Vaccine
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Randomized Controlled Trial Multicenter Study
Safety and immunogenicity of an AS03-adjuvanted A(H1N1)pmd09 vaccine administered simultaneously or sequentially with a seasonal trivalent vaccine in adults 61 years or older: data from two multicentre randomised trials.
During the 2009-2010 Northern Hemisphere influenza season, both seasonal and pandemic influenza vaccines were expected to be administered to elderly people, which is an important target group for influenza vaccination. Two multicentre randomised clinical studies were conducted in participants aged ≥61 years to assess the immunogenicity and reactogenicity following vaccination with two doses of an AS03-adjuvanted A(H1N1)pmd09 vaccine when either sequentially administered (21 days before first dose [N=73] or 21 days after second dose [N=72]) or co-administered (first dose [N=84] or second dose [N=84]) with a licensed trivalent seasonal influenza vaccine (TIV). Overall, 313 participants from 2 centres in Sweden (ClinicalTrials.gov, NCT00968890) and 6 centres in Germany (NCT00971425) were randomised to one of the four treatment groups. ⋯ The haemagglutination inhibition immune responses to the AS03-adjuvanted A(H1N1)pmd09 vaccine seemed lower when TIV was administered 3 weeks before, while immune responses to TIV seemed not affected by either vaccination schedule. Solicited symptoms were more frequently reported following administration of the AS03-adjuvanted A(H1N1)pmd09 vaccine compared to TIV, but these were mainly mild to moderate in intensity and transient in the four treatment groups. These results suggest that sequential or co-administration of the AS03-adjuvanted A(H1N1)pmd09 vaccine and TIV induced a good immune response to both vaccines and had a clinically acceptable safety profile in people aged ≥61 years.