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 AS03-adjuvanted A(H1N1)pmd09 vaccine elicited a good immune response against A(H1N1)pmd09-like virus in all treatment groups after the first and second dose, meeting and exceeding the European licensing criteria for pandemic influenza vaccines. After one dose of the AS03-adjuvanted A(H1N1)pmd09 vaccine, haemagglutination inhibition seroconversion rates ranged from 85% (95% confidence interval: 74-93%) to 93% (85-97%), seroprotection rates from 87% (76-94%) to 96% (90-99%) and geometric mean fold rise from 15 (11-19) to 20 (16-25). 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.

Flexibility of interval between vaccinations with AS03A-adjuvanted influenza A (H1N1) 2009 vaccine in adults aged 18-60 and >60 years: a randomized trial.

BACKGROUND: Flexibility of vaccination schedule and lower antigen content can facilitate pandemic vaccine coverage. We assessed the immune response and safety of AS03-adjuvanted A/California/7/2009 H1N1 pandemic vaccine containing half of the registered adult haemagglutinin (HA) antigen content, administered as a two-dose schedule at intervals of 21 days or 6 months in both young and elderly adults. METHODS: In this open-label randomized trial, healthy adults aged 18-60 years (N = 163) and >60 years (N = 143) received AS03A-adjuvanted A/California/7/2009 H1N1 vaccine containing 1.9 µg HA on Day 0. A second dose was given on Day 21 (n = 177) or Day 182 (n = 106). Haemagglutination-inhibition (HI) antibody responses were analyzed on Days 0, 21, 42, 182, 364 and additionally on Day 203 for subjects vaccinated on Day 182. Solicited and unsolicited adverse events were recorded. RESULTS: The HI antibody response in both age strata 21 days after the first dose met and exceeded all regulatory acceptance criteria although the results suggested a lower response in the older age stratum (geometric mean titres [GMTs] for HI antibodies of 420.5 for subjects aged 18-60 years and 174.4 for those >60 years). A second dose of AS03A adjuvanted A/H1N1/2009 vaccine induced a further increase in antibody titres and the response was similar whether the second dose was administered at 21 days (GMTs of 771.8 for 18-60 years and 400.9 for >60 years) or 6 months (GMTs of 708.3 for 18-60 years and 512.1 for >60 years) following the first dose. Seroprotection rates remained high at 6 months after one dose or two doses while at 12 months rates tended to be higher for the 6 month interval schedule (93.3% for 18-60 years and 80.4% for >60 years) than the 21 day schedule (82.3% for 18-60 years and 50.0% for >60 years). Reactogenicity/safety profiles were similar for both schedules, there was no evidence of an increase in reactogenicity following the second dose. CONCLUSIONS: The results indicate that flexibility in the dosing interval for AS03A adjuvanted vaccine may be possible. Such flexibility could help to reduce the logistic stress on delivery of pandemic vaccination programmes. TRIAL REGISTRATION: ClinicalTrials.gov, NCT00975884.

AS03(A)-Adjuvanted influenza A (H1N1) 2009 vaccine for adults up to 85 years of age.

BACKGROUND: Vaccination of high-risk groups was started shortly after the emergence of the influenza A (H1N1)2009 pandemic virus. METHODS: Healthy adults were enrolled into 2 age strata: 18-60 years and 160 years, and received monovalent influenza vaccine containing 3.75 microg of A/California/2009 (H1N1) hemagglutinin antigen, adjuvanted with AS03A. Hemagglutination inhibition assay-based antibody titers against H1N1 vaccine were assessed after 1 vaccine dose(primary endpoint), after which subjects were randomized 1:1 to receive no further vaccination or a second dose.Immunogenicity endpoints were European licensure criteria for influenza vaccines. Exploratory analyses assessed the effect of previous seasonal influenza vaccination on responses to the H1N1 vaccine. RESULTS: Licensure criteria for immunogenicity were fulfilled after 1 dose of H1N1 vaccine (N=240). For subjects 18-60 years of age, previous vaccination against seasonal influenza within the preceding 2 seasons resulted in significantly lower geometric mean titers (adjusted for baseline antibody titer) after 1 or 2 doses of H1N1 vaccine (P <.001 and P=.003, respectively). Transient mild or moderate injection-site pain was reported by 87.5%and 65.0% of subjects 18-60 years of age and >60 years of age, respectively, after the first dose, and in 63% of subjects overall after the second dose. CONCLUSIONS: A single dose of 3.75 microg hemagglutinin antigen, AS03A-adjuvanted H1N1 2009 vaccine was immunogenic and well tolerated in adults. In exploratory analyses (of subjects 18-60 years of age), postvaccination antibody titers were lower in subjects who had previously received seasonal influenza vaccination, compared with those who had not. This phenomenon warrants further investigation. CLINICAL TRIALS REGISTRATION: NCT00968526.

Immunogenicity and safety of AS03-adjuvanted 2009 influenza A H1N1 vaccine in children 6-35 months.

We report on the evaluation of the immunogenicity and reactogenicity/safety of AS03-adjuvanted vaccine against pandemic influenza A/H1N1/2009 in young children. In this open-label, randomized study, 157 healthy children aged 6-35 months received two doses (21 days apart) of split-virion inactivated A/California/7/2009 H1N1 vaccine containing either (i) 1.9microg hemagglutinin (HA) and AS03(B) (5.93mg tocopherol) (N=104) or (ii) 3.75mug HA and AS03(A) (11.86mg tocopherol) (N=53). At 21 days following the first dose of AS03(B)-adjuvanted vaccine (1.9microg HA) the percentage of children with hemagglutination-inhibition titers of >or=40 against the vaccine strain rose from 3.0% before vaccination to 100%. The seroconversion rate was 99% and the geometric mean titer (GMT) increased from 6 to 313. After the second dose the GMT increased further to 2008. The higher dose AS03(A)-adjuvanted 3.75microg HA vaccine did not further increase the immune response. Solicited symptoms reported within 7 days following vaccination were mainly mild to moderate. After the first dose of AS03(B)-adjuvanted vaccine (1.9microg HA) the most common solicited symptoms were pain at the injection site (35.6%) and irritability (31.7%). Fever (axillary >or=37.5 degrees C) was reported with an incidence of 20.2%. After the second dose reactogenicity tended to increase (injection site pain: 41.3%; irritability: 46.2%; fever >or=37.5 degrees C: 67.3%). Spontaneously reported adverse events with an intensity that prevented normal activities were documented for 2.9-6.7% of doses with only one event (vomiting) considered related to vaccination. There was one serious adverse event reported in the AS03(A)-adjuvanted 3.75microg HA vaccine group (traumatic brain injury) which was not considered as related to vaccination. In conclusion, these data suggest that a first dose of AS03(B)-adjuvanted A/H1N1/2009 vaccine containing 1.9microg HA in children 6-35 months old is highly immunogenic and that the overall reactogenicity profile is acceptable although reactions including fever tend to increase after a second dose.

Immunogenicity and safety in adults of one dose of influenza A H1N1v 2009 vaccine formulated with and without AS03A-adjuvant: preliminary report of an observer-blind, randomised trial.

Governments and public health officials are preparing vaccination campaigns against the 2009 influenza A H1N1v pandemic strain. We evaluated two inactivated split-virion A/California/7/2009 H1N1v pandemic vaccines formulated with/without AS03(A), an oil-in-water emulsion adjuvant system containing tocopherol. This ongoing observer-blind study randomised 130 healthy adults aged 18-60 years to receive either AS03(A)-adjuvanted H1N1 vaccine containing 5.25 microg haemagglutinin (HA) (N=64) or non-adjuvanted H1N1 vaccine containing 21 microg HA (N=66) on Days 0 and 21. We performed a first analysis of reactogenicity and serum haemagglutination-inhibition (HI) antibody responses, 21 days after dose 1. Before vaccination, 12.5% in the AS03(A)-adjuvanted group and 13.1% in the non-adjuvanted group had vaccine-homologous HI titres >or=1:40. Immune responses were robust; HI seroconversion rates were 98.2% and 95.1% and HI seroprotection rates were 98.2% and 98.4%, respectively in the AS03(A) and non-adjuvanted groups. The vaccines were well tolerated with similar adverse event profiles. Solicited injection site and general symptoms were reported more frequently for AS03(A)-adjuvanted vaccine but these were transient and mainly mild to moderate in intensity. Based on accepted immunological surrogates, these preliminary data suggest that one dose of either AS03(A)-adjuvanted H1N1v vaccine at a reduced HA dose or non-adjuvanted H1N1v vaccine at a fourfold higher dose is sufficient to immunise healthy adults. The strong immune response is consistent with prevalent immunological priming but as this and the ability to mount immune response after vaccination may be modulated by age, further investigations in children and in the elderly as well as on the persistence of the immune response are warranted.