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BACKGROUND Respiratory syncytial virus (RSV) is an important cause of acute respiratory infection, lower respiratory tract disease, clinical complications, and death in older adults. There is currently no licensed vaccine against RSV infection. METHODS In an ongoing, international, placebo-controlled, phase 3 trial, we randomly assigned, in a 1:1 ratio, adults 60 years of age or older to receive a single dose of an AS01E-adjuvanted RSV prefusion F protein-based candidate vaccine (RSVPreF3 OA) or placebo before the RSV season. The primary objective was to show vaccine efficacy of one dose of the RSVPreF3 OA vaccine against RSV-related lower respiratory tract disease, confirmed by reverse-transcriptase polymerase chain reaction (RT-PCR), during one RSV season. The criterion for meeting the primary objective was a lower limit of the confidence interval around the efficacy estimate of more than 20°6. Efficacy against severe RSV-related lower respiratory tract disease and RSV-related acute respiratory infection was assessed, and analyses according to RSV subtype (A and B) were performed. Safety was evaluated. RESULTS A total of 24,966 participants received one dose of the RSVPreF3 OA vaccine (12,467 participants) or placebo (12,499). Over a median follow-up of 6.7 months, vaccine efficacy against RT-PER-confirmed RSV-related lower respiratory tract disease was 82.6% (96.95% confidence interval [CI], 5Z9 to 94.1), with 7 cases (1.0 per 1000 participant-years) in the vaccine group and 40 cases (5.8 per 1000 participant-years) in the placebo group. Vaccine efficacy was 94.1% (95% CI, 62.4 to 99.9) against severe R.SV-related lower respiratory tract disease (assessed on the basis of clinical signs or by the investigator) and 71.7% (95% CI, 56.2 to 82.3) against RSV-related acute respiratory infection. Vaccine efficacy was similar against the RSV A and B subtypes (for RSV-related lower respiratory tract disease: 84.6% and 80.9°6, respectively; for RSV-related acute respiratory infection: 71.9% and 70.6%, respectively). High vaccine efficacy was observed in various age groups and in participants with coexisting conditions. The RSVPreF3 OA vaccine was more reactogenic than placebo, but most adverse events for which reports were solicited were transient, with mild-to-moderate severity. The incidences of serious adverse events and potential immune-mediated diseases were similar in the two groups. CONCLUSIONS A single dose of the RSVPreF3 OA vaccine had an acceptable safety profile and prevented KSV-related acute respiratory infection and lower respiratory tract disease and severe RSV-related lower respiratory tract disease in adults 60 years of age or older, regardless of RSV subtype and the presence of underlying coexisting conditions. (Funded by GlaxoSmithKline Biologicals; AReSVi-006 ClinicalTrials.gov number, NCT04886596.). [ABSTRACT FROM AUTHOR]

Background: The adjuvanted RSV prefusion F protein-based vaccine (RSVPreF3 OA) was efficacious against RSV-related lower respiratory tract disease (RSV-LRTD) in ≥60-years-olds over 1 RSV season. We evaluated efficacy and safety of 1 RSVPreF3 OA dose and of 2 RSVPreF3 OA doses given 1 year apart against RSV-LRTD over 2 RSV seasons post-dose 1., Methods: In this phase 3, blinded trial, ≥60-year-olds were randomized (1:1) to receive RSVPreF3 OA or placebo pre-season 1. RSVPreF3 OA recipients were re-randomized (1:1) to receive a second RSVPreF3 OA dose (RSV_revaccination group) or placebo (RSV_1dose group) pre-season 2; participants who received placebo pre-season 1 received placebo pre-season 2 (placebo group). Efficacy of both vaccine regimens against RSV-LRTD was evaluated over 2 seasons combined (confirmatory secondary objective, success criterion: lower limits of 2-sided CIs around efficacy estimates >20%)., Results: The efficacy analysis comprised 24 967 participants (RSV_1dose: 6227; RSV_revaccination: 6242; placebo: 12 498). Median efficacy follow-up was 17.8 months. Efficacy over 2 seasons of 1 RSVPreF3 OA dose was 67.2% (97.5% CI: 48.2-80.0%) against RSV-LRTD and 78.8% (95% CI: 52.6-92.0%) against severe RSV-LRTD. Efficacy over 2 seasons of a first dose followed by revaccination was 67.1% (97.5% CI: 48.1-80.0%) against RSV-LRTD and 78.8% (95% CI: 52.5-92.0%) against severe RSV-LRTD. Reactogenicity/safety of the revaccination dose were similar to dose 1., Conclusions: One RSVPreF3 OA dose was efficacious against RSV-LRTD over 2 RSV seasons in ≥60-year-olds. Revaccination 1 year post-dose 1 was well tolerated but did not seem to provide additional efficacy benefit in the overall study population., Clinical Trials Registration: ClinicalTrials.gov: NCT04886596., Competing Interests: Potential conflicts of interest . M. G. I. declares that research support from GSK was paid to his previous institution, Northwestern University; he received consulting fees from Adagio Therapeutics, ADMA Biologics, Adamis Pharmaceuticals, AlloVir, Atea, Cidara Therapeutics, Genentech/Roche, Janssen, Shionogi, Takeda, Talaris, and Eurofins Viracor; and payment for participating in data safety monitoring boards or advisory boards from Adamis Pharmaceuticals, AlloVir, National Institutes of Health, CSL Behring, Janssen, Merck, Seqirus, Takeda, and Talaris; all of these ended in December 2022; M. G. I. also receives author royalties from UpToDate, which is ongoing, and serves as Chair of the International Society for Influenza and other Respiratory Virus Diseases Antiviral Group and was Editor-in-Chief of Transplant Infectious Disease. A. P. declares funding from GSK for conducting the trial. A. P. also declares that his institution received grants from Chiesi, AstraZeneca, GSK, Sanofi, and Agenzia Italiana del Farmaco; that he received consulting fees from Chiesi, AstraZeneca, GSK, Novartis, Sanofi, Avillion, and ELPEN Pharmaceuticals; payment for participation in advisory boards from Chiesi, AstraZeneca, GSK, Novartis, Sanofi, IQVIA, Avillion, and ELPEN Pharmaceuticals; and honoraria from Chiesi, AstraZeneca, GSK, Menarini, Novartis, Zambon, Mundipharma, Sanofi, Edmond Pharmaceuticals, IQVIA, Avillion, and ELPEN Pharmaceuticals. R. G. F. declares having received payment from GSK for lectures and support for travel related to these activities. J. M. L. reports grants from GSK paid to her institution for the conduct of the trial and from GSK, Pfizer, Merck, Moderna, Sanofi, Inventprise, and VBI Vaccines for other trials; J. M. L. also reports being a board member of Seqirus and participating on a data safety monitoring board or advisory board for Vaxcyte; she is an expert panelist for Canada's Drug and Health Technology Agency for the review of nirsevimab. I. L.-R. declares that her institution received funding from GSK for conducting this trial; from Icosavax, Virometix, Janssen Vaccines, Curevac, Moderna, Osivax, MSD, ICON Genetics, and OSE Immunotherapeutics for other vaccine trials; from Janssen Vaccines and MSD for consulting services; and from Janssen Vaccines for participation on a data safety monitoring board or advisory board. F. M.-T. declares that his institution received payment from GSK for conducting this trial and from Ablynx, Abbott, Seqirus, Sanofi, MSD, Merck, Pfizer, Roche, Regeneron, Janssen, Medimmune, Novavax, Novartis, and GSK for other vaccine trials; F. M.-T. also reports receiving honoraria for lectures from Sanofi, MSD, Moderna, GSK, Biofabri, AstraZeneca, Novavax, Janssen, and Pfizer; payment of travel expenses and meeting fees from Pfizer, MSD, GSK, and Sanofi; and participation on data safety monitoring boards or advisory boards for Pfizer and Biofabri; F. M.-T. is also a member of the World Health Organization’s (WHO's) European Technical Advisory Group of Experts, coordinator of the Spanish Pediatric Clinical Trials Network, and coordinator of the WHO Collaborating Center for Vaccine Safety of Santiago de Compostela. T. F. S. reports honoraria and/or participation on data safety monitoring boards or advisory boards from Alexion, AstraZeneca, Bavarian Nordic, Biogen, Biontech, GSK, Janssen-Cilag, Merck-Serono, Moderna, MSD, Novavax, Pfizer, Roche, Sanofi-Aventis, Seqirus, Synlab, Takeda, and va-Q-tec. R. N. v. Z.-S. reports that his institution received support from Boehringer Ingelheim for the Interstitial Lung Diseases (ILD) registry and that he received consulting fees from GSK and honoraria for lectures from Glenmark, Boehringer Ingelheim, Cipla, and Novartis; R. N. v. Z.-S. also participated on data safety monitoring boards or advisory boards for OnQ SA; he is president of the South African Thoracic Society and co-chair of the International Health Committee of the American Thoracic Society. C. V., N. D., O. G., L. F., M.-P. D., L. K., V. H., A. O., M. V. d. W., and D. D. are employed by GSK and have stock options or shares from GSK. N. D. is co-applicant on a pending patent for vaccination against RSV and has stock options from Haleon. L. F., M.-P. D., A. O., and M. V. d. W. are co-applicants on a pending patent filed by GSK. The other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: Older adults with chronic cardiorespiratory or endocrine/metabolic conditions are at increased risk of respiratory syncytial virus (RSV)-related acute respiratory illness (RSV-ARI) and severe respiratory disease. In an ongoing, randomized, placebo-controlled, multicountry, phase 3 trial in ≥60-year-old participants, an AS01E-adjuvanted RSV prefusion F protein-based vaccine (RSVPreF3 OA) was efficacious against RSV-related lower respiratory tract disease (RSV-LRTD), severe RSV-LRTD, and RSV-ARI. We evaluated efficacy and immunogenicity among participants with coexisting cardiorespiratory or endocrine/metabolic conditions that increase the risk of severe RSV disease ("conditions of interest")., Methods: Medically stable ≥60-year-old participants received 1 dose of RSVPreF3 OA or placebo. Efficacy against first RSV-LRTD and RSV-ARI episodes was assessed in subgroups with/without coexisting cardiorespiratory or endocrine/metabolic conditions of interest. Immunogenicity was analyzed post hoc in these subgroups., Results: In total, 12 467 participants received RSVPreF3 OA and 12 499 received placebo. Of these, 39.6% (RSVPreF3 OA) and 38.9% (placebo) had ≥1 coexisting condition of interest. The median efficacy follow-up was 6.7 months. Efficacy against RSV-LRTD was high in participants with ≥1 condition of interest (94.6%), ≥1 cardiorespiratory (92.1%), ≥1 endocrine/metabolic (100%), and ≥2 conditions of interest (92.0%). Efficacy against RSV-ARI was 81.0% in participants with ≥1 condition of interest (88.1% for cardiorespiratory, 79.4% for endocrine/metabolic conditions) and 88.0% in participants with ≥2 conditions of interest. Postvaccination neutralizing titers were at least as high in participants with ≥1 condition of interest as in those without., Conclusions: RSVPreF3 OA was efficacious against RSV-LRTD and RSV-ARI in older adults with coexisting medical conditions associated with an increased risk of severe RSV disease., Clinical Trials Registration: ClinicalTrials.gov: NCT04886596., Competing Interests: Potential conflicts of interest. R. G. F. declares having received payment from GSK as a speaker for promotional programs and support for travel related to these activities. R. A. I. declares that his institution received a grant from GSK for conducting the trial. K. S. declares that her institution received funding from GSK for conducting the trial and that she is a member of the independent data monitoring committee for the AReSVi-006 trial (without receiving payment). D. G. L. and A. P. declare funding from GSK for conducting the trial. A. P. declares that his institution received grants from Chiesi, AstraZeneca, GSK, Sanofi, and Agenzia Italiana del Farmaco; that he received consulting fees from Chiesi, AstraZeneca, GSK, Novartis, Sanofi, Avillion, and ELPEN Pharmaceuticals; payment for participation in data safety monitoring boards or advisory boards from Chiesi, AstraZeneca, GSK, MSD, Novartis, Sanofi, IQVIA, Avillion, and ELPEN Pharmaceuticals; and honoraria from Chiesi, AstraZeneca, GSK, Menarini, Novartis, Zambon, Mundipharma, Sanofi, Edmond Pharmaceuticals, IQVIA, Avillion, and ELPEN Pharmaceuticals. M. G. I. declares that his institution received funding from GSK for RSV vaccine trials; he also received author royalties from UpToDate, consulting fees from Adagio Therapeutics, ADMA Biologics, AlloVir, Atea, Cidara Therapeutics, Genentech/Roche, Janssen, Shionogi, Takeda, and Eurofins Viracor, and payment for participating in data safety monitoring boards or advisory boards from Adamis Pharmaceuticals, AlloVir, CSL Behring, Janssen, Merck, Seqirus, Takeda, and Talaris. L. F., M. P. D., C. M., M. V. d. W., L. K., and V. H. are employed by GSK; L. F., M. P. D., C. M., M. V. d. W., V. H., and L. K. have stock options or shares from GSK. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: The aim of this study was to investigate safety and immunogenicity of vaccine formulations against respiratory syncytial virus (RSV) containing the stabilized prefusion conformation of RSV fusion protein (RSVPreF3)., Methods: This phase 1/2, randomized controlled, observer-blind study enrolled 48 young adults (YAs; aged 18-40 years) and 1005 older adults (OAs; aged 60-80 years) between January and August 2019. Participants were randomized into equally sized groups to receive 2 doses of unadjuvanted (YAs and OAs) or AS01-adjuvanted (OAs) vaccine or placebo 2 months apart. Vaccine safety and immunogenicity were assessed until 1 month (YAs) or 12 months (OAs) after second vaccination., Results: The RSVPreF3 vaccines boosted humoral (RSVPreF3-specific immunoglobulin G [IgG] and RSV-A neutralizing antibody) responses, which increased in an antigen concentration-dependent manner and were highest after dose 1. Compared to prevaccination, the geometric mean frequencies of polyfunctional CD4+ T cells increased after each dose and were significantly higher in adjuvanted than unadjuvanted vaccinees. Postvaccination immune responses persisted until end of follow-up. Solicited adverse events were mostly mild to moderate and transient. Despite a higher observed reactogenicity of AS01-containing vaccines, no safety concerns were identified for any assessed formulation., Conclusions: Based on safety and immunogenicity profiles, the AS01E-adjuvanted vaccine containing 120 μg of RSVPreF3 was selected for further clinical development., Clinical Trials Registration: NCT03814590., Competing Interests: Potential conflicts of interest. D. C., M.-P. D., M. d. H., N. D. S., N. D., L. F., V. H., J. K., N. M., B. S., F. S., J. T., C. V. A., and C. Ve. are/were employees of the GSK group of companies at the time of the study conduct. C. Va. is currently an employee of the GSK group of companies. D. C., M.-P. D., M. d. H., N. D. S., N. D., B. S., F. S., and C. Ve. hold shares from the GSK group of companies as part of their past/current employee remuneration. F. S. is currently an employee of Janssen Pharmaceutical Companies of Johnson & Johnson and holds restricted shares from Johnson & Johnson as part of his employee remuneration. All current/previous employees of the GSK groups of companies declare financial and nonfinancial relationships and activities. C. P. A., E. K., I. L.-R., K. S., and C. Va. report grant/research support from the GSK group of companies to their institution for study conduct and, except for C. Va., they have no nonfinancial relationships and activities to declare. E. K. has served as consultant, in advisory boards, in speaker’s bureaus, or received travel reimbursement from Amphastar, AstraZeneca, Boehringer Ingelheim, Forest, Cipla, Chiesi, GSK, Mylan, Novartis, Sunovion, Teva, Pearl Pharmaceuticals, and Theravance. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

A recombinant respiratory syncytial virus (RSV) fusion glycoprotein candidate vaccine (RSV-PreF) manufactured in Chinese hamster ovary cells was developed for immunization of pregnant women, to protect newborns against RSV disease through trans-placental antibody transfer. Traces of a host-cell protein, hamster neogenin (haNEO1), were identified in purified RSV-PreF antigen material. Given the high amino-acid sequence homology between haNEO1 and human neogenin (huNEO1), there was a risk that potential vaccine-induced anti-neogenin immunity could affect huNEO1 function in mother or fetus. Anti-huNEO1 IgGs were measured by enzyme-linked immunosorbent assay in sera from rabbits and trial participants (Phase 1 and 2 trials enrolling 128 men and 500 non-pregnant women, respectively; NCT01905215/NCT02360475) collected after immunization with RSV-PreF formulations containing different antigen doses with/without aluminum-hydroxide adjuvant. In rabbits, four injections administered at 14-day intervals induced huNEO1-specific IgG responses in an antigen-dose- and adjuvant-dependent manner, which plateaued in the highest-dose groups after three injections. In humans, no vaccination-induced anti-huNEO1 IgG responses were detected upon a single immunization, as the values in vaccine and control groups fluctuated around pre-vaccination levels up to 90/360 days post-vaccination. A minority of participants had anti-huNEO1 levels ≥ assay cutoff before vaccination, which did not increase post-vaccination. Thus, despite detecting vaccine-induced huNEO1-specific responses in rabbits, we found no evidence that the candidate vaccine had induced anti-huNEO1 immunity in human adults. The antigen purification process was nevertheless optimized, and haNEO1-reduced vaccines were used in a subsequent Phase 2 trial enrolling 400 non-pregnant women (NCT02956837), in which again no vaccine-induced anti-huNEO1 responses were detected.

Background: Adjuvants like AS01 B increase the immunogenicity of vaccines and generally cause increased transient reactogenicity compared with Alum. A phase II randomized trial was conducted to characterize the response to AS01 B and Alum adjuvanted vaccines. A post-hoc analysis was performed to examine the associations between reactogenicity and innate immune parameters., Methods: The trial involved 60 hepatitis B-naïve adults aged 18-45 years randomized 1:1 to receive either two doses of HBsAg-AS01 B on Day (D)0 and D30, or three doses of HBsAg-Alum on D0, D30, D180. Prior to vaccination, all subjects received placebo injection in order to differentiate the impact of injection process and the vaccination. Main outcomes included reactogenicity symptoms, vital signs, blood cytokines, biochemical and hematological parameters after vaccination. Associations were explored using linear regression., Findings: The vaccine with AS01 B induced higher HBsAg-specific antibody levels than Alum. Local and systemic symptoms were more frequent in individuals who received HBsAg AS01 B /Alum vaccine or placebo, but were mild and short-lived. Blood levels of C-reactive protein (CRP), bilirubin, leukocyte, monocyte and neutrophil counts increased rapidly and transiently after AS01 B but not after Alum or placebo. Lymphocyte counts decreased in the AS01 B group and lactate dehydrogenase levels decreased after Alum. Modelling revealed associations between systemic symptoms and increased levels of CRP and IL-6 after the first HBsAg-AS01 B or HBsAg-Alum immunization. Following the second vaccine dose, CRP, IL-6, IP-10, IFN-γ, MIP-1β and MCP-2 were identified as key parameters associated with systemic symptoms. These observations were confirmed using an independent data set extracted from a previous study of the immune response to HBsAg-adjuvanted vaccines (NCT00805389)., Conclusions: IL-6 and IFN-γ signals were associated with systemic reactogenicity following administration of AS01 B -adjuvanted vaccine. These signals were similar to those previously associated with antibody and T-cell responses induced by HBsAg-adjuvanted vaccines, suggesting that similar innate immune signals may underlie adjuvant reactogenicity and immunogenicity., Trial Registration: www.clinicaltrials.gov NCT01777295., (Copyright © 2019 GlaxoSmithKline Biologicals SA. Published by Elsevier Ltd.. All rights reserved.)

To elucidate the role of innate responses in vaccine immunogenicity, we compared early responses to hepatitis B virus (HBV) surface antigen (HBsAg) combined with different Adjuvant Systems (AS) in healthy HBV-naïve adults, and included these parameters in multi-parametric models of adaptive responses. A total of 291 participants aged 18-45 years were randomized 1:1:1:1:1 to receive HBsAg with AS01 B , AS01 E , AS03, AS04, or Alum/Al(OH) 3 at days 0 and 30 (ClinicalTrials.gov: NCT00805389). Blood protein, cellular, and mRNA innate responses were assessed at early time-points and up to 7 days after vaccination, and used with reactogenicity symptoms in linear regression analyses evaluating their correlation with HBs-specific CD4 + T-cell and antibody responses at day 44. All AS induced transient innate responses, including interleukin (IL)-6 and C-reactive protein (CRP), mostly peaking at 24 h post-vaccination and subsiding to baseline within 1-3 days. After the second but not the first injection, median interferon (IFN)-γ levels were increased in the AS01 B group, and IFN-γ-inducible protein-10 levels and IFN-inducible genes upregulated in the AS01 and AS03 groups. No distinct marker or signature was specific to one particular AS. Innate profiles were comparable between AS01 B , AS01 E , and AS03 groups, and between AS04 and Alum groups. AS group rankings within adaptive and innate response levels and reactogenicity prevalence were similar (AS01 B  ≥ AS01 E  > AS03 > AS04 > Alum), suggesting an association between magnitudes of inflammatory and vaccine responses. Modeling revealed associations between adaptive responses and specific traits of the innate response post-dose 2 (activation of the IFN-signaling pathway, CRP and IL-6 responses). In conclusion, the ability of AS01 and AS03 to enhance adaptive responses to co-administered HBsAg is likely linked to their capacity to activate innate immunity, particularly the IFN-signaling pathway.

Background:  Respiratory syncytial virus (RSV) is a leading cause of childhood bronchiolitis and pneumonia, particularly in early infancy. Immunization of pregnant women could boost preexisting immune responses, providing passive protection to newborns through placental transfer of anti-RSV antibody., Methods:  In this first-in-humans clinical trial of a purified recombinant RSV protein F vaccine engineered to preferentially maintain prefusion conformation (RSV-PreF), 128 healthy men 18-44 years old were randomized to one dose of a RSV-PreF vaccine containing 10, 30, or 60 µg of RSV-PreF antigen, with or without alum adjuvant, or control, and followed for one year for safety and immunogenicity outcomes., Results:  Injection site pain was the most common adverse event, reported by up to 81.3% of participants. The highest RSV neutralizing antibody responses were in the 30 µg RSV-PreF/alum, 60 µg RSV-PreF/alum, and 60 µg RSV-PreF/nonadjuvant groups. Responses were evident on day 7, and 30 days after vaccination these participants had RSV-A neutralizing antibody titers of ≥1:512, and >70% had titers of 1:1024, with titers increasing by 3.2-4.9 fold. Responses remained high on day 60 but waned on days 180 and 360., Conclusions:  The RSV-PreF vaccine elicited rapid RSV neutralizing antibody responses in healthy young men, with an acceptable adverse event profile., (© The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.)

Immunogenicity and safety of different adjuvants combined with a model antigen (HBsAg) were compared. Healthy HBV-naïve adults were randomized to receive HBs adjuvanted with alum or Adjuvant Systems AS01B, AS01E, AS03A or AS04 at Days 0 and 30. Different frequencies of HBs-specific CD4+ T cells 14days post dose 2 but similar polyfunctionality profiles were induced by the different adjuvants with frequencies significantly higher in the AS01B and AS01E groups than in the other groups. Antibody concentrations 30days post-dose 2 were significantly higher in AS01B, AS01E and AS03A than in other groups. Limited correlations were observed between HBs-specific CD4+ T cell and antibody responses. Injection site pain was the most common solicited local symptom and was more frequent in AS groups than in alum group. Different adjuvants formulated with the same antigen induced different adaptive immune responses and reactogenicity patterns in healthy naïve adults. The results summary for this study (GSK study number 112115 - NCT# NCT00805389) is available on the GSK Clinical Study Register and can be accessed at www.gsk-clinicalstudyregister.com., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

This phase II study evaluated the effect of chloroquine on the specific CD8(+) T-cell responses to and the safety of a booster dose of investigational human immunodeficiency virus type 1 (HIV-1) F4/AS01(B) vaccine containing 10 μg of recombinant fusion protein (F4) adjuvanted with the AS01(B) adjuvant system. Healthy adults aged 21 to 41 years, primed 3 years before with two F4/AS01(B) doses containing 10 or 30 μg of F4 (ClinicalTrials.gov registration number NCT00434512), were randomized (1:1) to receive the F4/AS01(B) booster administered alone or 2 days after chloroquine (300 mg). F4-specific CD8(+)/CD4(+) T-cell responses were characterized by intracellular cytokine staining and lymphoproliferation assays and anti-F4 antibodies by enzyme-linked immunosorbent assays (ELISAs). No effect of chloroquine on CD4(+)/CD8(+) T-cell and antibody responses and no vaccine effect on CD8(+) T-cell responses (cytokine secretion or proliferation) were detected following F4/AS01(B) booster administration. In vitro, chloroquine had a direct inhibitory effect on AS01(B) adjuvant properties; AS01-induced cytokine production decreased upon coincubation of cells with chloroquine. In the pooled group of participants primed with F4/AS01(B) containing 10 μg of F4, CD4(+) T-cell and antibody responses induced by primary vaccination persisted for at least 3 years. The F4/AS01(B) booster induced strong F4-specific CD4(+) T-cell responses, which persisted for at least 6 months with similar frequencies and polyfunctional phenotypes as following primary vaccination, and high anti-F4 antibody concentrations, reaching higher levels than those following primary vaccination. The F4/AS01(B) booster had a clinically acceptable safety and reactogenicity profile. An F4/AS01(B) booster dose, administered alone or after chloroquine, induced robust antibody and F4-specific CD4(+) T-cell responses but no significant CD8(+) T-cell responses (cytokine secretion or proliferation) in healthy adults. (This study has been registered at ClinicalTrials.gov under registration number NCT00972725).

Long-term immunity, evaluated by the persistence of antibody titers, is important to assess duration of protection induced by vaccination. This paper aims at drawing awareness on the risk of misinterpreting persistence results in absence of adjustment for missing or left-censored data. Using simulations, the paper shows that repeated measurement models are an appropriate alternative to control the bias associated to unadjusted persistence results.

Background: This open, randomized clinical trial (NCT00758264) evaluated the coadministration of a booster dose of the 10-valent pneumococcal conjugate vaccine (PHiD-CV) and a single dose of the tetravalent meningococcal conjugate vaccine (MenACWY-TT) in Taiwanese and Mexican toddlers., Methods: Healthy toddlers aged 12-23 months (N = 363) were randomized (2:1:1) to receive either both vaccines at first visit, MenACWY-TT at first visit and 1 month later PHiD-CV, or PHiD-CV at first visit and 1 month later MenACWY-TT. Immune responses were measured 1 month after MenACWY-TT vaccination by meningococcal serum bactericidal activity (rSBA) assay and 1 month after PHiD-CV vaccination by pneumococcal 22F-inhibition enzyme-linked immunosorbent assay and functional opsonophagocytic activity assay. Solicited and unsolicited symptoms were recorded for days 4 and 31 postvaccination, respectively. Serious adverse events were recorded throughout the study., Results: The prespecified criteria for noninferiority of coadministration versus individual administrations were met for all meningococcal serogroups (in terms of percentages of toddlers with rSBA titer ≥8) and all vaccine pneumococcal serotypes (in terms of antibody geometric mean concentration ratios), except pneumococcal serotype 18C. For each meningococcal serogroup, ≥97.5% of toddlers across the 3 groups had rSBA titers ≥128 at 1 month after MenACWY-TT vaccination. For each pneumococcal serotype, at 1 month after PHiD-CV vaccination, ≥96.0% and ≥92.9% of toddlers across the 3 groups had antibody concentrations ≥0.2 µg/mL and opsonophagocytic activity titers ≥8, respectively. The safety profiles of both vaccines when coadministered were clinically acceptable., Conclusions: This study supports the coadministration of PHiD-CV and MenACWY-TT in toddlers.