1), the A(H3N2) and the B strain in 56%, 86%, and 54% of the adults and in 61%, 85%, and 40% of the elderly with highest titers against the A(H3N2) strain. In the safety analysis injection site pain (37%) and myalgia (31%) were the most common local and systemic reactions. No serious adverse events were recorded. Conclusion: The 2012/2013 seasonal influenza vaccine Optaflu® showed good immunogenicity and an acceptable safety profile in both adults and elderly. Methods: In this trial, 126 subjects (63 adults ≥18 to ≤60 y, 63 elderly ≥61 y) were vaccinated with a single dose Optaflu® containing each of the three virus strains recommended for the 2012/2013 season (A/California/7/2009(H1N1)-like strain, A/Victoria/361/2011(H3N2)-like strain, and B/Wisconsin/1/2010-like strain). Immunogenicity was assessed by hemagglutinin inhibition (HI) and single radial hemolysis (SRH) assays on day 22, the safety profile was investigated throughout the whole study period.