Safety and immunogenicity after a 30-month boost of a subtype C ALVAC-HIV (vCP2438) vaccine prime plus bivalent subtype C gp120/MF59 vaccine boost (HVTN 100): A phase 1-2 randomized double-blind placebo-controlled trial.

Induction of broad, durable immune responses is a challenge in HIV vaccine development. HVTN 100 Part A administered subtype C-containing ALVAC-HIV at months 0 and 1, and ALVAC-HIV with bivalent subtype C gp120/MF59 at months 3, 6 and 12. As IgG binding antibody and T-cell responses were similar or greater at month 12.

Safety and immunogenicity of a subtype C ALVAC-HIV (vCP2438) vaccine prime plus bivalent subtype C gp120 vaccine boost adjuvanted with MF59 or alum in healthy adults without HIV (HVTN 107): A phase 1/2a randomized trial.

Background: Adjuvants are widely used to enhance and/or direct vaccine-induced immune responses yet rarely evaluated head-to-head. Our trial directly compared immune responses elicited by MF59 versus alum adjuvants in the RV144-like HIV vaccine regimen modified for the Southern African region. The RV144 trial of a recombinant canarypox vaccine vector expressing HIV env subtype B (ALVAC-HIV) prime followed by ALVAC-HIV plus a bivalent gp120 protein vaccine boost adjuvanted with alum is the only trial to have shown modest HIV vaccine efficacy.

Efficacy of a monovalent (D614) SARS-CoV-2 recombinant protein vaccine with AS03 adjuvant in adults: a phase 3, multi-country study.

Background: The literature on first generation COVID-19 vaccines show they were less effective against new SARS-CoV-2 variants of concern including Omicron (BA.1, BA.2, BA.

Protein Dose-Sparing Effect of AS01B Adjuvant in a Randomized Preventive HIV Vaccine Trial of ALVAC-HIV (vCP2438) and Adjuvanted Bivalent Subtype C gp120.

Background: HVTN 120 is a phase 1/2a randomized double-blind placebo-controlled human immunodeficiency virus (HIV) vaccine trial that evaluated the safety and immunogenicity of ALVAC-HIV (vCP2438) and MF59- or AS01B-adjuvanted bivalent subtype C gp120 Env protein at 2 dose levels in healthy HIV-uninfected adults.

Methods: Participants received ALVAC-HIV (vCP2438) alone or placebo at months 0 and 1. At months 3 and 6, participants received either placebo, ALVAC-HIV (vCP2438) with 200 μg of bivalent subtype C gp120 adjuvanted with MF59 or AS01B, or ALVAC-HIV (vCP2438) with 40 μg of bivalent subtype C gp120 adjuvanted with AS01B.

Efficacy of a bivalent (D614 + B.1.351) SARS-CoV-2 recombinant protein vaccine with AS03 adjuvant in adults: a phase 3, parallel, randomised, modified double-blind, placebo-controlled trial.

Background: COVID-19 vaccines with alternative strain compositions are needed to provide broad protection against newly emergent SARS-CoV-2 variants of concern. This study aimed to describe the clinical efficacy and safety of a bivalent SARS-CoV-2 recombinant protein vaccine as a two-injection primary series during a period of circulation of the omicron (B.1.

Efficacy of a bivalent (D614 + B.1.351) SARS-CoV-2 Protein Vaccine.

Background: COVID-19 vaccines with alternative strain compositions are needed to provide broad protection against newly emergent SARS-CoV-2 variants of concern.

Methods: We conducted a global Phase 3, multi-stage efficacy study (NCT04904549) among adults aged ≥18 years. Participants were randomized 1:1 to receive two intramuscular injections 21 days apart of a bivalent SARS-CoV-2 recombinant protein vaccine with AS03-adjuvant (5 μg of ancestral (D614) and 5 μg of B.

Analysis of the HIV Vaccine Trials Network 702 Phase 2b-3 HIV-1 Vaccine Trial in South Africa Assessing RV144 Antibody and T-Cell Correlates of HIV-1 Acquisition Risk.

Background: The ALVAC/gp120 + MF59 vaccines in the HIV Vaccine Trials Network (HVTN) 702 efficacy trial did not prevent human immunodeficiency virus-1 (HIV-1) acquisition. Vaccine-matched immunological endpoints that were correlates of HIV-1 acquisition risk in RV144 were measured in HVTN 702 and evaluated as correlates of HIV-1 acquisition.

Methods: Among 1893 HVTN 702 female vaccinees, 60 HIV-1-seropositive cases and 60 matched seronegative noncases were sampled.

Accuracy and efficacy of pre-dengue vaccination screening for previous dengue infection with a new dengue rapid diagnostic test: a retrospective analysis of phase 3 efficacy trials.

Background: A dengue pre-vaccination test that is convenient, highly specific, and highly sensitive is still needed. The OnSite Dengue IgG rapid diagnostic test (RDT) is a new rapid diagnostic test specifically designed for pre-vaccination screening. We aimed to retrospectively assess the efficacy of a tetravalent dengue vaccine (CYD-TDV) in participants determined to be dengue seropositive by the OnSite IgG RDT and to evaluate assay performances.

Safety and immunogenicity of an AS03-adjuvanted SARS-CoV-2 recombinant protein vaccine (CoV2 preS dTM) in healthy adults: interim findings from a phase 2, randomised, dose-finding, multicentre study.

Background: We evaluated our SARS-CoV-2 prefusion spike recombinant protein vaccine (CoV2 preS dTM) with different adjuvants, unadjuvanted, and in a one-injection and two-injection dosing schedule in a previous phase 1-2 study. Based on interim results from that study, we selected a two-injection schedule and the AS03 adjuvant for further clinical development. However, lower than expected antibody responses, particularly in older adults, and higher than expected reactogenicity after the second vaccination were observed.

Analysis of Neutralizing Antibodies as a Correlate of Instantaneous Risk of Hospitalized Dengue in Placebo Recipients of Dengue Vaccine Efficacy Trials.

Background: In the CYD14 (NCT01373281) and CYD15 (NCT01374516) dengue vaccine efficacy trials, month 13 neutralizing antibody (nAb) titers correlated inversely with risk of symptomatic, virologically confirmed dengue (VCD) between month 13 (1 month after final dose) and month 25. We assessed nAb titer as a correlate of instantaneous risk of hospitalized VCD (HVCD), for which participants were continually surveilled for 72 months.

Methods: Using longitudinal nAb titers from the per-protocol immunogenicity subsets, we estimated hazard ratios (HRs) of HVCD by current nAb titer value for 3 correlate/endpoint pairs: average titer across all 4 serotypes/HVCD of any serotype (HVCD-Any), serotype-specific titer/homologous HVCD, and serotype-specific titer/heterologous HVCD.

Safety and immunogenicity of SARS-CoV-2 recombinant protein vaccine formulations in healthy adults: interim results of a randomised, placebo-controlled, phase 1-2, dose-ranging study.

Background: CoV2 preS dTM is a stabilised pre-fusion spike protein vaccine produced in a baculovirus expression system being developed against SARS-CoV-2. We present interim safety and immunogenicity results of the first-in-human study of the CoV2 preS dTM vaccine with two different adjuvant formulations.

Methods: This phase 1-2, randomised, double-blind study is being done in healthy, SARS-CoV-2-seronegative adults in ten clinical research centres in the USA.

Analysis of Hospitalized and Severe Dengue Cases Over the 6 years of Follow-up of the Tetravalent Dengue Vaccine (CYD-TDV) Efficacy Trials in Asia and Latin America.

Background: CYD-TDV, a live, attenuated, tetravalent dengue vaccine, has been approved for the prevention of symptomatic dengue in previously dengue exposed individuals. This post hoc analysis assessed hospitalized and severe virologically confirmed dengue (VCD) over the complete 6-year follow-up of 3 CYD-TDV efficacy studies (CYD14, CYD15, and CYD23/CYD57).

Methods: The main outcomes were hazard ratios (HRs) for hospitalized or severe VCD by baseline dengue serostatus, focusing on those who were seropositive, and by age at immunization (<9 years/≥9 years).

Immunobridging efficacy of a tetravalent dengue vaccine against dengue and against hospitalized dengue from children/adolescents to adults in highly endemic countries.

Background: The recombinant tetravalent live-attenuated dengue vaccine based on the YF 17D vaccine virus backbone (CYD-TDV) demonstrated vaccine efficacy (VE) against symptomatic, virologically confirmed dengue of any serotype from month 13 to month 25 (VCD-DENV-AnyM13→M25) in the CYD14 (2-14-y-olds) and CYD15 (9-16-y-olds) phase 3 trials. Fifty percent plaque reduction neutralization test (PRNT50) titers are a potential surrogate for immunobridging VE to adults.

Methods: Using PRNT50 calibration datasets, we applied immunobridging approaches using baseline and/or M13 PRNT50 titers to estimate VE against VCD-DENV-AnyM0→M25 and against hospitalized VCD (HVCD)-DENV-AnyM0→M72 in hypothetical 18-45-y-old and 46-50-y-old CYD14 and CYD15 cohorts.

Accuracy and efficacy of pre-dengue vaccination screening for previous dengue infection with five commercially available immunoassays: a retrospective analysis of phase 3 efficacy trials.

Background: The tetravalent dengue vaccine (CYD-TDV) has been shown to provide protection against dengue disease over 5-year follow-up in participants with previous dengue infection, but increased the risk of dengue hospitalisation and severe dengue during long-term follow-up in those without previous dengue infection. WHO recommended pre-vaccination screening to identify those with previous dengue infection (ie, dengue seropositive) who would benefit from vaccination. We re-evaluated CYD-TDV efficacy in those identified as dengue seropositive using five commercially available immunoassays, and assessed immunoassay performance.

Immunogenicity and safety of simplified vaccination schedules for the CYD-TDV dengue vaccine in healthy individuals aged 9-50 years (CYD65): a randomised, controlled, phase 2, non-inferiority study.

Background: Three doses of the licensed tetravalent dengue vaccine CYD-TDV (Dengvaxia, Sanofi Pasteur, Lyon France) are immunogenic and effective against symptomatic dengue in individuals aged 9 years and older who are dengue seropositive. Previous trials have provided some evidence that antibody responses elicited after just one dose or two doses of CYD-TDV might be similar to those elicited after three doses. We compared antibody responses following one-dose, two-dose, and three-dose vaccination regimens in individuals who were dengue seropositive at baseline up to 1 year after the last injection.

Zika and Dengue Interactions in the Context of a Large Dengue Vaccine Clinical Trial in Latin America.

A phase III dengue vaccine trial including 9- to 16-year-olds in Latin America (NCT01374516) was ongoing at the time of a Zika outbreak. We explored interactions between dengue and Zika, in the context of dengue vaccination. Symptomatic virologically confirmed Zika (VCZ) was evaluated using acute-phase sera from febrile participants (January 2013-March 2018).

Immune Response Persistence and Safety of a Booster Dose of the Tetravalent Dengue Vaccine in Adolescents and Adults Who Previously Completed the 3-dose Schedule 4-5 Years Earlier in Latin America: A Randomized Placebo-controlled Trial.

Background: We previously described an increased immune response 28 days after a booster dose of the live, attenuated, tetravalent dengue vaccine (CYD-TDV) in healthy adolescents and adults in Latin America (CYD64, NCT02623725). This follow-up study evaluated immune response persistence and safety of a CYD-TDV booster dose up to Month (M) 24 post-booster.

Methods: This study included 250 participants who previously received 3 primary doses of CYD-TDV in the CYD13 (NCT00993447) and CYD30 (NCT01187433) studies, and who were randomized 4-5 years later to receive a CYD-TDV booster or placebo (3:1).

Efficacy after 1 and 2 doses of CYD-TDV in dengue endemic areas by dengue serostatus.

A simplified dose regimen of the live, attenuated, tetravalent dengue vaccine (CYD-TDV) could have the potential to facilitate easier implementation of immunization programs against symptomatic virologically-confirmed dengue (VCD) in dengue seropositive individuals aged ≥ 9 years. This post-hoc analysis of two Phase III studies (CYD14 [NCT01373281] and CYD15 [NCT01374516]) in dengue endemic areas assessed the efficacy of CYD-TDV by dengue serostatus between dose 1 and 2 (at Month [M] 6), between dose 2 and 3 (at M12), and from dose 3 to M25. Baseline dengue serostatus (seropositive or seronegative) was determined based on measured dengue neutralizing antibody titers with the 50% plaque reduction neutralization test (PRNT) or ascertained by logistic regression-based multiple imputation (MI) to predict PRNT.

Microneutralization assay titer correlates analysis in two phase 3 trials of the CYD-TDV tetravalent dengue vaccine in Asia and Latin America.

We previously showed that Month 13 50% plaque reduction neutralization test (PRNT50) neutralizing antibody (nAb) titers against dengue virus (DENV) correlated with vaccine efficacy (VE) of CYD-TDV against symptomatic, virologically-confirmed dengue (VCD) in the CYD14 and CYD15 Phase 3 trials. While PRNT is the gold standard nAb assay, it is time-consuming and costly. We developed a next-generation high-throughput microneutralization (MN) assay and assessed its suitability for immune-correlates analyses and immuno-bridging applications.

A phase 1b randomized study of the safety and immunological responses to vaccination with H4:IC31, H56:IC31, and BCG revaccination in -uninfected adolescents in Cape Town, South Africa.

Background: Tuberculosis (TB) remains the leading cause of infectious disease-related death. Recently, a trial of BCG revaccination and vaccination with H4:IC31, a recombinant protein vaccine, in South African adolescents (Aeras C-040-404) showed efficacy in preventing sustained QuantiFERON (QFT) conversion, a proxy for () infection. A phase 1b trial of 84 South African adolescents was conducted, concurrent with Aeras C-040-404, to assess the safety and immunogenicity of H4:IC31, H56:IC31 and BCG revaccination, and to identify and optimize immune assays for identification of candidate correlates of protection in efficacy trials.

Assessment of the long-term efficacy of a dengue vaccine against symptomatic, virologically-confirmed dengue disease by baseline dengue serostatus.

CYD-TDV is a live, attenuated, tetravalent dengue vaccine licensed in 21 countries. We undertook a post-hoc analysis of the long-term efficacy of CYD-TDV during the surveillance expansion phase (SEP) of two Phase III studies (CYD14 in the Asia-Pacific region; CYD15 in Latin America). The SEP included approximately Year 5 and the entire Year 6 of follow-up after the first study injection.

CYD Tetravalent Dengue Vaccine Performance by Baseline Immune Profile (Monotypic/Multitypic) in Dengue-Seropositive Individuals.

Background: The immune profile of dengue-experienced individuals is a determinant of dengue reinfection severity risk. Individuals with a single prior dengue infection (monotypic) are at highest risk for severe disease, while individuals with ≥ 2 prior dengue infections (multitypic) are at lower risk. The tetravalent dengue vaccine (CYD-TDV) has shown efficacy in the prevention of dengue in individuals with prior dengue infection.

Safety and immune responses after a 12-month booster in healthy HIV-uninfected adults in HVTN 100 in South Africa: A randomized double-blind placebo-controlled trial of ALVAC-HIV (vCP2438) and bivalent subtype C gp120/MF59 vaccines.

Background: HVTN 100 evaluated the safety and immunogenicity of an HIV subtype C pox-protein vaccine regimen, investigating a 12-month booster to extend vaccine-induced immune responses.

Methods And Findings: A phase 1-2 randomized double-blind placebo-controlled trial enrolled 252 participants (210 vaccine/42 placebo; median age 23 years; 43% female) between 9 February 2015 and 26 May 2015. Vaccine recipients received ALVAC-HIV (vCP2438) alone at months 0 and 1 and with bivalent subtype C gp120/MF59 at months 3, 6, and 12.

Late boosting of the RV144 regimen with AIDSVAX B/E and ALVAC-HIV in HIV-uninfected Thai volunteers: a double-blind, randomised controlled trial.

Background: The RV144 phase 3 vaccine trial in Thailand demonstrated that ALVAC-HIV (vCP1521) and AIDSVAX B/E administration over 6 months resulted in a 31% efficacy in preventing HIV acquisition. In this trial, we assessed the immunological effect of an additional vaccine boost to the RV144 regimen at varying intervals between the priming vaccine series and the boost.

Methods: RV306 is a double-blind, placebo-controlled, randomised clinical trial done at three clinical sites in Thailand.