A randomised, single-blind, dose-range study to assess the immunogenicity and safety of a cell-culture-derived A/H1N1 influenza vaccine in adult and elderly populations.

BACKGROUND: Modern cell-culture production techniques and the use of adjuvants helps to ensure that the global demand for pandemic influenza vaccine can be met. This study aimed to assess the immunogenicty and safety profiles of various cell-culture-derived A/H1N1 pandemic vaccine formulations in healthy adult and elderly subjects. METHODS: Adult (18-60 years) subjects (n=544) received vaccine either containing 3.75 µg of antigen with half the standard dose of MF59 (Novartis Vaccines and Diagnostics) adjuvant, 7.5 µg antigen with a full dose of MF59, or a non-adjuvanted vaccine containing 15 µg of antigen. Elderly (≥ 61 years) subjects (n=268) received either the 3.75 µg or 7.5 µg adjuvanted formulations. Two priming vaccine doses were administered 3 weeks apart, followed by a single booster dose of seasonal influenza vaccine 1 year later. Immunogenicity was assessed 3 weeks after each vaccination. The safety profile of each formulation was evaluated throughout the study. RESULTS: A single primary dose of each A/H1N1 vaccine formulation was sufficient to meet all three European (CHMP) licensure criteria for pandemic influenza vaccines in adult subjects. Two licensure criteria were met after one vaccine dose in elderly subjects; two primary doses were required to meet all three criteria in this age group. The highest antibody titres were observed in response to the 7.5 µg vaccine containing a full dose of MF59 adjuvant. All subjects rapidly generated seroprotective antibody titres in response to booster vaccination. CONCLUSION: This study identified one 3.75 µg vaccine dose containing half the standard dose of MF59 adjuvant as optimal for adults, two doses were optimal for elderly subjects. The antigen-sparing properties of MF59, and rapid, modern, cell-culture production techniques represent significant steps towards meeting the global demand for influenza vaccine.

Immunogenicity, safety and reactogenicity of a mammalian cell-culture-derived influenza vaccine in healthy children and adolescents three to seventeen years of age.

BACKGROUND: The safety and immunogenicity of the cell-culture-derived seasonal trivalent influenza vaccine ([CCIV]; Optaflu) has been reported previously in adults and the elderly. In this study, we compared the safety, reactogenicity and immunogenicity of CCIV with a conventional egg-derived trivalent influenza vaccine (TIV) in a healthy pediatric population. METHODS: A total of 3604 subjects were randomized to receive 2 doses of CCIV or TIV (3-8 years, n = 2630) at a 28-day interval or a single vaccination (9-17 years, n = 974). Antibody levels on days 1, 29 and 50 were measured by hemaglutination inhibition assay using egg-derived and cell-derived test antigens. Adverse reactions were solicited via memory aids for 7 days after each injection, and unsolicited adverse events/serious adverse events were collected for 6 months postvaccination. RESULTS: Noninferiority of CCIV versus TIV was demonstrated for most immunogenicity measures, particularly by using cell-derived antigen in the hemaglutination inhibition assay. In 3- to 8-year-olds (the primary objective), both CCIV and TIV met all 3 Committee for Medicinal Products for Human Use immunogenicity criteria for A/H1N1 and A/H3N2 strains. Lower immune responses were observed against the B strain, fulfilling Committee for Medicinal Products for Human Use criteria only for geometric mean ratio (TIV, CCIV) and seroconversion rate (TIV, CCIV [cell-derived antigen]). Both CCIV and TIV were safe and well tolerated, with no differences in local and systemic solicited reactions or in unsolicited adverse events/serious adverse events. CONCLUSION: CCIV produced in mammalian cell culture is a safe, well-tolerated and immunogenic alternative to conventional egg-derived influenza vaccines for children and adolescents.

Safety, immunogenicity and dose ranging of a new Vi-CRM197 conjugate vaccine against typhoid fever: randomized clinical testing in healthy adults.

BACKGROUND: Typhoid fever causes more than 21 million cases of disease and 200,000 deaths yearly worldwide, with more than 90% of the disease burden being reported from Asia. Epidemiological data show high disease incidence in young children and suggest that immunization programs should target children below two years of age: this is not possible with available vaccines. The Novartis Vaccines Institute for Global Health developed a conjugate vaccine (Vi-CRM197) for infant vaccination concomitantly with EPI vaccines, either starting at 6 weeks with DTP or at 9 months with measles vaccine. We report the results from a Phase 1 and a Phase 2 dose ranging trial with Vi-CRM197 in European adults. METHODOLOGY: Following randomized blinded comparison of single vaccination with either Vi-CRM197 or licensed polysaccharide vaccines (both containing 25·0 µg of Vi antigen), a randomised observer blinded dose ranging trial was performed in the same center to compare three concentrations of Vi-CRM197 (1·25 µg, 5·0 µg and 12·5 µg of Vi antigen) with the polysaccharide vaccine. PRINCIPAL FINDINGS: All vaccines were well tolerated. Compared to the polysaccharide vaccine, Vi-CRM197 induced a higher incidence of mild to moderate short lasting local pain. All Vi-CRM197 formulations induced higher Vi antibody levels compared to licensed control, with clear dose response relationship. CONCLUSIONS: Vi-CRM197 did not elicit safety concerns, was highly immunogenic and is therefore suitable for further clinical testing in endemic populations of South Asia. TRIAL REGISTRATION: ClinicalTrials.gov NCT01123941 NCT01193907.

MF59 adjuvant enhances diversity and affinity of antibody-mediated immune response to pandemic influenza vaccines.

Oil-in-water adjuvants have been shown to improve immune responses against pandemic influenza vaccines as well as reduce the effective vaccine dose, increasing the number of doses available to meet global vaccine demand. Here, we use genome fragment phage display libraries and surface plasmon resonance to elucidate the effects of MF59 on the quantity, diversity, specificity, and affinity maturation of human antibody responses to the swine-origin H1N1 vaccine in different age groups. In adults and children, MF59 selectively enhanced antibody responses to the hemagglutinin 1 (HA1) globular head relative to the more conserved HA2 domain in terms of increased antibody titers as well as a more diverse antibody epitope repertoire. Antibody affinity, as inferred by greatly diminished (≥10-fold) off-rate constants, was significantly increased in toddlers and children who received the MF59-adjuvanted vaccine. Moreover, MF59 also improved antibody affinity maturation after each sequential vaccination against avian H5N1 in adults. For both pandemic influenza vaccines, there was a close correlation between serum antibody affinity and virus-neutralizing capacity. Thus, MF59 quantitatively and qualitatively enhances functional antibody responses to HA-based vaccines by improving both epitope breadth and binding affinity, demonstrating the added value of such adjuvants for influenza vaccines.

Immunogenicity and reactogenicity of a combined fully liquid DTPw-HepB-Hib pentavalent vaccine in healthy infants: no clinically relevant impact of a birth dose of hepatitis B vaccine.

OBJECTIVES: In this open-label, non-randomized phase II study, the safety and immunogenicity of a fully liquid diphtheria-tetanus-whole cell pertussis-hepatitis B-Haemophilus influenzae type b (DTPw-HepB-Hib) combination vaccine (Quinvaxem(®)) were assessed in infants who had or had not received a birth dose of hepatitis B (HepB) vaccine. STUDY DESIGN: Two groups of infants, 'HepB at birth' (n=110) and 'no HepB at birth' (n=108), were enrolled and received a primary vaccination course using a 2-4-6 months schedule. RESULTS: Seroprotection/seroconversion rates of >95% were achieved against all antigens included in the combination vaccine for both study groups. Although significantly higher anti-hepatitis B virus (p<0.001) and anti-tetanus (p=0.031) antibody titers were achieved in group 'HepB at birth' when compared with group 'no HepB at birth', the proportion of 'no HepB at birth' subjects achieving protective titers was non-inferior to the proportion of subjects in group 'HepB at birth'. The birth dose of HepB vaccine did not seem to influence the safety pattern of the DTPw-HepB-Hib combination vaccine. CONCLUSIONS: The present study demonstrated that the fully liquid DTPw-HepB-Hib vaccine was safe and immunogenic when administered using a 2-4-6 months immunization schedule, regardless of whether or not infants had received a dose of HepB vaccine at birth.

A fully liquid DTPw-HepB-Hib combination vaccine for booster vaccination of toddlers in El Salvador.

OBJECTIVES: To compare the safety and immunogenicity of a booster dose of a fully liquid diphtheria-tetanus-whole cell pertussis-hepatitis B-Haemophilus influenzae type b (DTPw-HepB-Hib) vaccine to the separate administration of commercially available DTPw and Hib vaccines in healthy toddlers. METHODS: An open-label, randomized, parallel-group, Phase III study conducted at six centers in San Salvador, El Salvador, during February-June 2006. Toddlers (15-24 months of age) were eligible to participate if they had received primary immunization at 2, 4, and 6 months of age with a commercial DTPw-HepB/Hib vaccine requiring reconstitution. Participants received either one booster dose of DTPw-HepB-Hib fully liquid vaccine or DTPw and Hib vaccines administered separately. Blood samples were taken immediately prior to and at 1 month post-vaccination. For a 5-day period following vaccination, solicited adverse events were collected in subject diaries and assessed. RESULTS: The combined DTPw-HepB-Hib fully liquid vaccine was non-inferior to the separately administered DTPw and Hib vaccines, in terms of seroprotection/seroconversion rates for all antigens evaluated. The combination vaccine elicited a strong booster response as demonstrated by a large increase in antibodies against all vaccine antigens. The geometric mean concentrations (GMCs) of all antibodies in the DTPw-HepB-Hib group exceeded the seroprotection/seroconversion thresholds by very large margins, although for some antigens they were somewhat lower than the corresponding titers in the comparator group. With the combination vaccine, considerably fewer solicited local and systemic adverse events, such as fever and irritability, were reported than with the comparator vaccines. CONCLUSIONS: This study demonstrates that the fully liquid combined DTPw-HepB-Hib vaccine is highly immunogenic and has a favorable safety profile when given as a booster vaccination to toddlers who have received a primary vaccination course with a different pentavalent vaccine that requires reconstitution.

A fully liquid DTPw-HepB-Hib combination vaccine for booster vaccination of toddlers in El Salvador / Vacuna líquida combinada DTPw-HepB-Hib como dosis de refuerzo en infantes de El Salvador

Objectives:To compare the safety and immunogenicity of a booster dose of a fully liquid diphtheria-tetanus-whole cell pertussis-hepatitis B-Haemophilus influenzae type b (DTPw-HepB-Hib) vaccine to the separate administration of commercially available DTPw and Hib vaccines in healthy toddlers. Methods:An open-label, randomized, parallel-group, Phase III study conducted at six centers in San Salvador, El Salvador, during February-June 2006. Toddlers (15-24 months of age) were eligible to participate if they had received primary immunization at 2, 4, and 6 months of age with a commercial DTPw-HepB/Hib vaccine requiring reconstitution. Participants received either one booster dose of DTPw-HepB-Hib fully liquid vaccine or DTPw and Hib vaccines administered separately. Blood samples were taken immediately prior to and at 1 month post-vaccination. For a 5-day period following vaccination, solicited adverse events were collected in subject diaries and assessed. Results:The combined DTPw-HepB-Hib fully liquid vaccine was non-inferior to the separately administered DTPw and Hib vaccines, in terms of seroprotection/seroconversion rates for all antigens evaluated. The combination vaccine elicited a strong booster response as demonstrated by a large increase in antibodies against all vaccine antigens. The geometric mean concentrations (GMCs) of all antibodies in the DTPw-HepB-Hib group exceeded the seroprotection/seroconversion thresholds by very large margins, although for some antigens they were somewhat lower than the corresponding titers in the comparator group. With the combination vaccine, considerably fewer solicited local and systemic adverse events, such as fever and irritability, were reported than with the comparator vaccines. Conclusions:This study demonstrates that the fully liquid combined DTPw-HepB-Hib vaccine is highly immunogenic and has a favorable safety profile when given as a booster vaccination to toddlers who have received...

Objetivos:Comparar la seguridad y la inmunogenicidad en infantes saludables de una dosis de refuerzo de una vacuna líquida combinada contra la difteria, el tétanos, la tosferina (de células enteras), la hepatitis B y Haemophilus influenzae tipo b (DTPw-HepB-Hib), con la aplicación por separado de vacunas DTPw y Hib disponibles comercialmente. Métodos:Se realizó un estudio de fase III abierto, aleatorizado, con grupos paralelos, en seis centros de San Salvador, El Salvador, en febrero-junio de 2006. Los infantes (de 15-24 meses) habían recibido la inmunización primaria a los 2, 4 y 6 meses de edad con una vacuna comercial DTPw-HepB/Hib que necesitaba reconstitución. Los lactantes recibieron una dosis de refuerzo con la vacuna DTPw-HepB-Hib o las vacunas DTPw y Hib por separado. Se tomaron muestras de sangre inmediatamente antes de la vacunación y un mes después. Las reacciones adversas en los cinco días siguientes a la vacunación se anotaron en diarios individuales y se evaluaron. Resultados:Según las tasas de seroprotección/seroconversión de todos los antígenos evaluados, la vacuna DTPw-HepB-Hib no fue inferior que las vacunas DTPw y Hib administradas por separado. La vacuna combinada produjo una fuerte respuesta de refuerzo, reflejada en el gran aumento de anticuerpos contra todos los antígenos presentes. Con respecto al grupo de comparación, en el grupo vacunado con DTPw-HepB-Hib las concentraciones geométricas medias de todos los anticuerpos superaron ampliamente los umbrales de seroprotección/seroconversión -aunque con títulos menores en algunos antígenos- y hubo mucho menos reacciones adversas locales y sistémicas, como fiebre e irritabilidad. Conclusiones:Se demostró que la vacuna líquida combinada DTPw-HepB-Hib es altamente inmunógena y satisfactoriamente segura cuando se aplica como dosis de refuerzo a infantes inmunizados primariamente con una vacuna pentavalente diferente que requiere reconstitución.

Dose ranging of adjuvant and antigen in a cell culture H5N1 influenza vaccine: safety and immunogenicity of a phase 1/2 clinical trial.

BACKGROUND: Dose-sparing strategies and new production technologies will be necessary to produce adequate supplies of vaccines for pandemic influenza. One approach is to include adjuvant, which can reduce the amount of antigen required for immunization and stimulate cross-reactive responses to drifted variants of novel viruses. Dose-sparing studies of adjuvant, itself a finite resource, have not previously been reported for H5N1 vaccine development. METHODOLOGY/PRINCIPAL FINDINGS: A total of 753 healthy 18-40-year-old adults were randomized to one of 12 groups (N approximately 60/group) to receive two intramuscular doses, 21 days apart, of 3.75, 7.5 or 15 microg of cell culture grown influenza A/H5N1 hemagglutinin (A/Indonesia/5/2005 (H5N1)/PR-8-IBCDC-RG2), each dose level formulated with 0%, 25%, 50% or 100% of the MF59 dose contained in licensed influenza vaccine. 752 subjects actually received one dose, and 695 a second dose. Serum hemagglutination inhibition and neutralizing antibody levels, were determined before and 21 days after each dose. Safety and reactogenicity were assessed by self-completed diary cards. Nonadjuvanted H5N1 formulations were poorly immunogenic, but antibody responses were significantly enhanced by all doses of MF59 for each antigen level. The 3.75 microg H5N1 containing 50% MF59 satisfied the European criteria for pandemic vaccine licensure. All formulations were well tolerated, although MF59 dose-dependent increases in the frequency of injection site pain were observed. The frequencies of injection site and systemic reactions were lower after receipt of the second dose of vaccine. No vaccine-related SAE was reported. CONCLUSIONS: Dose-sparing of both antigen and adjuvant is possible without compromising immunogenicity, while improving reactogenicity and is a promising strategy that will expand the availability of vaccines for global control of pandemic influenza.

Safety and immunogenicity of a novel influenza subunit vaccine produced in mammalian cell culture.

BACKGROUND: Immunization remains the best prevention strategy for influenza, but production constraints for egg-based influenza vaccines have prompted the development of innovative cell culture manufacturing processes. Here, we describe a novel cell culture-derived influenza vaccine (CCIV) produced in Madin-Darby canine kidney cells. METHODS: This phase 3, observer-blind, randomized, multicenter study in Poland compared the immunogenicity of a CCIV and a conventional egg-based vaccine. Participants, stratified by age (adults 18-60 years, n = 1300; elderly persons > or = 61 years, n = 1354), received a single intramuscular vaccination. Immunogenicity was assessed 21 days later by hemagglutination inhibition assay. Reactogenicity was assessed using self-completed diary cards. RESULTS: The immunogenicity of CCIV was noninferior to that of the conventional vaccine for all 3 vaccine strains in both age groups, regardless of underlying health status. Both vaccines fulfilled European Union registration criteria and were well tolerated, with similar incidences of solicited local and systemic reactions in both age groups; the only significant difference was an increased frequency of mild or moderate pain with CCIV than the conventional vaccine among adult (22% vs 17%; P < .05) and elderly (9% vs 5%; P < .001) vaccinees. CONCLUSIONS: CCIV was well tolerated and highly immunogenic in adults 18 years of age or older. Cell culture may offer greater flexibility of supply during periods of high demand for both seasonal and pandemic vaccines.

Pseudoparticle neutralization is a reliable assay to measure immunity and cross-reactivity to H5N1 influenza viruses.

The standard serological methods present limitations for the measurement of immunity against H5N1 influenza strains. The hemagglutination inhibition (HI) assay lacks sensitivity and requires standardization, while the viral micro-neutralization (MN) assay needs handling 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.

Adjuvanted H5N1 vaccine induces early CD4+ T cell response that predicts long-term persistence of protective antibody levels.

Immune responses to vaccination are tested in clinical trials. This process usually requires years especially when immune memory and persistence are analyzed. Markers able to quickly predict the immune response would be very useful, particularly when dealing with emerging diseases that require a rapid response, such as avian influenza. To address this question we vaccinated healthy adults at days 1, 22, and 202 with plain or MF59-adjuvanted H5N1 subunit vaccines and tested both cell-mediated and antibody responses up to day 382. Only the MF59-H5N1 vaccine induced high titers of neutralizing antibodies, a large pool of memory H5N1-specific B lymphocytes, and H5-CD4(+) T cells broadly reactive with drifted H5. The CD4(+) response was dominated by IL-2(+) IFN-gamma(-) IL-13(-) T cells. Remarkably, a 3-fold increase in the frequency of virus-specific total CD4(+) T cells, measurable after 1 dose, accurately predicted the rise of neutralizing antibodies after booster immunization and their maintenance 6 months later. We suggest that CD4(+) T cell priming might be used as an early predictor of the immunogenicity of prepandemic vaccines.

Combination adjuvants for the induction of potent, long-lasting antibody and T-cell responses to influenza vaccine in mice.

Influenza is controlled by protective titres of neutralizing antibodies, induced with the help of CD4 T-cells, and by antiviral T-cell effector function. Adjuvants are essential for the efficient vaccination of a naïve population against avian influenza. We evaluated a range of adjuvants for their ability to enhance, in naïve mice, protective hemagglutination inhibition (HI) titres, which represent the generally accepted correlate of protection, virus-neutralizing titres and T-cell responses to a new generation influenza vaccine produced in cell culture. The selected adjuvants include alum, calcium phosphate (CAP), MF59, the delivery system poly-(lactide co-glycolide) (PLG) and the immune potentiator CpG. MF59 was clearly the most potent single adjuvant and induced significantly enhanced, long-lasting HI and neutralizing titres and T-cell responses in comparison to all alternatives. The combination of alum, MF59, CAP or PLG with CpG generally induced slightly more potent titres. The addition of CpG to MF59 also induced a more potent Th1 cellular immune response, represented by higher IgG2a titres and the induction of a strongly enhanced IFN-gamma response in splenocytes from immunized mice. These observations have significant implications for the development of new and improved flu vaccines against pandemic and inter-pandemic influenza virus strains.

Safety and immunogenicity of a new fully liquid DTPw-HepB-Hib combination vaccine in infants.

We assessed the safety and immunogenicity of a fully liquid, DTPw-HepB-Hib combination vaccine (Quinvaxem) in comparison with separately administered DTPw-Hib and hepatitis B vaccines. Infants participating in this open-label, randomized, phase II study received a primary vaccination course using a 2-3-4 month schedule. Blood samples were taken immediately prior to the first and one month after the third vaccination. Adverse events were assessed over a 7-day post-vaccination period using subject diaries. After completion of the primary vaccination course, 94.7% [95% CI: 89.8-97.7%] of infants receiving the combination vaccine achieved protective anti-HBs antibody titers (> or = 10 mIU/mL) with a mean 39-fold increase in GMTs in comparison with 99.3% [95% CI: 96.3-100%] seroprotection and a mean 29-fold GMT increase in the comparator group. Diphtheria, tetanus and Haemophilus influenzae type b (Hib) seroprotection rates and pertussis seroconversion rates were also similar between the two groups. There was no statistically significant difference in GMTs for diphtheria between the two groups, but significant differences were shown for tetanus, Hib, and pertussis with higher GMTs for each antigen observed in the comparator group. The combination vaccine was well tolerated, with fever (body temperature > or = 38 degrees C) being the most frequently reported adverse event in both the DTPw-HepB-Hib (12.5% [95% CI: 7.7-18.8%]) and comparator (12.6% [95% CI: 7.7-19.0%]) groups. This study demonstrated that the fully liquid DTPw-HepB-Hib combination vaccine has safety and immunogenicity profiles similar to the DTPw-Hib and hepatitis B vaccines when administered separately.

An MF59-adjuvanted inactivated influenza vaccine containing A/Panama/1999 (H3N2) induced broader serological protection against heterovariant influenza virus strain A/Fujian/2002 than a subunit and a split influenza vaccine.

To test whether inactivated influenza vaccines distributed during the 2003-2004 influenza season in the northern hemisphere were able to confer protection against the mismatched variant A/Fujian/411/2002 virus strain, we measured haemagglutination inhibiting (HI) antibodies in elderly subjects vaccinated with three inactivated vaccines against the homologous A/H3N2 vaccine strain (A/Panama) and against the mismatched A/Fujian strain. The results showed that, while 76 to 80% of elder people vaccinated with conventional vaccines had protected levels of antibodies against the A/Fujian heterovariant strain, those vaccinated with the MF59-adjuvanted vaccine have protective levels of antibodies in >98% of the cases. We conclude that MF59-adjuvanted vaccines confer protection also against influenza virus strains which are not fully matched with those included in the vaccine.