A chimeric hemagglutinin-based universal influenza virus vaccine approach induces broad and long-lasting immunity in a randomized, placebo-controlled phase I trial.

Seasonal influenza viruses constantly change through antigenic drift and the emergence of pandemic influenza viruses through antigenic shift is unpredictable. Conventional influenza virus vaccines induce strain-specific neutralizing antibodies against the variable immunodominant globular head domain of the viral hemagglutinin protein. This necessitates frequent re-formulation of vaccines and handicaps pandemic preparedness. In this completed, observer-blind, randomized, placebo-controlled phase I trial (NCT03300050), safety and immunogenicity of chimeric hemagglutinin-based vaccines were tested in healthy, 18-39-year-old US adults. The study aimed to test the safety and ability of the vaccines to elicit broadly cross-reactive antibodies against the hemagglutinin stalk domain. Participants were enrolled into five groups to receive vaccinations with live-attenuated followed by AS03-adjuvanted inactivated vaccine (n = 20), live-attenuated followed by inactivated vaccine (n = 15), twice AS03-adjuvanted inactivated vaccine (n = 16) or placebo (n = 5, intranasal followed by intramuscular; n = 10, twice intramuscular) 3 months apart. Vaccination was found to be safe and induced a broad, strong, durable and functional immune response targeting the conserved, immunosubdominant stalk of the hemagglutinin. The results suggest that chimeric hemagglutinins have the potential to be developed as universal vaccines that protect broadly against influenza viruses.

Immunogenicity of chimeric haemagglutinin-based, universal influenza virus vaccine candidates: interim results of a randomised, placebo-controlled, phase 1 clinical trial.

BACKGROUND: Influenza viruses cause substantial annual morbidity and mortality globally. Current vaccines protect against influenza only when well matched to the circulating strains. However, antigenic drift can cause considerable mismatches between vaccine and circulating strains, substantially reducing vaccine effectiveness. Moreover, current seasonal vaccines are ineffective against pandemic influenza, and production of a vaccine matched to a newly emerging virus strain takes months. Therefore, there is an unmet medical need for a broadly protective influenza virus vaccine. We aimed to test the ability of chimeric H1 haemagglutinin-based universal influenza virus vaccine candidates to induce broadly cross-reactive antibodies targeting the stalk domain of group 1 haemagglutinin-expressing influenza viruses. METHODS: We did a randomised, observer-blinded, phase 1 study in healthy adults in two centres in the USA. Participants were randomly assigned to one of three prime-boost, chimeric haemagglutinin-based vaccine regimens or one of two placebo groups. The vaccine regimens included a chimeric H8/1, intranasal, live-attenuated vaccine on day 1 followed by a non-adjuvanted, chimeric H5/1, intramuscular, inactivated vaccine on day 85; the same regimen but with the inactivated vaccine being adjuvanted with AS03; and an AS03-adjuvanted, chimeric H8/1, intramuscular, inactivated vaccine followed by an AS03-adjuvanted, chimeric H5/1, intramuscular, inactivated vaccine. In this planned interim analysis, the primary endpoints of reactogenicity and safety were assessed by blinded study group. We also assessed anti-H1 haemagglutinin stalk, anti-H2, anti-H9, and anti-H18 IgG antibody titres and plasmablast and memory B-cell responses in peripheral blood. This trial is registered with ClinicalTrials.gov, number NCT03300050. FINDINGS: Between Oct 10, 2017, and Nov 27, 2017, 65 participants were enrolled and randomly assigned. The adjuvanted inactivated vaccine, but not the live-attenuated vaccine, induced a substantial serum IgG antibody response after the prime immunisation, with a seven times increase in anti-H1 stalk antibody titres on day 29. After boost immunisation, all vaccine regimens induced detectable anti-H1 stalk antibody (2·2-5·6 times induction over baseline), cross-reactive serum IgG antibody, and peripheral blood plasmablast responses. An unsolicited adverse event was reported for 29 (48%) of 61 participants. Solicited local adverse events were reported in 12 (48%) of 25 participants following prime vaccination with intramuscular study product or placebo, in 12 (33%) of 36 after prime immunisation with intranasal study product or placebo, and in 18 (32%) of 56 following booster doses of study product or placebo. Solicited systemic adverse events were reported in 14 (56%) of 25 after prime immunisation with intramuscular study product or placebo, in 22 (61%) of 36 after immunisation with intranasal study product or placebo, and in 21 (38%) of 56 after booster doses of study product or placebo. Disaggregated safety data were not available at the time of this interim analysis. INTERPRETATION: The tested chimeric haemagglutinin-based, universal influenza virus vaccine regimens elicited cross-reactive serum IgG antibodies that targeted the conserved haemagglutinin stalk domain. This is the first proof-of-principle study to show that high anti-stalk titres can be induced by a rationally designed vaccine in humans and opens up avenues for further development of universal influenza virus vaccines. On the basis of the blinded study group, the vaccine regimens were tolerable and no safety concerns were observed. FUNDING: Bill & Melinda Gates Foundation.

Quadrivalent Influenza Vaccine Prevents Illness and Reduces Healthcare Utilization Across Diverse Geographic Regions During Five Influenza Seasons: A Randomized Clinical Trial.

BACKGROUND: We evaluated an inactivated quadrivalent influenza vaccine (IIV4) in children 6-35 months of age in a phase III, observer-blind trial. METHODS: The aim of this analysis was to estimate vaccine efficacy (VE) in preventing laboratory-confirmed influenza in each of 5 independent seasonal cohorts (2011-2014), as well as vaccine impact on healthcare utilization in 3 study regions (Europe/Mediterranean, Asia-Pacific and Central America). Healthy children were randomized 1:1 to IIV4 or control vaccines. VE was estimated against influenza confirmed by reverse transcription polymerase chain reaction on nasal swabs. Cultured isolates were characterized as antigenically matched/mismatched to vaccine strains. RESULTS: The total vaccinated cohort included 12,018 children (N = 1777, 2526, 1564, 1501 and 4650 in cohorts 1-5, respectively). For reverse transcription polymerase chain reaction confirmed influenza of any severity (all strains combined), VE in cohorts 1-5 was 57.8%, 52.9%, 73.4%, 30.3% and 41.4%, respectively, with the lower limit of the 95% confidence interval >0 for all estimates. The proportion of vaccine match for all strains combined in each cohort was 0.9%, 79.3%, 72.5%, 24.1% and 28.6%, respectively. Antibiotic use associated with influenza illness was reduced with IIV4 by 71% in Europe, 36% in Asia Pacific and 59% in Central America. CONCLUSIONS: IIV4 prevented influenza in children 6-35 months of age in each of 5 separate influenza seasons in diverse geographical regions. A possible interaction between VE, degree of vaccine match and socioeconomic status was observed. The IIV4 attenuated the severity of breakthrough influenza illness and reduced healthcare utilization, particularly antibiotic use.

Pandemic influenza virus vaccines boost hemagglutinin stalk-specific antibody responses in primed adult and pediatric cohorts.

Licensed influenza virus vaccines target the head domain of the hemagglutinin (HA) glycoprotein which undergoes constant antigenic drift. The highly conserved HA stalk domain is an attractive target to increase immunologic breadth required for universal influenza virus vaccines. We tested the hypothesis that immunization with a pandemic influenza virus vaccine boosts pre-existing anti-stalk antibodies. We used chimeric cH6/1, full length H2 and H18 HA antigens in an ELISA to measure anti-stalk antibodies in recipients participating in clinical trials of A/H1N1, A/H5N1 and A/H9N2 vaccines. The vaccines induced high titers of anti-H1 stalk antibodies in adults and children, with higher titers elicited by AS03-adjuvanted vaccines. We also observed cross-reactivity to H2 and H18 HAs. The A/H9N2 vaccine elicited plasmablast and memory B-cell responses. Post-vaccination serum from vaccinees protected mice against lethal challenge with cH6/1N5 and cH5/3N4 viruses. These findings support the concept of a chimeric HA stalk-based universal influenza virus vaccine. clinicaltrials.gov: NCT02415842.

Clinical Presentation of Influenza in Children 6 to 35 Months of Age: Findings From a Randomized Clinical Trial of Inactivated Quadrivalent Influenza Vaccine.

BACKGROUND: In an exploratory analysis of an inactivated quadrivalent influenza vaccine (IIV4) trial in children 6-35 months without risk factors for influenza, we evaluated clinical presentation of influenza illness and vaccine impact on health outcomes. METHODS: This phase III trial was conducted in 13 geographically diverse countries across 5 influenza seasons (2011-2014). Children were randomized 1:1 to IIV4 or control. Active surveillance was performed for influenza-like episodes (ILE); influenza was confirmed by reverse transcription polymerase chain reaction (RT-PCR). The total vaccinated cohort was evaluated (N = 12,018). RESULTS: 5702 children experienced ≥1 ILE; 356 (IIV4 group) and 693 (control group) children had RT-PCR-confirmed influenza. Prevalence of ILE was similar in RT-PCR-positive and RT-PCR-negative cases regardless of vaccination. Breakthrough influenza illness was attenuated in children vaccinated with IIV4; moderate-to-severe illness was 41% less likely to be reported in the IIV4 group than the control group [crude odds ratio: 0.59 (95% confidence intervals: 0.44-0.77)]. Furthermore, fever >39°C was 46% less frequent following vaccination with IIV4 than with control [crude odds ratio: 0.54 (95% confidence intervals: 0.39-0.75)] in children with breakthrough illness. Health outcome analysis showed that, each year, IIV4 would prevent 54 influenza cases per 1000 children and 19 children would need to be vaccinated to prevent 1 new influenza case. CONCLUSIONS: In addition to preventing influenza in 50% of participants, IIV4 attenuated illness severity and disease burden in children who had a breakthrough influenza episode despite vaccination.

Anamnestic Immune Response and Safety of an Inactivated Quadrivalent Influenza Vaccine in Primed Versus Vaccine-Naïve Children.

BACKGROUND: It has not yet been demonstrated whether 2 doses of inactivated quadrivalent influenza vaccine (IIV4) prime a booster response in infants. We evaluated the anamnestic immune response to an IIV4 in children 17-48 months of age. METHODS: Children were randomized to 2 doses of IIV4 or control in the primary phase III study (NCT01439360). One year later, in an open-label revaccination extension study (NCT01702454), a subset of children who received IIV4 in the primary study (primed group) received 1 IIV4 dose and children who received control in the primary study (unprimed) received 2 IIV4 doses 28 days apart. The primary objective was to evaluate hemagglutination inhibition (HI) antibody titers 7 days after first IIV4 vaccination in the per-protocol cohort (N = 224 primed; N = 209 unprimed). Neutralizing and antineuraminidase antibodies were also measured. Safety was analyzed in the total vaccinated cohort (N = 241 primed; N = 229 unprimed). RESULTS: An anamnestic response was observed in primed children relative to unprimed controls, measured by age-adjusted geometric mean HI titer ratios against strains homologous (A/H1N1: 9.0; B/Victoria: 3.9) and heterologous (A/H3N2: 2.7; B/Yamagata: 6.7) to those in the primary vaccination series. The anamnestic response in primed children included increases in neutralizing antibodies (mean geometric increase: 5.0-10.6) and antineuraminidase antibodies (4.9-8.8). No serious adverse events related to vaccination were reported. CONCLUSIONS: In this study, 2-dose priming with IIV4 induced immune memory that was recalled with 1-dose IIV4 the following year to boost HI, antineuraminidase and neutralizing antibodies, even though the IIV4 strain composition partially changed.

Prevention of vaccine-matched and mismatched influenza in children aged 6-35 months: a multinational randomised trial across five influenza seasons.

BACKGROUND: Despite the importance of vaccinating children younger than 5 years, few studies evaluating vaccine prevention of influenza have been reported in this age group. We evaluated efficacy of an inactivated quadrivalent influenza vaccine (IIV4) in children aged 6-35 months. METHODS: In this phase 3, observer-blinded, multinational trial, healthy children from 13 countries in Europe, Central America, and Asia were recruited in five independent cohorts, each in a different influenza season. Participants were randomly assigned (1:1) to either IIV4 (15 µg haemagglutinin antigen per strain per 0·5 mL dose; a single dose on day 0 for vaccine-primed children, and two doses, on days 0 and 28, for vaccine-unprimed children) or to one or two doses of a non-influenza control vaccine. Primary endpoints were moderate-to-severe influenza or all influenza (irrespective of disease severity) confirmed by RT-PCR on nasal swabs. Cultured isolates were further characterised as antigenically matched or mismatched to vaccine strains. Efficacy was assessed in the per-protocol cohort and total vaccinated cohort (time-to-event analysis), and safety was assessed in the total vaccinated cohort. FINDINGS: Between Oct 1, 2011, and Dec 31, 2014, 12 018 children were recruited into the total vaccinated cohort (6006 children in the IIV4 group and 6012 children in the control group). 356 (6%) children in the IIV4 group and 693 (12%) children in the control group had at least one case of RT-PCR-confirmed influenza. Of these 1049 influenza strains, 138 (13%) were A/H1N1, 529 (50%) were A/H3N2, 69 (7%) were B/Victoria, and 316 (30%) were B/Yamagata. Overall, 539 (64%) of 848 antigenically characterised isolates were vaccine-mismatched (16 [15%] of 105 for A/H1N1; 368 [97%] of 378 for A/H3N2; 54 [86%] of 63 for B/Victoria; 101 [33%] of 302 for B/Yamagata). Vaccine efficacy was 63% (97·5% CI 52-72) against moderate-to-severe influenza and 50% (42-57) against all influenza in the per-protocol cohort, and 64% (53-73) against moderate-to-severe influenza and 50% (42-57) against all influenza in the total vaccinated cohort. There were no clinically meaningful safety differences between IIV4 and control. INTERPRETATION: IIV4 prevented influenza A and B in children aged 6-35 months despite high levels of vaccine mismatch. Vaccine efficacy was highest against moderate-to-severe disease, which is the most clinically important endpoint associated with greatest burden. FUNDING: GlaxoSmithKline Biologicals SA.

Assessment of an optimized manufacturing process for inactivated quadrivalent influenza vaccine: a phase III, randomized, double-blind, safety and immunogenicity study in children and adults.

BACKGROUND: GSK has modified the licensed monovalent bulk manufacturing process for its split-virion inactivated quadrivalent influenza vaccine (IIV4) to harmonize the process among different strains, resulting in an increased number of finished vaccine doses, while compensating for the change from inactivated trivalent influenza vaccine (IIV3) to IIV4. To confirm the manufacturing changes do not alter the profile of the vaccine, a clinical trial was conducted to compare IIV4 made by the currently licensed process with a vaccine made by the new (investigational) process (IIV4-I). The main objectives were to compare the reactogenicity and safety of IIV4-I versus IIV4 in all age groups, and to demonstrate the non-inferiority of the hemagglutination-inhibition (HI) antibody responses based on the geometric mean titer ratio of IIV4-I versus IIV4 in children. METHODS: The Phase III, randomized, double-blind, multinational study included three cohorts: adults (18-49 years; N = 120), children (3-17 years; N = 821), and infants (6-35 months; N = 940). Eligible subjects in each cohort were randomized 1:1 to receive IIV4-I or IIV4. Both vaccines contained 15 µg of hemagglutinin antigen for each of the four seasonal virus strains. Adults and vaccine-primed children received one dose of vaccine, and vaccine-unprimed children received two doses of vaccine 28 days apart. All children aged ≥9 years were considered to be vaccine-primed and received one dose of vaccine. RESULTS: The primary immunogenicity objective of the study was met in demonstrating immunogenic non-inferiority of IIV4-I versus IIV4 in children. The IIV4-I was immunogenic against all four vaccine strains in each age cohort. The reactogenicity and safety profile of IIV4-I was similar to IIV4 in each age cohort, and there was no increase in the relative risk of fever (≥38 °C) with IIV4-I versus IIV4 within the 7-day post-vaccination period in infants (1.06; 95% Confidence Interval: 0.75, 1.50; p = 0.786). CONCLUSIONS: The study demonstrated that in adults, children, and infants, the IIV4-I made using an investigational manufacturing process was immunogenic with a reactogenicity and safety profile that was similar to licensed IIV4. These results support that the investigational process used to manufacture IIV4-I is suitable to replace the current licensed process. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02207413 ; trial registration date: August 4, 2014.

Immunogenicity and Safety of an Adjuvanted Herpes Zoster Subunit Vaccine Coadministered With Seasonal Influenza Vaccine in Adults Aged 50 Years or Older.

Background: The immunogenicity and safety of an adjuvanted herpes zoster subunit (HZ/su) vaccine when coadministered with a quadrivalent seasonal inactivated influenza vaccine (IIV4) was investigated in a phase 3, open-label, randomized clinical trial in adults aged ≥50 years. Methods: Subjects were randomized 1:1 to receive either HZ/su (varicella zoster virus glycoprotein E; AS01B Adjuvant System) and IIV4 at day 0 followed by a second HZ/su dose at month 2 (coadministration group), or IIV4 at month 0 and HZ/su at months 2 and 4 (control group). The primary objectives were the HZ/su vaccine response rate in the coadministration group and the noninferiority of the antibody responses to HZ/su and IIV4 in the coadministration compared with the control group. Safety information was collected throughout the duration of the study. Results: A total of 413 subjects were vaccinated in the coadministration group and 415 in the control group. The HZ/su vaccine response rate in the coadministration group was 95.8% (95% confidence interval, 93.3%-97.6%) and the anti-glycoprotein E GMCControl/Coadmin ratio was 1.08 (.97-1.20). The primary noninferiority objectives were met. No safety concerns were observed. Conclusions: No interference in the immune responses to either vaccine was observed when the vaccines were coadministered, and no safety concerns were identified. Clinical Trials Registration: NCT01954251.

A review of the value of quadrivalent influenza vaccines and their potential contribution to influenza control.

The contribution of influenza B to the seasonal influenza burden varies from year-to-year. Although 2 antigenically distinct influenza B virus lineages have co-circulated since 2001, trivalent influenza vaccines (TIVs) contain antigens from only one influenza B virus. B-mismatch or co-circulation of both B lineages results in increased morbidity and mortality attributable to the B lineage absent from the vaccine. Quadrivalent vaccines (QIVs) contain both influenza B lineages. We reviewed currently licensed QIVs and their value by focusing on the preventable disease burden. Modeling studies support that QIVs are expected to prevent more influenza cases, hospitalisations and deaths than TIVs, although estimates of the case numbers prevented vary according to local specificities. The value of QIVs is demonstrated by their capacity to broaden the immune response and reduce the likelihood of a B-mismatched season. Some health authorities have preferentially recommended QIVs over TIVs in their influenza prevention programmes.

Immunogenicity of AS03-adjuvanted and non-adjuvanted trivalent inactivated influenza vaccines in elderly adults: A Phase 3, randomized trial and post-hoc correlate of protection analysis.

In this study we describe the immunogenicity results from a subset of older people (N = 5187) who participated in a Phase 3 randomized, observer-blinded trial of AS03-TIV versus TIV (Fluarix™) (ClinicalTrials.gov, NCT00753272). Participants received one dose of AS03-TIV or TIV in each study year and antibody titers against the vaccine strains were assessed using hemagglutination-inhibition (HI) assay at 21 d and 180 d post-vaccination in each vaccine group in the 2008/09 (Year 1) and 2009/10 (Year 2) influenza seasons. Manufacturing consistency of 3 lots of AS03-TIV for HI antibody responses in Year 1 was a co-primary objective. In a post-hoc analysis, a statistical regression model included 4830 subjects in whom immunogenicity and laboratory-confirmed attack rate data were available; the analysis was performed to assess HI antibody titers against A/H3N2 as a correlate of protection for laboratory-confirmed A/H3N2 influenza. AS03-TIV and TIV elicited strong HI antibody responses against each vaccine strain 21 d post-vaccination in both years. The manufacturing consistency of 3 lots of AS03-TIV was demonstrated. In both years and each vaccine group, HI antibody responses were lower for A/H1N1 than the other vaccine strains. Day 180 seroconversion rates (proportion with ≥4-fold increase in titer compared with pre-vaccination titer) in Year 1 in the AS03-TIV and TIV groups, respectively, were 87.7% and 74.1% for A/H3N2, 69.7% and 59.6% for influenza B, and 58.3% and 47.4% for A/H1N1. The post-hoc statistical model based on A/H3N2 attack rates and HI antibody titers estimated that a 4-fold increase in post-vaccination titers against A/H3N2 was associated with a 2-fold decrease in the odds of A/H3N2 infection.

Immunogenicity and safety of inactivated quadrivalent and trivalent influenza vaccines in children 18-47 months of age.

BACKGROUND: Because inactivated trivalent influenza vaccines (TIVs) contain 1 influenza B strain, whereas 2 lineages may co-circulate, B lineage mismatch is frequent. We assessed an inactivated quadrivalent influenza vaccine (QIV) containing both B lineages versus TIV in young children. METHODS: Children aged 18-47 months who had received 2 doses of TIV in a study during the previous season (primed cohort, n = 192) were randomized 1:1 to receive 1 dose of TIV or QIV, and a further 407 children (unprimed cohort) were randomized 1:1 to receive 2 doses of TIV or QIV 28 days apart. Immunogenicity was assessed by hemagglutination-inhibition (HI) prevaccination and 28 days after each vaccination. Immunogenic non-inferiority QIV versus TIV for shared strains, and superiority against the alternate-lineage B strain were based on HI geometric mean titers (pooled analyses of primed and half of unprimed cohort with Day 56 immunogenicity assessment). Solicited and unsolicited adverse events were assessed during each 7- and 28-day postvaccination period, respectively (NCT00985790). RESULTS: Non-inferiority for shared strains and superiority for the alternate-lineage B strain unique to QIV was demonstrated for QIV versus TIV. QIV was immunogenic against all 4 vaccine strains and 87.0%, 88.6%, 69.8% and 97.9% of children had postvaccination titers of ≥ 1:40 against A/H1N1, A/H3N2, B/Victoria and B/Yamagata, respectively. Reactogenicity and safety of QIV was consistent with TIV. CONCLUSIONS: QIV provided superior immunogenicity for the alternate-lineage B strain compared with TIV without interfering with immune responses to shared strains. Further studies are warranted to assess QIVs in children and to establish the clinical benefits of QIV versus TIV.

Superior antigen-specific CD4+ T-cell response with AS03-adjuvantation of a trivalent influenza vaccine in a randomised trial of adults aged 65 and older.

BACKGROUND: The effectiveness of trivalent influenza vaccines may be reduced in older versus younger adults because of age-related immunosenescence. The use of an adjuvant in such a vaccine is one strategy that may combat immunosenescence, potentially by bolstering T-cell mediated responses. METHODS: This observer-blind study, conducted in the United States (US) and Spain during the 2008-2009 influenza season, evaluated the effect of Adjuvant System AS03 on specific T-cell responses to a seasonal trivalent influenza vaccine (TIV) in ≥65 year-old adults.Medically-stable adults aged ≥65 years were randomly allocated to receive a single dose of AS03-adjuvanted TIV (TIV/AS03) or TIV. Healthy adults aged 18-40 years received only TIV. Blood samples were collected on Day 0, Day 21, Day 42 and Day 180. Influenza-specific CD4+ T cells, defined by the induction of the immune markers CD40L, IL-2, IFN-γ, or TNF-α, were measured in ex vivo cultures of antigen-stimulated peripheral blood mononuclear cells. RESULTS: A total of 192 adults were vaccinated: sixty nine and seventy three ≥65 year olds received TIV/AS03 and TIV, respectively; and fifty 18 - 40 year olds received TIV. In the ≥65 year-old group on Day 21, the frequency of CD4+ T cells specific to the three vaccine strains was superior in the TIV/AS03 recipients to the frequency in TIV (p < 0.001). On Days 42 and 180, the adjusted-geometric mean specific CD4+ T-cell frequencies were also higher in the TIV/AS03 recipients than in the TIV recipients (p < 0.001). Furthermore, the adjusted-geometric mean specific CD4+ T-cell frequencies were higher in the ≥65 year-old recipients of TIV/AS03 than in the18 - 40 year old recipients of TIV on Days 21 (p = 0.006) and 42 (p = 0.011). CONCLUSION: This positive effect of AS03 Adjuvant System on the CD4+ T-cell response to influenza vaccine strains in older adults could confer benefit in protection against clinical influenza disease in this population. TRIAL REGISTRATION: (Clinicaltrials.gov.). NCT00765076.

Immunogenicity, reactogenicity and safety of an inactivated quadrivalent influenza vaccine candidate versus inactivated trivalent influenza vaccine: a phase III, randomized trial in adults aged ≥18 years.

BACKGROUND: Two antigenically distinct influenza B lineages have co-circulated since the 1980s, yet inactivated trivalent influenza vaccines (TIVs) include strains of influenza A/H1N1, A/H3N2, and only one influenza B from either the Victoria or Yamagata lineage. This means that exposure to B-lineage viruses mismatched to the TIV is frequent, reducing vaccine protection. Formulations including both influenza B lineages could improve protection against circulating influenza B viruses. We assessed a candidate inactivated quadrivalent influenza vaccine (QIV) containing both B lineages versus TIV in adults in stable health. METHODS: A total of 4659 adults were randomized 5:5:5:5:3 to receive one dose of QIV (one of three lots) or a TIV containing either a B/Victoria or B/Yamagata strain. Hemagglutination-inhibition assays were performed pre-vaccination and 21-days after vaccination. Lot-to-lot consistency of QIV was assessed based on geometric mean titers (GMT). For QIV versus TIV, non-inferiority against the three shared strains was demonstrated if the 95% confidence interval (CI) upper limit for the GMT ratio was ≤1.5 and for the seroconversion difference was ≤10.0%; superiority of QIV versus TIV for the alternate B lineage was demonstrated if the 95% CI lower limit for the GMT ratio was > 1.0 and for the seroconversion difference was > 0%. Reactogenicity and safety profile of each vaccine were assessed. Clinicaltrials.gov: NCT01204671. RESULTS: Consistent immunogenicity was demonstrated for the three QIV lots. QIV was non-inferior to TIV for the shared vaccine strains, and was superior for the added alternate-lineage B strains. QIV elicited robust immune responses against all four vaccine strains; the seroconversion rates were 77.5% (A/H1N1), 71.5% (A/H3N2), 58.1% (B/Victoria), and 61.7% (B/Yamagata). The reactogenicity and safety profile of QIV was consistent with TIV. CONCLUSIONS: QIV provided superior immunogenicity for the additional B strain compared with TIV, without interfering with antibody responses to the three shared antigens. The additional antigen did not appear to alter the safety profile of QIV compared with TIV. This suggests that the candidate QIV is a viable alternative to TIV for use in adults, and could potentially improve protection against influenza B. TRIAL REGISTRATION: Clinical Trials.gov: NCT01204671/114269.

AS03-adjuvanted versus non-adjuvanted inactivated trivalent influenza vaccine against seasonal influenza in elderly people: a phase 3 randomised trial.

BACKGROUND: We aimed to compare AS03-adjuvanted inactivated trivalent influenza vaccine (TIV) with non-adjuvanted TIV for seasonal influenza prevention in elderly people. METHODS: We did a randomised trial in 15 countries worldwide during the 2008-09 (year 1) and 2009-10 (year 2) influenza seasons. Eligible participants aged at least 65 years who were not in hospital or bedridden and were without acute illness were randomly assigned (1:1) to receive either AS03-adjuvanted TIV or non-adjuvanted TIV. Randomisation was done in an internet-based system, with a blocking scheme and stratification by age (65-74 years and 75 years or older). Participants were scheduled to receive one vaccine in each year, and remained in the same group in years 1 and 2. Unmasked personnel prepared and gave the vaccines, but participants and individuals assessing any study endpoint were masked. The coprimary objectives were to assess the relative efficacy of the vaccines and lot-to-lot consistency of the AS03-adjuvanted TIV (to be reported elsewhere). For the first objective, the primary endpoint was relative efficacy of the vaccines for prevention of influenza A (excluding A H1N1 pdm09) or B, or both, that was confirmed by PCR analysis in year 1 (lower limit of two-sided 95% CI had to be greater than zero to establish superiority). From Nov 15, to April 30, in both years, participants were monitored by telephone or site contact and home visits every week or 2 weeks to identify cases of influenza-like illness. After onset of suspected cases, we obtained nasal and throat swabs to identify influenza RNA with real-time PCR. Efficacy analyses were done per protocol. This trial is registered with ClinicalTrials.gov, number NCT00753272. FINDINGS: We enrolled 43 802 participants, of whom 21 893 were assigned to and received the AS03-adjuvanted TIV and 21 802 the non-adjuvanted TIV in year 1. In the year 1 efficacy cohort, fewer participants given AS03-adjuvanted than non-adjuvanted TIV were infected with influenza A or B, or both (274 [1·27%, 95% CI 1·12-1·43] of 21 573 vs 310 [1·44%, 1·29-1·61] of 21 482; relative efficacy 12·11%, 95% CI -3·40 to 25·29; superiority not established). Fewer participants in the year 1 efficacy cohort given AS03-adjuvanted TIV than non-adjuvanted TIV were infected with influenza A (224 [1·04%, 95% CI 0·91-1·18] vs 270 [1·26, 1·11-1·41]; relative efficacy 17·53%, 95% CI 1·55-30·92) and influenza A H3N2 (170 [0·79, 0·67-0·92] vs 205 [0·95, 0·83-1·09]; post-hoc analysis relative efficacy 22·0%, 95% CI 5·68-35·49). INTERPRETATION: AS03-adjuvanted TIV has a higher efficacy for prevention of some subtypes of influenza than does a non-adjuvanted TIV. Future influenza vaccine studies in elderly people should be based on subtype or lineage-specific endpoints. FUNDING: GlaxoSmithKline Biologicals SA.

A randomized trial of candidate inactivated quadrivalent influenza vaccine versus trivalent influenza vaccines in children aged 3-17 years.

BACKGROUND: Two antigenically distinct influenza B lineages have cocirculated since 2001, yet trivalent influenza vaccines (TIVs) contain 1 influenza B antigen, meaning lineage mismatch with the vaccine is frequent. We assessed a candidate inactivated quadrivalent influenza vaccine (QIV) containing both B lineages vs TIV in healthy children aged 3-17 years. METHODS: Children were randomized 1:1:1 to receive QIV or 1 of 2 TIVs (either B/Victoria or B/Yamagata lineage; N = 2738). Hemagglutination-inhibition assays were performed 28 days after 1 or 2 doses in primed and unprimed children, respectively. Immunological noninferiority of QIV vs TIV against shared strains, and superiority against alternate-lineage B strains was based on geometric mean titers (GMTs) and seroconversion rates. Reactogenicity and safety were also assessed (Clinicaltrials.gov NCT01196988). RESULTS: Noninferiority against shared strains and superiority against alternate-lineage B strains was demonstrated for QIV vs TIV. QIV was highly immunogenic; seroconversion rates were 91.4%, 72.3%, 70.0%, and 72.5% against A/H1N1, A/H3N2, B/Victoria, and B/Yamagata, respectively. Reactogenicity and safety of QIV was consistent with TIV. CONCLUSIONS: QIV vs TIV showed superior immunogenicity for the additional B strain without interfering with immune responses to shared strains. QIV may offer improved protection against influenza B in children compared with current trivalent vaccines.