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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.Results: Baseline-seropositive placebo recipients with higher average titer had lower instantaneous risk of HVCD-Any in 2- to 16-year-olds and in 9- to 16-year-olds (HR, 0.26 or 0.15 per 10-fold increase in average titer by 2 methods [95% confidence interval {CI}, .14-.45 and .07-.34, respectively]) pooled across both trials. Results were similar for homologous HVCD. There was evidence suggesting increased HVCD-Any risk in participants with low average titer (1:10 to 1:100) compared to seronegative participants (HR, 1.85 [95% CI, .93-3.68]).Conclusions: Natural infection-induced nAbs were inversely associated with hospitalized dengue, upon exceeding a relatively low threshold. [ABSTRACT FROM AUTHOR]

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. Results Baseline and M13 geometric mean PRNT50 titers were greater in 18–45-y-olds and in 46–50-y-olds vs 9–16-y-olds for most comparisons. Estimated VE (95% CIs against VCD-DENV-AnyM0→M25 ranged from 75.3% to 90.9% (52.5% to 100%) for 18–45-y-olds and 74.8% to 92.0% (53.4% to 100%) for 46–50-y-olds. Estimated VE (95% CIs) against HVCD-DENV-AnyM0→M72 ranged from 58.8% to 78.1% (40.9 to 98.9%) for 18–45-y-olds and 57.2% to 78.4% (40.5 to 97.6%) for 46–50-y-olds. Corresponding predictions among baseline-seropositive individuals yielded comparable or higher VE estimates. Conclusions VE M0→M25 against DENV-Any and VE against HVCD-DENV-AnyM0→M72 are both expected to be higher in 18–45 and 46–50-y-olds vs CYD14 and CYD15 9–16-y-olds. [ABSTRACT FROM AUTHOR]

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. We estimated efficacy in individuals with monotypic or multitypic immune profiles. Methods Participants enrolled in the immunogenicity subsets of 2 randomized placebo-controlled phase 3 studies (CYD14, NCT01373281; CYD15, NCT01374516) were classified as either monotypic or multitypic, based on measured baseline dengue plaque reduction neutralization test. Vaccine efficacy (VE) against symptomatic virologically confirmed dengue (VCD) was assessed over 25 months and against VCD hospitalization over 6 years. Results Of 3927 participants in the immunogenicity subsets, 496 and 257 in the CYD-TDV and placebo groups, respectively, were classified as monotypic immune, and 1227 and 612, respectively, as multitypic immune. VE against symptomatic VCD was 77.4% (95% CI, 56.4%–88.2%) for monotypic and 89.2% (95% CI, 71.5%–95.9%) for multitypic profiles, with corresponding absolute risk reductions (ARRs) of 4.48% (95% CI, 2.32%–6.65%) for monotypics and 1.67% (95% CI,.89%–2.46%) for multitypics. VE against hospitalized VCD was 75.3% (95% CI, 42.7%–90.2%) in monotypics and 81.2% (95% CI, 21.7%–96.8%) in multitypics, with ARRs of 0.95% (95% CI,.37%–1.53%) for monotypics and 0.18% (95% CI,.02%–.34%) for multitypics. Conclusions CYD-TDV benefits individuals with monotypic and multitypic immune profiles. Larger public health benefit is expected to derive from the protection of individuals with a monotypic immune profile. [ABSTRACT FROM AUTHOR]

Background: The RV144 ALVAC-HIV prime, AIDSVAX B/E boost afforded 60% efficacy against human immunodeficiency virus (HIV) acquisition at 1 year, waning to 31.2% after 3.5 years. We hypothesized that additional vaccinations might augment immune correlates of protection.Methods: In a randomized placebo-controlled double-blind study of 162 HIV-negative RV144 vaccine recipients, we evaluated 2 additional boosts, given 6-8 years since RV144 vaccination, for safety and immunogenicity, at weeks 0 and 24. Study groups 1-3 received ALVAC-HIV+AIDSVAX B/E, AIDSVAX B/E, and ALVAC-HIV, respectively, or placebo.Results: Vaccines were well tolerated. For groups 1 and 2, plasma immunoglobulin (Ig) G, IgA, and neutralizing antibody responses at week 2 were all significantly higher than 2 weeks after the last RV144 vaccination. IgG titers against glycoprotein (gp) 70V1V2 92TH023 increased 14-fold compared with 2 weeks after the last RV144 vaccination (14069 vs 999; P < .001). Groups 1 and 2 did not differ significantly from each other, whereas group 3 was similar to placebo recipients. Responses in groups 1 and 2 declined by week 24 but were boosted by the second vaccination, albeit at lower magnitude than for week 2.Conclusions: In RV144 vaccinees, AIDSVAX B/E with or without ALVAC-HIV 6-8 years after initial vaccination generated higher humoral responses than after RV144, but these responses were short-lived, and their magnitude did not increase with subsequent boost.Clinical Trials Registration: NCT01435135. [ABSTRACT FROM AUTHOR]

We characterize the breadth, function and phenotype of innate and adaptive cellular responses in a prevention of Mycobacterium tuberculosis infection trial. Responses are measured by whole blood intracellular cytokine staining at baseline and 70 days after vaccination with H4:IC31 (subunit vaccine containing Ag85B and TB10.4), Bacille Calmette-Guerin (BCG, a live attenuated vaccine) or placebo (n = ~30 per group). H4:IC31 vaccination induces Ag85B and TB10.4-specific CD4 T cells, and an unexpected NKTlike subset, that expresses IFN-γ, TNF and/or IL-2. BCG revaccination increases frequencies of CD4 T cell subsets that either express Th1 cytokines or IL-22, and modestly increases IFNγ-producing NK cells. In vitro BCG re-stimulation also triggers responses by donor-unrestricted T cells, which may contribute to host responses against mycobacteria. BCG, which demonstrated efficacy against sustained Mycobacterium tuberculosis infection, modulates multiple immune cell subsets, in particular conventional Th1 and Th22 cells, which should be investigated in discovery studies of correlates of protection. Virginie Rozot and Elisa Nemes et al. report comprehensive profiling of immune responses from participants in a recent clinical trial of the H4:IC31 and BCG vaccines against Mycobacterium tuberculosis infection. Using a novel analysis platform, they uncover complex vaccine-induced modulation of different immune cell subsets. [ABSTRACT FROM AUTHOR]

An abstract of the article "HVTN 097: Evaluation of the RV144 Vaccine Regimen in HIV Uninfected South African Adults" by Glenda E. Gray, Erica Andersen-Nissen, Fatima Laher and colleagues is presented.

A letter to the editor is presented which estimates the prevalence of deep vein thrombosis in chronically bedridden elderly individuals.

A letter to the editor is presented in response to the article about bacteremia.

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 12.5 vs. month 6.5, but waned by month 18, we investigated vaccine-elicited immune responses after a month 30 boost in this study, HVTN 100 Part B. From 13 September 2017 to 7 August 2018, a subgroup of vaccinees was randomized to receive intramuscular injections of ALVAC+gp120/MF59 (n = 32) or gp120/MF59 alone (n = 31) and a subgroup of placebo recipients was administered placebo (n = 7) at month 30. Primary outcomes were safety, IgG binding antibodies (bAbs) to vaccine-specific and V1V2 Env proteins and vaccine-specific CD4+ T cells at month 30.5. Secondary outcomes included neutralizing and antibody dependent cellular cytotoxicity functions and durability at months 30 and 36. Both vaccine groups had an acceptable safety profile. There were no statistically significant differences in the occurrence or level of IgG bAbs between the vaccine boost groups for any vaccine-specific or V1V2 antigens. IgG responses were higher to vaccine-matched gp120 than to V1V2. The booster vaccination restored the magnitude-breadth IgG bAb response to V1V2 antigens at month 30.5. However, it rapidly waned by month 36. CD4+ T-cell response rates to the 3 vaccine-matched Env antigens for the combined vaccine groups ranged from 37% at month 30, boosted to as high as 91% at month 30.5, and waned by month 36 to as low as 44%, with no significant differences between the vaccine boost groups. Because these responses waned after 6 months, additional strategies may be needed to maintain the durability of prime-boost vaccine regimens and to generate these or other immune responses that confer protection. Trial registration: South African National Clinical Trials Register (SANCTR number: DOH-27-0215-4796) and ClinicalTrials.gov (NCT02404311)., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: The HVTN 100 clinical trial was funded by the National Institute of Allergy and Infectious Diseases (NIAID, https://www.niaid.nih.gov/) U.S. Public Health Service Grants UM1 AI068614 [LOC: HIV Vaccine Trials Network], UM1 AI068618 [LC: HIV Vaccine Trials Network], and UM1 AI068635 [SDMC: HIV Vaccine Trials Network], UM1 AI069453 [Soweto-Bara Clinical Research Site], UM1 AI069519 [Cape Town – Emavundleni Clinical Research Site], UM1 AI069469 [Durban –eThekwini Clinical Research Site], and UM1 AI069422 [Durban – Isipingo Clinical Research Site] and NIH (P30 AI064518). Dr Naicker was supported by a Scientific Leadership Development award from HVTN. The HVTN 100 clinical trial was also funded by the Bill & Melinda Gates Foundation award OPP1110792. The Gates Foundation provided funding to Fred Hutchinson Cancer Center to support the implementation of HVTN 100 at the Soweto-Bara Clinical Research Site, Cape Town-Emavundleni Clinical Research Site, Durban-eThekwini Clinical Research Site, and Durban-Isipingo Clinical Research Site, as well as the Klerksdorp and Soshanguve sites. Funding was provided to Novartis Vaccines and Diagnostics (now part of the GlaxoSmithKline group of companies) by NIAID (HHSN272201300033C//HHSN272201600012C) for the selection and process development of the two gp120 envelope proteins TV1.C and 1086.C, and by the Bill & Melinda Gates Foundation Global Health Grant OPP1017604 and NIAID for the manufacture and release of the gp120 clinical grade material. Role of the funding source: Within the terms of the Grant Award of the Cooperative Agreement with the HIV Vaccine Trials Network (HVTN), the study sponsor, NIAID, contributed to, reviewed, and approved the HVTN 100 study design, contributed to the review and analysis of data, concurred with the decision to publish, and assisted with the preparation of the manuscript. The Gates Foundation contributed to, reviewed, and approved the HVTN 100 study design, and reviewed the data from the study. Neither NIAID or the Gates Foundation were involved in the data collection, and did not perform statistical analyses. GlaxoSmithKline Biologicals SA was provided the opportunity to review a preliminary version of this manuscript, but the authors are solely responsible for final content and interpretation. MK is employed by and holds shares in GSK. All other authors have nothing to declare., (Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.)

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.1.351 [beta] variant spike protein) or placebo. Symptomatic COVID-19 was defined as laboratory-confirmed COVID-19 with COVID-19-like illness (CLI) symptoms. The primary efficacy endpoint was the prevention of symptomatic COVID-19 ≥14 days after the second injection (post-dose 2 [PD2])., Results: Between 19 Oct 2021 and 15 Feb 2022, 12,924 participants received ≥1 study injection. 75% of participants were SARS-CoV-2 non-naïve. 11,416 participants received both study injections (efficacy-evaluable population [vaccine, n=5,736; placebo, n=5,680]). Up to 15 March 2022, 121 symptomatic COVID-19 cases were reported (32 in the vaccine group and 89 in the placebo group) ≥14 days PD2 with a vaccine efficacy (VE) of 64.7% (95% confidence interval [CI] 46.6; 77.2%). VE was 75.1% (95% CI 56.3; 86.6%) in non-naïve and 30.9% (95% CI -39.3; 66.7%) in naïve participants. Viral genome sequencing identified the infecting strain in 68 cases (Omicron [BA.1 and BA.2 subvariants]: 63; Delta: 4; Omicron and Delta: 1). The vaccine was well-tolerated and had an acceptable safety profile., Conclusions: A bivalent vaccine conferred heterologous protection against symptomatic infection with newly emergent Omicron (BA.1 and BA.2) in non-naïve adults 18-59 years of age., Competing Interests: Declaration of interests GHD, MIB, BF, M-HG, CAG, RMC, SS are Sanofi employees. MIB, BF, M-HG, CAG, RMC, SS hold stock or stock options in Sanofi. SS hold patents pending on COVID-19 vaccine. RMC has Received institutional funding from BARDA for the present study; has received support for attending meetings and/or travel from Sanofi; and holds patents planned, issued or pending from Sanofi. M-HG has received payment or honoraria for lectures, presentations, speakers’ bureaus, manuscript writing or educational events from Sanofi. NR has received institutional funding from the National Institutes of Health; and institutional grants or contracts from Merck, Sanofi, Quidel, Pfizer and Lilly. SRW has received institutional funding from Sanofi and the National Institute of Allergy and Immunology/National Institutes of Health; and institutional grants or contracts from Janssen Vaccines/Johnson & Johnson, Moderna Tx, Vir Biotechnology and Worcester HIV vaccine; has participated on data safety monitoring or advisory boards for Janssen Vaccines/Johnson & Johnson; and his spouse holds stock/stock options in Regeneron Pharmaceuticals. NG has received institutional funding from Sanofi, GSK and the National Institute of Allergy and Immunology/National Institutes of Health; and is in receipt of grants or contracts from the NIH/NIAID/DAIDS. MA is an employee of the NIAID, which funded aspects of the current study. MAC and MK are employees of GSK and owns shares in the GSK group of companies. LS is an employee of the GSK group of companies. MJ and JJK have received institutional support from Sanofi and the NIAID/NIH with respect to this study. MLR has received institutional support/contracts for the present manuscript from WRAIR IPA and the US Medical Research and Development Command. MA is an employee of the NIAID, which funded aspects of the current study; The NIAID provides grant funding to the HIV Vaccine Trials Network (HVTN) Leadership and Operations Center (UM1 AI 68614HVTN), the Statistics and Data Management Center (UM1 AI 68635), the HVTN Laboratory Center (UM1 AI 68618), the HIV Prevention Trials Network Leadership and Operations Center (UM1 AI 68619), the AIDS Clinical Trials Group Leadership and Operations Center (UM1 AI 68636), and the Infectious Diseases Clinical Research Consortium leadership group 5 (UM1 AI 148684-03). SSa was a Sanofi employee at the time of study conduct; and holds patents planned, issued of pending on COVID-19 vaccines. AC, JA KPA, ASB, TB, DD, MKJ, HK, RM, NM, HR, SMVM, FS, JT, TAW, SG have no interests to declare.