Impact of prior or concomitant seasonal influenza vaccination on MF59-adjuvanted H1N1v vaccine (Focetria™) in adult and elderly subjects

Background: When H1N1v vaccines become widely available, most elderly subjects will have already received their seasonal influenza vaccination. Adults seeking H1N1v vaccination may be offered seasonal vaccine as well. We investigated prior seasonal vaccination in adult and elderly subjects, and concomitant vaccination with seasonal vaccine in adults, on the tolerability and immunogenicity of the Novartis MF59-adjuvanted H1N1v vaccine, Focetria(R). Methods: A total of 264 adult (four groups) and 154 elderly (three groups) subjects were enrolled. The licensure study cohorts for plain (Agrippal(R)) and MF59-adjuvanted (Fluad(R)) 2009-2010 seasonal vaccines were invited to receive Focetria 3 months later, with seasonal vaccine-naive controls, and adults who received Focteria and seasonal vaccine concomitantly. Immunogenicity of all vaccines was assessed by haemagglutination inhibition on Days 1 and 22, safety and reactogenicity were monitored using patient diaries. Results: All adult and elderly groups met all the European CHMP licensing criteria for H1N1v, as did adults receiving concomitant seasonal vaccine for the three seasonal strains. Vaccines were generally well tolerated, causing no SAEs, and profiles typical of MF59-adjuvanted vaccines. Reactions were mainly mild or moderate and transient, and unaffected by prior or concomitant seasonal vaccination except for elderly subjects previously given MF59-adjuvanted seasonal vaccine, whose reaction rates to Focetria were about half those seen in groups receiving their first MF59 vaccine. Conclusion: One dose of MF59-adjuvanted H1N1v vaccine met the licensure criteria for adult and elderly subjects 3 months after seasonal vaccination, or concomitantly with seasonal vaccine in adults, without impacting the tolerability or immunogenicity of either vaccine, thus facilitating mass influenza immunisation campaigns.