Dose-Sparing H5N1 A/Indonesia/05/2005 Pre-pandemic Influenza Vaccine in Adults and Elderly Adults: A Phase III, Placebo-Controlled, Randomized Study Immunogenicity and safety of an AS03-adjuvanted H5N1 pandemic influenza vaccine in Korean adults: a phase IV, randomized, open-label, controlled study. A phase II, randomised clinical trial to demonstrate the non-inferiority of low-dose MF59-adjuvanted pre-pandemic A/H5N1 influenza vaccine in adult and elderly subjects. Broad Clade 2 Cross-Reactive Immunity Induced by an Adjuvanted Clade 1 rH5N1 Pandemic Influenza Vaccine Immunogenicity and tolerability of an AS03(A)-adjuvanted prepandemic influenza vaccine: a phase III study in a large population of Asian adults. Fast rise of broadly cross-reactive antibodies after boosting long-lived human memory B cells primed by an MF59 adjuvanted prepandemic vaccine Rapid Immunization Against H5N1: A Randomized Trial Evaluating Homologous and Cross-Reactive Immune Responses to AS03A-Adjuvanted Vaccination in Adults Heterologous Prime-Boost Vaccination with MF59-Adjuvanted H5 Vaccines Promotes Antibody Affinity Maturation towards the Hemagglutinin HA1 Domain and Broad H5N1 Cross-Clade Neutralization Cross-reactivity to highly pathogenic avian influenza H5N1 viruses after vaccination with nonadjuvanted and MF59-adjuvanted influenza A/Duck/Singapore/97 (H5N3) vaccine: a potential priming strategy. A phase II, open-label, multicentre study to evaluate the immunogenicity and safety of an adjuvanted prepandemic (H5N1) influenza vaccine in healthy Japanese adults An assessment of prime‐boost vaccination schedules with AS03A‐adjuvanted prepandemic H5N1 vaccines: a randomized study in European adults Priming with AS03 A-adjuvanted H5N1 influenza vaccine improves the kinetics, magnitude and durability of the immune response after a heterologous booster vaccination: an open non-randomised extension of a double-blind randomised primary study. Single dose vaccination with AS03-adjuvanted H5N1 vaccines in a randomized trial induces strong and broad immune responsiveness to booster vaccination in adults. Immunogenicity and Safety of H5N1 A/Vietnam/1194/2004 (Clade 1) AS03-Adjuvanted Prepandemic Candidate Influenza Vaccines in Children Aged 3 to 9 Years: A Phase II, Randomized, Open, Controlled Study Safety and cross-reactive immunogenicity of candidate AS03-adjuvanted prepandemic H5N1 influenza vaccines: a randomized controlled phase 1/2 trial in adults. MF59®-Adjuvanted H5N1 Vaccine Induces Immunologic Memory and Heterotypic Antibody Responses in Non-Elderly and Elderly Adults Pseudoparticle neutralization is a reliable assay to measure immunity and cross-reactivity to H5N1 influenza viruses. Immunogenicity and safety of an AS03-adjuvanted H7N1 vaccine in adults 65years of age and older: A phase II, observer-blind, randomized, controlled trial. A phase III, randomized, open-label study to assess the tolerability and immunogenicity of an H5N1 influenza vaccine administered to healthy adults with a 1-, 2-, 3-, or 6-week interval between first and second doses. Safety and immunogenicity of a split-virion AS03A-adjuvanted A/Indonesia/05/2005 (H5N1) vaccine in Taiwanese adults.
Background . Highly pathogenic avian influenza H5N1 viruses remain a threat to human health , with potential to become p and emic agents . Methods . This phase III , placebo-controlled , observer-blinded study evaluated the immunogenicity , cross-reactivity , safety , and lot consistency of 2 doses of oil-in-water ( AS03A ) adjuvanted H5N1 A/Indonesia/05/2005 ( 3.75 μg hemagglutinin antigen ) prep and emic c and i date vaccine in 4561 adults aged 18–91 years . Results . Humoral antibody responses in the H5N1 vaccine groups fulfilled US and European immunogenicity licensure criteria for p and emic vaccines in all age strata 21 days after the second dose . At 6 months after the administration of the primary dose , serum antibody seroconversion rates continued to fulfill licensure criteria . Neutralizing cross-clade immune responses were demonstrated against clade 1 A/Vietnam/1194/2004 . Consistency was demonstrated for 3 consecutive H5N1 vaccine lots . Temporary injection-site pain was more frequent with H5N1 vaccine than placebo ( 89.3 % and 70.7 % in the 18–64 and ≥65 years strata vs 22.2 % and 14.4 % in the placebo groups ) . Unsolicited adverse event frequency , including medically attended and serious events , was similar between groups through day 364 . Conclusions . In adults and elderly adults  , AS03A-adjuvanted H5N1 c and i date vaccine was highly immunogenic for A/Indonesia/05/2005 , with cross-reactivity against A/Vietnam/1194/2004 . Temporary injection site reactions were more frequent with H5N1 vaccine than placebo , although the H5N1 vaccine was well tolerated overall . Clinical Trials Registration . NCT00616928 BACKGROUND AS03-adjuvanted H5N1 p and emic influenza vaccines have been assessed in an extensive clinical development program conducted in North America , Europe , and Asia including children from 6 months of age , adults , and elderly adults . We evaluated AS03-H5N1 in Korean adults 18 through 60 years of age . METHODS This Phase IV , r and omized , study was conducted to assess the immunogenicity , reactogenicity , and safety of two doses ( 3.75μg of hemagglutinin antigen ) of A/Indonesia/5/2005 ( H5N1 ) adjuvanted with AS03 given 21 days apart in Korean adults . Antibody responses were assessed using hemagglutination-inhibition ( HI ) assays against the vaccine strain and a vaccine-heterologous strain ( A/Vietnam/1194/2004 ) 21 days after the second dose . A control group ( safety ) received a licensed seasonal inactivated trivalent influenza vaccine ( TIV ) . Reactogenicity was assessed for 7 days after each vaccination , and unsolicited adverse events were assessed for 182 days following vaccination in both study groups ( NCT01730378 ) . RESULTS AS03-H5N1 was immunogenic and elicited robust HI antibody responses with seroconversion rates of 100 % for the vaccine strain and 69.1 % for the heterologous strain ( N=81 ) . HI antibody responses fulfilled the European licensure criteria for immunogenicity ( primary endpoint ) . The incidence of local and systemic solicited adverse events ( reactogenicity ) was higher with AS03-H5N1 than TIV . There was no apparent difference in the rate of unsolicited adverse events in the AS03-H5N1 and TIV groups . CONCLUSION The results indicate that AS03-H5N1 vaccine is immunogenic with reactogenicity and safety findings that are consistent with the established profile of AS03-H5N1 vaccine BACKGROUND Effective planning and preparedness against a possible future A/H5N1 influenza p and emic is a major global challenge . Because dose sparing strategies are required to meet the global dem and for vaccine , efforts have focused on the development of adjuvanted vaccine formulations of relatively lower antigen content . AIM This study aim ed to demonstrate the non-inferiority of a low-antigen-dose ( 3.75 μ ) [ DOSAGE ERROR CORRECTED ] A/H5N1 pre-p and emic vaccine compared with a licensed , higher-dose ( 7.5 mg ) formulation in adult and elderly subjects . Immunogenicity was assessed according to European and U.S. licensure criteria . METHODS A total of 722 subjects were r and omized in equal numbers to receive either the licensed or low-dose formulation . All subjects received two vaccine doses administered three weeks apart . Immunogenicity was assessed three weeks after the administration of each vaccine dose by hemagglutination inhibition ( HI ) , single radial haemolysis ( SRH ) and microneutralization assays ( MN ) . Local and systemic reactions were assessed over a seven day period post-vaccination . Adverse events were recorded throughout . RESULTS The low-dose vaccine was demonstrated to be non-inferior to the licensed formulation in terms of antibody titres against the vaccine strain . All three European licensure criteria were met by adult subjects in response to the low-dose vaccine ; two criteria were met by the elderly age group  . Cross-reactive antibodies were detected against the heterologous A/H5N1 antigen strains A/Indonesia/05/05 and A/turkeyTurkey/01/05 . Both vaccines were generally well tolerated by both age groups . CONCLUSION These data demonstrate that a low antigen dose in combination with MF59 adjuvant is adequate for the routine pre-p and emic immunization of adult and elderly subjects Background The availability of H5N1 vaccines that can elicit a broad cross-protective immunity against different currently circulating clade 2 H5N1 viruses is a pre-requisite for the development of a successful pre-p and emic vaccination strategy . In this regard , it has recently been shown that adjuvantation of a recombinant clade 1 H5N1 inactivated split-virion vaccine with an oil-in-water emulsion-based adjuvant system also promoted cross-immunity against a recent clade 2 H5N1 isolate ( A/Indonesia/5/2005 , subclade 2.1 ) . Here we further analyse the cross-protective potential of the vaccine against two other recent clade 2 isolates ( A/turkey/Turkey/1/2005 and A/Anhui/1/2005 which are , as defined by WHO , representatives of subclades 2.2 and 2.3 respectively ) . Methods and Findings Two doses of the recombinant A/Vietnam/1194/2004 ( H5N1 , clade 1 ) vaccine were administered 21 days apart to volunteers aged 18–60 years . We studied the cross-clade immunogenicity of the lowest antigen dose ( 3.8 µg haemagglutinin ) given with ( N = 20 ) or without adjuvant ( N = 20 ) . Immune responses were assessed at 21 days following the first and second vaccine doses and at 6 months following first vaccination . Vaccination with two doses of 3.8 µg of the adjuvanted vaccine induced four-fold neutralising seroconversion rates in 85 % of subjects against A/turkey/Turkey/1/2005 ( subclade 2.2 ) and 75 % of subjects against A/Anhui/1/2005 ( subclade 2.3 ) recombinant strains . There was no response induced against these strains in the non-adjuvanted group . At 6 months following vaccination , 70 % and 60 % of subjects retained neutralising antibodies against the recombinant subclade 2.2 and 2.3 strains , respectively and 40 % of subjects retained antibodies against the recombinant subclade 2.1 A/Indonesia/5/2005 strain . Conclusions In addition to antigen dose-sparing , adjuvantation of inactivated split H5N1 vaccine promotes broad and persistent cross-clade immunity which is a pre-requisite for a pre-p and emic vaccine . Trial Registration Clinical Trials.gov The immunogenicity and lot-to-lot consistency of an AS03-adjuvanted H5N1 vaccine were evaluated in 1206 Asian adults , r and omised to receive two doses of adjuvanted ( 3.75 microg haemagglutinin ) or diluent-mixed vaccines , 21 days apart . Post-Dose 2 , 96.0 % of vaccinees in the H5N1-AS03 group demonstrated a four-fold increase in neutralising antibody titres against the vaccine strain A/Vietnam/1194/2004 and 91.4 % against strain A/Indonesia/05/2005 . Haemagglutination-inhibiting antibodies ( titre > or = 1:40 ) against A/Vietnam/1194/2004 and A/Indonesia/05/2005 strains were observed in 94.3 % and 50.2 % of subjects , respectively . Lot-to-lot consistency of the AS03-adjuvanted vaccine combinations was demonstrated . The AS03-adjuvanted vaccine was well tolerated , induced a high frequency of immune responses to the vaccine strain , allowed antigen sparing and promoted cross-clade immunity . These characteristics make it suitable for presumptive use if an H5N1 p and emic were considered to be imminent Proactive priming before the next p and emic could induce immune memory responses to novel influenza antigens . In an open-label study , we analyzed  B cell memory and antibody responses of 54 adults who received 2 7.5-μg doses of MF59-adjuvanted A/Vietnam/1194/2004 clade 1 ( H5N1 ) vaccine . Twenty-four subjects had been previously primed with MF59-adjuvanted or plain clade 0-like A/duck/Singapore/1997 ( H5N3 ) vaccine during 1999–2001 . The prevaccination frequency of circulating memory B cells reactive to A/Vietnam/1194/2004 was low in both primed and unprimed individuals . However , at day 21 after boosting , MF59-adjuvanted primed subjects displayed a higher frequency of H5N1-specific memory B cells than plain-primed or unprimed subjects . The immune memory was rapidly mobilized by a single vaccine administration and result ed in high titers of neutralizing antibodies to antigenically diverse clade 0 , 1 , and 2 H5N1 viruses already at day 7 . In general , postvaccination antibody titers were significantly higher in primed subjects than in unprimed subjects . Subjects primed with MF59-adjuvanted vaccine responded significantly better than those primed with plain vaccine , most notably in early induction and duration of cross-reacting antibody responses . After 6 months , high titers of cross-reactive antibody remained detectable among MF59-primed subjects . We conclude that distant priming with clade 0-like H5N3 induces a pool of cross-reactive memory B cells that can be boosted rapidly years afterward by a mismatched MF59-adjuvanted vaccine to generate high titers of cross-reactive neutralizing antibodies rapidly . These results suggest that pre-p and emic vaccination strategies should be considered Background . Accelerated immunization schedules may help gain early control of influenza p and emics . We investigated different schedules of an AS03A-adjuvanted H5N1 vaccine . Methods . This phase II , open-label , 6-month study r and omized participants ( aged 18–64 years ) to 2 vaccine doses administered 21 ( st and ard schedule ) , 14 , or 7 days apart , or on the same day . Co primary end points were that the lower limit of the 98.75 % confidence interval 14 days after the last dose must be ( 1 ) > 40 % for seroconversion rate ( SCR ) ( Center for Biologics Evaluation and Research [ CBER ] criterion ) and ( 2 ) > 50 % for seroprotection rate ( SPR ) ( attainment rate for reciprocal hemagglutination inhibition titers ≥40 , protocol -defined criterion ) for the vaccine homologous strain ( A/Indonesia/5/2005 ) . European Committee for Human Medicinal Products ( CHMP ) immunogenicity criteria were also evaluated . Results . Co primary end points were achieved ( lower 98.75 % confidence intervals exceeded defined values ) . Titers were highest with the st and ard schedule . Nevertheless , CBER SCR , protocol -defined SPR , and CHMP criteria were met with all schedules for the A/Indonesia/5/2005 strain . There were no significant differences between age groups ( 18–40 vs 41–64 years ) . Immune response was robust against drift variants A/turkey/Turkey/1/2005 and A/Vietnam/1194/2004 . Conclusions . The AS03A-adjuvanted H5N1 vaccine in accelerated schedules offers a robust immune response against vaccine homologous and drift variant strains , allowing consideration of compressed vaccination intervals . Clinical Trials Registration . NCT00695669 In an open label clinical study ( 2007 ) , MF59-adjuvanted hemagglutinin ( HA ) vaccine from H5N1-A/Vietnam/1194/2004 ( clade 1 ) was administered to subjects previously vaccinated ( primed ) with clade 0 H5N3 ( A/duck/Singapore/97 ) vaccine at least 6 years earlier ( in 1999 or 2001 ) . The primed individuals responded rapidly and generated high neutralizing antibody titers against the H5N1-Vietnam strain within 7 days of a single booster vaccination . Furthermore , significant cross-neutralization titers were measured against H5N1 clade 0 , 1 , and 2 viruses . In the current study , the impact of MF59 adjuvant during heterologous priming on the quality of humoral polyclonal immune response in different vaccine arms were further evaluated using real time kinetics assay by surface plasmon resonance ( SPR ) . Total anti-H5N1 HA1 polyclonal sera antibody binding from the heterologous prime-boost groups after a single MF59-H5N1 boost was significantly higher compared with sera from unprimed individuals that received two MF59-H5N1 vaccinations . The antigen-antibody complex dissociation rates ( surrogate for antibody affinity ) of the polyclonal sera against HA1 of H5N1-A/Vietnam/1194/2004 from the MF59-H5N3 primed groups were significantly higher compared to sera from unadjuvanted primed groups or unprimed individuals that received two MF59-H5N1 vaccines . Furthermore , strong inverse correlations were observed between the antibody dissociation off-rates of the immune sera against HA1 ( but not HA2 ) and the virus neutralization titers against H5 vaccine strains and heterologous H5N1 strains . These findings supports the use of oil-in-water-adjuvanted p and emic influenza vaccines to elicit long term memory B cells with high affinity BCR capable of responding to potential variant p and emic viruses likely to emerge and adapt to human transmissions Antigenically well-matched vaccines against highly pathogenic avian influenza H5N1 viruses are urgently required . Human serum sample s after immunization with MF59 or nonadjuvanted A/duck/Singapore/97 ( H5N3 ) vaccine were tested for antibody to 1997 - 2004 human H5N1 viruses . Antibody responses to 3 doses of nonadjuvanted vaccine were poor and were higher after MF59-adjuvanted vaccine , with seroconversion rates to A/HongKong/156/97 , A/HongKong/213/03 , A/Thail and /16/04 , and A/Vietnam/1203/04 of 100 % ( P < .0001 ) , 100 % ( P < .0001 ) , 71 % ( P = .0004 ) , and 43 % ( P = .0128 ) in 14 subjects , respectively , compared with 27 % , 27 % , 0 % , and 0 % in 11 who received nonadjuvanted vaccine . These findings have implication s for the rational design of p and emic vaccines against influenza H5 Background Promising clinical data and significant antigen-sparing have been demonstrated for a p and emic H5N1 influenza split-virion vaccine adjuvanted with AS03A , an α-tocopherol-containing oil-in-water emulsion-based Adjuvant System . Although studies using this formulation have been reported , there have been no data for Japanese population s. This study therefore aim ed to assess the immunogenicity and tolerability of a prep and emic ( H5N1 ) influenza vaccine adjuvanted with AS03A in Japanese adults . Methods This open-label , single-group study was conducted at two centres in Japan in healthy Japanese males and females aged 20 - 64 years ( n = 100 ) . Subjects received two doses of vaccine , containing 3.75 μg haemagglutinin of the A/Indonesia/5/2005-like IBCDC-RG2 Clade 2.1 ( H5N1 ) strain adjuvanted with AS03A , 21 days apart . The primary endpoint evaluated the humoral immune response in terms of H5N1 haemagglutination inhibition ( HI ) antibody titres against the vaccine strain ( Clade 2.1 ) 21 days after the second dose . Ninety five percent confidence intervals for geometric mean titres , seroprotection , seroconversion and seropositivity rates were calculated . Secondary and exploratory endpoints included the assessment of the humoral response in terms of neutralising antibody titres , the response against additional H5N1 strains ( Clade 1 and Clade 2.2 ) , as well as the evaluation of safety and reactogenicity . Results Robust immune responses were elicited after two doses of the prep and emic influenza vaccine adjuvanted with AS03A . Overall , vaccine HI seroconversion rates and seroprotection rates were 91 % 21 days after the second vaccination . This fulfilled all regulatory acceptance criteria for the vaccine-homologous HI antibody level . A substantial cross-reactive humoral immune response was also observed against the virus strains A/turkey/Turkey/1/2005 ( Clade 2.2 ) and A/Vietnam/1194/2004 ( Clade 1 ) after the second vaccine administration . A marked post-vaccination response in terms of neutralising antibody titres was demonstrated and persistence of the immune response was observed 6 months after the first dose . The vaccine was generally well tolerated and there were no serious adverse events reported . Conclusions The H5N1 c and i date vaccine adjuvanted with AS03A elicited a strong and persistent immune response against the vaccine strain A/Indonesia/5/2005 in Japanese adults . Vaccination with this formulation demonstrated a clinical ly acceptable reactogenicity profile and did not raise any safety concerns in this population .Trial registration Clinical trials.gov Please cite this paper as : Gillard et al. ( 2012 ) An assessment of prime‐boost vaccination schedules with AS03A‐adjuvanted prep and emic H5N1 vaccines : a r and omized study in European adults . Influenza and Other Respiratory Viruses DOI : 10.1111/j.1750‐2659.2012.00349.x . Background Long‐term persistence of immune response and safety of an H5N1 prep and emic influenza vaccine adjuvanted with AS03 ( an α‐tocopherol oil‐in‐water emulsion‐based adjuvant system ) was evaluated using various prime‐boost schedules that mimicked potential p and emic scenarios ( NCT00430521 ) . Methods Five hundred and twelve healthy adults aged 18–60 years received primary vaccination with one or two doses ( 0 , 21 days schedule ) of the A/Vietnam/1194/2004 H5N1 vaccine followed by a booster dose ( A/Vietnam/1194/2004 or A/Indonesia/05/2005 strain ) six or twelve months later across eight r and omized groups . Immunogenicity results by hemagglutination inhibition [ HI ] assay , microneutralization assay , and the cell‐mediated immune response ( CMI ) are reported here for the four groups boosted at Month 12 . Results A one‐dose‐adjuvanted primary administration followed 12 months later by a single‐adjuvanted booster dose containing a heterologous vaccine strain met or exceeded all US and European criteria for both strains . Increasing the interval between the first and second dose ( from 21 days to 12 months ) result ed in stronger cross‐reactive immune responses against the A/Indonesia/05/2005 strain . The HI antibody response against the two strains persisted for 6 months after the booster dose irrespective of the booster vaccine ’s strain . The neutralizing antibody responses and the CMI observed in the study population paralleled the HI immune response . Overall , the vaccine had a clinical ly acceptable safety profile . Conclusion The H5N1 vaccine in this study allowed for flexibility in the time interval between primary and booster vaccination and the use of a heterologous strain without impacting the strength of the humoral and cellular immune response to both vaccine strains An influenza vaccine with cross-immunogenic potential could play a key role in p and emic mitigation by promoting a rapid immune response to infection and /or subsequent vaccination with strains drifted from the primary vaccine strain . Here we assess the role of AS03(A ) ( an oil-in-water emulsion based Adjuvant System containing tocopherol ) in this prime-boost concept using H5N1 as a model shift influenza antigen . In this open , non-r and omised study ( NCT00506350 ; an extension of an earlier r and omised study ) we assessed immunogenicity in nine groups of 35 - 50 volunteers aged 19 - 61 years following administration of AS03(A)-adjuvanted split-virion H5N1 vaccine containing 3.75mug of haemagglutinin ( HA ) from the A/Indonesia/5/2005(IBCDC-RG2 ) clade 2.1 strain . A single booster dose of vaccine was administered to four groups primed 14 months previously with different HA levels of AS03(A)-adjuvanted clade 1 A/Vietnam/1194/2004 H5N1 vaccine . Two booster doses ( given 21 days apart ) were administered to four groups primed 14 months previously with different HA levels of non-adjuvanted A/Vietnam/1194/2004 H5N1 vaccine and also to a control group of un-primed subjects . In individuals primed 14 months earlier with AS03(A)-adjuvanted A/Vietnam/1194/2004 vaccines , a single booster dose of AS03(A)-adjuvanted A/Indonesia/5/2005 induced rapid immune responses ( licensure criteria met in 7 - 14 days ) comparable to that observed in the un-primed control group following two doses of adjuvanted vaccine . In contrast , individuals primed with non-adjuvanted formulations exhibited minimal immune responses which , even after two doses , were unexpectedly much lower than that observed in un-primed subjects . AS03(A ) enhances the initial priming effect of p and emic influenza vaccination enabling a rapid humoral response to single dose boosting with a heterologous strain at 14 months . In contrast , priming without adjuvant appears to inhibit the response to subsequent vaccination with a heterologous strain . These findings should guide the development of vaccines to combat the present influenza A/H1N1 p and emic Priming a population with a pre-p and emic vaccine  is being considered to maximize the response upon subsequent vaccination with a true p and emic vaccine more closely matched to the causative p and emic strain . The present study explored this prime-boost concept by evaluating different primary schedules with the pre-p and emic A/Vietnam/1194/2004(NIBRG-14 ) vaccine , containing 3.75 microg of HA , followed by a 6-month booster with a vaccine formulated with 3.75 microg HA of either the same strain or with A/Indonesia/05/2005(IBCDC-RG2 ) , a heterologous strain from a different clade . In this multicentre , open , r and omized study ( NCT00430521 ) we measured immune responses in four groups ( N = 48 - 60 ) of adults aged 18 - 60 years who received a single booster administration of either A/Indonesia/05/2005 or A/Vietnam/1194/2004 vaccine 6 months after a 1- or 2-dose ( given 21 days apart ) primary vaccination with A/Vietnam/1194/2004 .  All prime-boost schedules assessed induced early ( 7 days post-booster ) humoral responses that met regulatory acceptance criteria . Two doses of A/Vietnam/1194/2004 given 6 months apart achieved equivalent homologous seroprotection after the second vaccination ( 89.6 % ) , when compared to two doses given 21 days apart ( 92.7 - 93.2 % ) . Remarkably , two doses of A/Vietnam/1194/2004 given 6 months apart induced a higher cross-reactive seroprotection against A/Indonesia/05/2005 ( 83.3 % ) when compared to two doses given 21 days apart ( 41.5 - 54.5 % ) . A 6-month A/Indonesia/05/2005 booster dose after one primary dose of A/Vietnam/1194/2004 vaccine induced 92.5 % seroprotection against A/Indonesia/05/2005 and 98.1 % against A/Vietnam/1194/2004 . Since a single booster 6 months after one primary dose of AS03-adjuvanted vaccine induces strong and rapid seroprotective immune response against both homologous and heterologous H5N1 strains , these results might have important implication s for public health strategy aim ing to organize vaccination campaigns with pre-p and emic vaccines Background : The development of vaccines against p and emic influenza viruses for use in children is a public health priority . Methods : In this phase II , r and omized , open study , the immunogenicity and reactogenicity of H5N1 A/Vietnam/1194/2004 ( NIBRG-14 ) ( clade 1 ) prep and emic influenza vaccine were assessed in children aged 3 to 5 and 6 to 9 years . Children were r and omized to receive 2 doses , given 21 days apart , of A/Vietnam/1194/2004 vaccine containing 1.9 & mgr;g or 3.75 & mgr;g hemagglutinin antigen ( HA ) , adjuvanted with a tocopherol-based oil-in-water emulsion ( AS03 ) containing 11.86 mg ( AS03A ) or 5.93 mg ( AS03B ) tocopherol . Control groups received 2 doses of trivalent influenza vaccine ( TIV ) .  Humoral immune responses , reactogenicity , and safety were the primary outcome measures ; cross-reactivity and cell-mediated responses were also assessed ( NCT00502593 ) . Results : Between 49 and 51 children in each age stratum ( aged 3–5 and 6–9 years ) received H5N1 vaccine , and between 17 and 18 children in each age stratum received TIV . After the second dose , recipients of H5N1 vaccine ( 1.9 & mgr;g HA/AS03B , 3.75 & mgr;g HA/AS03B , and 3.75 & mgr;g HA/AS03A ) achieved humoral antibody titers against the vaccine-homologous strain , which fulfilled the United States influenza vaccines licensure criteria for immunogenicity . With the exception of 1 child , there were no H5N1 immune responses in children who received TIV . The most frequent injection-site event was pain in all groups , and the H5N1 vaccine had a clinical ly acceptable reactogenicity and safety profile . Exploratory analyses in children aged 3 to 5 years indicated that the induction of CD4 + T-cell responses polarized in favor of a T-helper 1 profile . Conclusions : The results showed that 2 doses of AS03-adjuvanted H5N1 influenza vaccine at antigen-sparing doses of 1.9 & mgr;g or 3.75 & mgr;g HA elicited broad and persistent immune responses with acceptable reactogenicity , and without safety concerns , in children aged 3 to 9 years BACKGROUND The tocopherol-based oil-in-water emulsion adjuvant system family ( AS03 ) improves antigen sparing with split-virion H5N1 influenza vaccines , representing an important development for p and emic preparedness . In this phase 1/2 r and omized , controlled , observer-blinded study in 680 adults , we assessed the immunogenicity and safety of  A/Indonesia/5/05 H5N1 ( IBCDC-RG2 , clade 2.1 )  prep and emic c and i date vaccines produced at 2 separate manufacturing sites . METHODS Two doses , each of which contained 3.75 microg of hemagglutinin antigen , were given 21 days apart either without adjuvant or with an adjuvant system containing 11.86 mg or 5.93 mg of tocopherol ( AS03 ) . RESULTS The AS03-adjuvanted A/Indonesia/05/2005 ( NIBRG-14 ) vaccines were significantly more immunogenic than nonadjuvanted vaccine in homologous assays . Neutralizing cross-clade immunogenicity against clades 1 , 2.2 , and 2.3 was demonstrated at day 42 with all vaccines ; at 6 months , seroconversion rates were highest for clade 2.2 ( 60.7 % ) and for clade 1 ( 38.3 % ) . Adjuvantation was associated with increased short-term injection-site reactions ( pain ) in 80 % of participants , with such reactions assessed as being of grade 3 severity for 4.0 % of doses . No other safety or reactogenicity concerns were identified over 6 months of follow-up . CONCLUSIONS Humoral responses against the adjuvanted 3.75-microg hemagglutinin antigen vaccines from both manufacturing sites fulfilled European and US licensure criteria for immunogenicity for influenza vaccines Background Pathogenic avian influenza virus ( H5N1 ) has the potential to cause a major global p and emic in humans . Safe and effective vaccines that induce immunologic memory and broad heterotypic response are needed . Methods and Findings Healthy adults aged 18–60 and > 60 years ( n = 313 and n = 173 , respectively ) were r and omized ( 1∶1 ) to receive two primary and one booster injection of 7.5 μg or 15 μg doses of a subunit MF59-adjuvanted H5N1 ( A/Vietnam/1194/2004 ) ( clade 1 ) vaccine . Safety was monitored until 6 months after booster . Immunogenicity was assessed by hemagglutination inhibition ( HI ) , single radial hemolysis ( SRH ) and microneutralization assays ( MN ) . Mild injection-site pain was the most common adverse reaction . No serious adverse events relating to the vaccine were reported . The humoral immune responses to 7.5 μg and 15 μg doses were comparable . The rates for seroprotection ( HI>40 ; SRH>25mm2 ; MN ≥40 ) after the primary vaccination ranged 72–87 % . Six months after primary vaccination with the 7.5 μg dose , 18 % and 21 % of non-elderly and elderly adults were seroprotected ; rates increased to 90 % and 84 % , respectively , after the booster vaccination . In the 15 μg group , seroprotection rates among non-elderly and elderly adults increased from 25 % and 62 % after primary vaccination to 92 % and 88 % after booster vaccination , respectively . A heterologous immune response to the H5N1/turkey/Turkey/05 strain was elicited after second and booster vaccinations . Conclusions Both formulations of MF59-adjuvanted influenza H5N1 vaccine were well tolerated . The European Union requirement for licensure for pre-p and emic vaccines was met by the lower dose tested . The presence of cross-reactive antibodies to a clade 2 heterologous strain demonstrates that this vaccine may be appropriate for pre-p and emic programs . Trial Registration Clinical Trials.gov The st and ard serological methods present limitations for the measurement of immunity against H5N1 influenza strains . The hemagglutination inhibition ( HI ) assay lacks sensitivity and requires st and ardization , while the viral micro-neutralization ( MN ) assay needs h and ling of live virus . We produced pseudoparticles expressing hemagglutinin from clades 1 or 2 H5N1 in order to measure neutralizing antibodies in human sera after prime-boost vaccination with plain or MF59-adjuvanted H5N1 clade 1 subunit vaccines . Titers measured by pseudoparticle neutralization ( PPN ) assay significantly correlated with those measured by HI , single radial haemolysis or MN , with a PPN titer of 1:357 corresponding to an MN titer of 1:80 . Notably , results from the PPN assay , confirm that MF59-H5N1 vaccine induces potent and long-lasting neutralizing antibody responses not only against the vaccine strain , but also against several heterologous clade 2 strains . Overall , the PPN assay represents a valid alternative to conventional serological methods for the evaluation of H5N1 vaccine immunogenicity BACKGROUND H7 influenza strains can cause severe and often fatal human infections , especially in the elderly . This phase II , observer-blind , r and omized trial ( www . Clinical Trials.gov : NCT01949090 ) assessed the immunogenicity and safety of a novel AS03-adjuvanted H7N1 vaccine that may serve as a model H7-subtype vaccine . METHODS 360 adults ≥65years of age in stable health received either 1 of 4 adjuvanted A/mallard/Netherl and s/12/2000 split virion vaccine formulations ( 3.75μg or 7.5μg hemagglutinin adjuvanted with either AS03A or AS03B ) or saline placebo , given as a 2-dose series . Immunogenicity was assessed using hemagglutination-inhibition ( HI ) and microneutralization ( MN ) assays for the per- protocol cohort , comprising 332 participants at 21days post-each dose , 332 at month 6 , and 309 at month 12 ( HI assay only ) . Safety was assessed up to month 12 for all participants who had received ≥1 dose ( 360 participants ) . RESULTS For H7N1 HI antibody assessment at day 42 ( 21days post-dose 2 ) , seroprotection rates ( SPR ) in the vaccinated groups were 69.6%-88.7 % , seroconversion rates ( SCR ) 69.6%-88.5 % , mean geometric increase ( MGI ) 11.0 - 18.9 , and HI geometric mean titers ( GMTs ) 55.0 - 104.8 . These parameters declined by month 6 and month 12 . Microneutralization GMTs were 46.2 - 74.7 in the vaccinated groups at day 42 , while vaccine response rate ( VRR ; proportion with ≥4-fold increase in MN titer ) was 46.4%-81.5 % . For the cross-reactive H7N9 strain , at day 42 , HI GMT were 64.3 - 201.3 , SPR 78.6%-96.3 % , SCR 79.3%-96.3 % , and MGI 14.1 - 37.7 ; MN GMTs were 44.0 - 85.6 , and VRR 46.4 - 85.2 % . The most frequent solicited symptom was injection site pain ( 41.7%-65.0 % of vaccine recipients ) . In total , 40 participants reported 67 serious adverse events ; none were considered causally related to vaccination . CONCLUSIONS In adults aged ≥65years , the adjuvanted H7N1 vaccine was immunogenic after 2 doses , and had an acceptable safety profile . www . Clinical Trials.gov : NCT01949090 BACKGROUND Preparedness for an H5N1 influenza pre-p and emic requires effective and well-tolerated emergency vaccination strategies that provide both p and emic strain-specific and heterologous protection . OBJECTIVES This was a pivotal study for the regulatory approval process for a c and i date MF59-adjuvanted H5N1 vaccine . Its goals were to identify the preferred primary 2-dose vaccination schedule in adults and to assess whether the vaccine met European Committee for Medicinal Products for Human Use ( CHMP ) licensure criteria . METHODS Healthy volunteers aged 18 to 60 years received 1 of 4 r and omized  schedules in which the 2 doses of vaccine were separated by a 1- , 2- , 3- , or 6-week interval . Three blood sample s ( ~20 mL(-1 ) ) were obtained from each subject : the first sample , immediately before administration of the first dose of vaccine ; the second , immediately before administration of the second dose ; and the third , 21 days after administration of the second dose . Hemagglutination inhibition ( HI ) , microneutralization ( MN ) , and single radial hemolysis ( SRH ) were assayed after each dose . Immunogenicity was assessed based on the CHMP licensure criteria for annual influenza vaccines ( number of seroconversions or significant increase in HI titer > 40 % ; mean geometric increase > 2.5 ; and proportion of subjects achieving an HI titer ≥40 or SRH titer > 25 mm(2 ) should be > 70 % [ seroprotection ] ) . Subjects recorded all adverse events occurring within 7 days of vaccine administration ; information on any serious adverse events was collected throughout the study ( duration , 202 days ) . RESULTS All study participants ( N = 240 ) were white , with a mean age of 33 years and a mean body mass index of 24.6 kg/m(2 ) . Equal numbers of men and women were assigned to each vaccination schedule . The CHMP criterion for seroprotection was achieved when the 2 doses of vaccine were separated by 2 ( 76 % ) , 3 ( 72 % ) , and 6 ( 79 % ) weeks ; similar results were obtained on MN and SRH analysis . On the SRH analysis , the c and i date vaccine showed a heterologous immune response to the H5N1/turkey/Turkey/1/05 ( NIBRG-23 ; clade 2 ) influenza antigen . The vaccine met 2 of the 3 European licensure criteria , with seroconversion rates of 69 % and 65 % in the groups assigned to a 2- and 3-week interval between doses , respectively , and geometric mean ratios of 4.3 and 4.5 . There were no serious adverse events related to vaccination . The most common adverse events reported within 7 days of the first and second doses of vaccine were mild to moderate injection-site pain ( 63%-73 % and 34%-48 % , respectively ) and fatigue ( 25%-30 % and 13%-24 % ) . CONCLUSIONS Two 7.5-μg doses of MF59-adjuvanted H5N1 influenza vaccine given 2 , 3 , or 6 weeks apart afforded H5N1-specific immunity and met the CHMP licensure criterion for seroprotection in these healthy volunteers . Clinical ly relevant levels of heterologous immunity were observed when the 2 doses of vaccine were administered either 2 or 3 weeks apart ; however , the licensure criterion for seroprotection was not met in this case BACKGROUND / PURPOSE This study evaluated the immune response elicited by two formulations of an AS03(A)-adjuvanted H5N1 A/Indonesia/05/2005 prep and emic influenza vaccine , developed using manufacturing processes with or without thiomersal . In addition , it also evaluated compliance to the Centre for Biologics Evaluation and Research and Committee for Medicinal Products for Human Use ( CHMP ) immunogenicity guidance criteria for p and emic influenza vaccines in adults . METHODS This phase III , observer-blind , r and omized study ( NCT00812981 ) enrolled 320 subjects aged 18 - 60 years into two groups to receive , 21 days apart , two doses of the formulation manufactured using either the thiomersal-containing process ( Group TC ) or the thiomersal-free process ( Group TF ) . Blood sample s collected before vaccination , 21 days after the second vaccine dose , and 6 months following the first vaccine dose ( Days 0 , 42 , and 180 ) were analysed using a hemagglutination inhibition ( HI ) assay . Safety assessment s were made for the entire study period . RESULTS Twenty-one days after the second dose of vaccine , both groups met the CHMP criteria for vaccine-homologous HI response ( seroprotection rates/seroconversion rates ≥ 98.7 % , seroconversion factor ≥ 121.9 ) and also for a heterologous HI response against the A/Vietnam/1194/2004 strain ( seroprotection rates/seroconversion rates ≥ 81.3 % , seroconversion factor ≥ 10.8 ) . Six months after the first dose of vaccine , a marked persistence of the vaccine-homologous HI response was observed that still met one or more CHMP criteria . Pain at the injection site ( Group TF 95 % , Group TC 91.8 % ) and myalgia ( Group TF 68.8 % , Group TC 63.5 % ) were the most frequently recorded solicited symptoms . Overall , both formulations had a clinical ly acceptable safety profile . CONCLUSION Administration of two doses of the AS03(A)-adjuvanted H5N1 prep and emic influenza vaccine was found to be highly immunogenic in adults with a clinical ly acceptable safety profile . The ability to confer cross-clade protective immunity makes it a suitable option for mitigation of the morbidity and mortality of outbreaks and p and emics due to H5N1 and drifted strains
BACKGROUND Cross-clade immunogenic stockpiled H5N1 vaccines may decrease the morbidity and transmission of infection during the initial phase of influenza p and emic .
Meta- analysis of cross-reactive antibodies induced by oil-in-water emulsion adjuvanted ( OWEA ) influenza H5N1 virus monovalent vaccines with circulating heterologous H5N1 virus strains , isolated from human infections was performed .