Safety assessment and immunogenicity of a cell-culture-derived influenza vaccine in adults and elderly subjects over three successive influenza seasons.

Background: Adult and elderly subjects previously immunized with cell culture-derived (CCIV; Optaflu (R)) or egg-derived (TIV; Agrippal (R)) trivalent influenza vaccines were enrolled in two extension studies (E1 and E2) to evaluate safety and immunogenicity after revaccination with CC IV/TIV alone or in combination with concomitant pneumococcal vaccine (PV). Methods: Adults and elderly subjects (n = 2609) were randomized 1:1 in E1 and allocated 3:1 in E2 to receive CC IV/TIV. In E2, a subset of elderly subjects was randomized to receive CC IV/TIV, with or without PV. Adverse reactions were monitored for six months and immunogenicity was assessed by hemagglutination inhibition (HI) assay using CHMP criteria. Results: Overall, the safety profile of both vaccines was similar, no serious adverse events related to either vaccine occurred. Mild or moderate pain was the most commonly reported reaction. Reactogenicity was slightly higher in elderly subjects receiving CC IV/TIV concomitantly with PV [46% vs. 37%; p = non-significant (NS)]. Both vaccines met CHMP licensure criteria for adults and elderly subjects. With concomitant CC IV and PV, all three CHMP criteria were met for A/H1N1 and A/H3N2, whereas the B strain only met seroprotection and GMR criteria. Conclusions: Safety and immunogenicity of CC IV was not influenced by the type of vaccine received previously or by concomitant PV administration.