Publications by authors named "Johan van Hoof"

11 Publications

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Durable Humoral and Cellular Immune Responses Following Ad26.COV2.S Vaccination for COVID-19.

medRxiv 2021 Jul 7. Epub 2021 Jul 7.

Interim immunogenicity and efficacy data for the Ad26.COV2.S vaccine for COVID-19 have recently been reported . We describe here the 8-month durability of humoral and cellular immune responses in 20 individuals who received one or two doses of 5Ã-10 vp or 10 vp Ad26.COV2.S and in 5 participants who received placebo . We evaluated antibody and T cell responses on day 239, which was 8 months after the single-shot vaccine regimen (N=10) or 6 months after the two-shot vaccine regimen (N=10), although the present study was not powered to compare these regimens . We also report neutralizing antibody responses against the parental SARS-CoV-2 WA1/2020 strain as well as against the SARS-CoV-2 variants D614G, B.1.1.7 (alpha), B.1.617.1 (kappa), B.1.617.2 (delta), P.1 (gamma), B.1.429 (epsilon), and B.1.351 (beta).
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July 2021

Immunogenicity of Ad26.COV2.S vaccine against SARS-CoV-2 variants in humans.

Nature 2021 Jun 9. Epub 2021 Jun 9.

Janssen Vaccines & Prevention, Leiden, The Netherlands.

The Ad26.COV2.S vaccine has demonstrated clinical efficacy against symptomatic COVID-19, including against the B.1.351 variant that is partially resistant to neutralizing antibodies. However, the immunogenicity of this vaccine in humans against SARS-CoV-2 variants of concern remains unclear. Here we report humoral and cellular immune responses from 20 Ad26.COV2.S vaccinated individuals from the COV1001 phase I-IIa clinical trial against the original SARS-CoV-2 strain WA1/2020 as well as against the B.1.1.7, CAL.20C, P.1 and B.1.351 variants of concern. Ad26.COV2.S induced median pseudovirus neutralizing antibody titres that were 5.0-fold and 3.3-fold lower against the B.1.351 and P.1 variants, respectively, as compared with WA1/2020 on day 71 after vaccination. Median binding antibody titres were 2.9-fold and 2.7-fold lower against the B.1.351 and P.1 variants, respectively, as compared with WA1/2020. Antibody-dependent cellular phagocytosis, complement deposition and natural killer cell activation responses were largely preserved against the B.1.351 variant. CD8 and CD4 T cell responses, including central and effector memory responses, were comparable among the WA1/2020, B.1.1.7, B.1.351, P.1 and CAL.20C variants. These data show that neutralizing antibody responses induced by Ad26.COV2.S were reduced against the B.1.351 and P.1 variants, but functional non-neutralizing antibody responses and T cell responses were largely preserved against SARS-CoV-2 variants. These findings have implications for vaccine protection against SARS-CoV-2 variants of concern.
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June 2021

Safety and Efficacy of Single-Dose Ad26.COV2.S Vaccine against Covid-19.

N Engl J Med 2021 06 21;384(23):2187-2201. Epub 2021 Apr 21.

From Janssen Vaccines and Prevention, Leiden, the Netherlands (J. Sadoff, G. Shukarev, G. Scheper, M.L.G., H.S., J.V.H., M.D.); South African Research Council, Cape Town, South Africa (G.G.); Janssen Research and Development, Beerse, Belgium (A.V., C.T., H.F., B.S., K.O., M.F.R., N.C., T.T., K.H., J.R.G., F.S.); Janssen Research and Development, Spring House, PA (V.C.); Evandro Chagas National Institute of Infectious Diseases-Fiocruz, Rio de Janeiro (B.G.); the University of Alabama at Birmingham, Birmingham (P.A.G.); the National Institute of Allergy and Infectious Diseases, Rockville (K.L.T., M.A.M.), Walter Reed Army Institute of Research, Silver Spring (M.L.R.), and the Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore (K.M.N.) - all in Maryland; Biomedical Advanced Research and Development Authority, Washington, DC (J.T.); the Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston (D.H.B.); Janssen Research and Development, Raritan, NJ (J. Stoddard); and Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle (L.C.).

Background: The Ad26.COV2.S vaccine is a recombinant, replication-incompetent human adenovirus type 26 vector encoding full-length severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein in a prefusion-stabilized conformation.

Methods: In an international, randomized, double-blind, placebo-controlled, phase 3 trial, we randomly assigned adult participants in a 1:1 ratio to receive a single dose of Ad26.COV2.S (5×10 viral particles) or placebo. The primary end points were vaccine efficacy against moderate to severe-critical coronavirus disease 2019 (Covid-19) with an onset at least 14 days and at least 28 days after administration among participants in the per-protocol population who had tested negative for SARS-CoV-2. Safety was also assessed.

Results: The per-protocol population included 19,630 SARS-CoV-2-negative participants who received Ad26.COV2.S and 19,691 who received placebo. Ad26.COV2.S protected against moderate to severe-critical Covid-19 with onset at least 14 days after administration (116 cases in the vaccine group vs. 348 in the placebo group; efficacy, 66.9%; adjusted 95% confidence interval [CI], 59.0 to 73.4) and at least 28 days after administration (66 vs. 193 cases; efficacy, 66.1%; adjusted 95% CI, 55.0 to 74.8). Vaccine efficacy was higher against severe-critical Covid-19 (76.7% [adjusted 95% CI, 54.6 to 89.1] for onset at ≥14 days and 85.4% [adjusted 95% CI, 54.2 to 96.9] for onset at ≥28 days). Despite 86 of 91 cases (94.5%) in South Africa with sequenced virus having the 20H/501Y.V2 variant, vaccine efficacy was 52.0% and 64.0% against moderate to severe-critical Covid-19 with onset at least 14 days and at least 28 days after administration, respectively, and efficacy against severe-critical Covid-19 was 73.1% and 81.7%, respectively. Reactogenicity was higher with Ad26.COV2.S than with placebo but was generally mild to moderate and transient. The incidence of serious adverse events was balanced between the two groups. Three deaths occurred in the vaccine group (none were Covid-19-related), and 16 in the placebo group (5 were Covid-19-related).

Conclusions: A single dose of Ad26.COV2.S protected against symptomatic Covid-19 and asymptomatic SARS-CoV-2 infection and was effective against severe-critical disease, including hospitalization and death. Safety appeared to be similar to that in other phase 3 trials of Covid-19 vaccines. (Funded by Janssen Research and Development and others; ENSEMBLE number, NCT04505722.).
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June 2021

Immunogenicity of the Ad26.COV2.S Vaccine for COVID-19.

JAMA 2021 04;325(15):1535-1544

Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston, Massachusetts.

Importance: Control of the global COVID-19 pandemic will require the development and deployment of safe and effective vaccines.

Objective: To evaluate the immunogenicity of the Ad26.COV2.S vaccine (Janssen/Johnson & Johnson) in humans, including the kinetics, magnitude, and phenotype of SARS-CoV-2 spike-specific humoral and cellular immune responses.

Design, Setting, And Participants: Twenty-five participants were enrolled from July 29, 2020, to August 7, 2020, and the follow-up for this day 71 interim analysis was completed on October 3, 2020; follow-up to assess durability will continue for 2 years. This study was conducted at a single clinical site in Boston, Massachusetts, as part of a randomized, double-blind, placebo-controlled phase 1 clinical trial of Ad26.COV2.S.

Interventions: Participants were randomized to receive 1 or 2 intramuscular injections with 5 × 1010 viral particles or 1 × 1011 viral particles of Ad26.COV2.S vaccine or placebo administered on day 1 and day 57 (5 participants in each group).

Main Outcomes And Measures: Humoral immune responses included binding and neutralizing antibody responses at multiple time points following immunization. Cellular immune responses included immunospot-based and intracellular cytokine staining assays to measure T-cell responses.

Results: Twenty-five participants were randomized (median age, 42; age range, 22-52; 52% women, 44% male, 4% undifferentiated), and all completed the trial through the day 71 interim end point. Binding and neutralizing antibodies emerged rapidly by day 8 after initial immunization in 90% and 25% of vaccine recipients, respectively. By day 57, binding and neutralizing antibodies were detected in 100% of vaccine recipients after a single immunization. On day 71, the geometric mean titers of spike-specific binding antibodies were 2432 to 5729 and the geometric mean titers of neutralizing antibodies were 242 to 449 in the vaccinated groups. A variety of antibody subclasses, Fc receptor binding properties, and antiviral functions were induced. CD4+ and CD8+ T-cell responses were induced.

Conclusion And Relevance: In this phase 1 study, a single immunization with Ad26.COV2.S induced rapid binding and neutralization antibody responses as well as cellular immune responses. Two phase 3 clinical trials are currently underway to determine the efficacy of the Ad26.COV2.S vaccine.

Trial Registration: Identifier: NCT04436276.
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April 2021

A Double-Blind, Randomized, Placebo-Controlled Phase 1 Study of Ad26.ZIKV.001, an Ad26-Vectored Anti-Zika Virus Vaccine.

Ann Intern Med 2021 May 16;174(5):585-594. Epub 2021 Feb 16.

Beth Israel Deaconess Medical Center, Boston, Massachusetts (K.E.S., D.G.K., R.A.L., P.A., J.L., L.P., D.H.B.).

Background: Zika virus (ZIKV) may cause severe congenital disease after maternal-fetal transmission. No vaccine is currently available.

Objective: To assess the safety and immunogenicity of Ad26.ZIKV.001, a prophylactic ZIKV vaccine candidate.

Design: Phase 1 randomized, double-blind, placebo-controlled clinical study. ( NCT03356561).

Setting: United States.

Participants: 100 healthy adult volunteers.

Intervention: Ad26.ZIKV.001, an adenovirus serotype 26 vector encoding ZIKV M-Env, administered in 1- or 2-dose regimens of 5 × 10 or 1 × 10 viral particles (vp), or placebo.

Measurements: Local and systemic adverse events; neutralization titers by microneutralization assay (MN50) and T-cell responses by interferon-γ enzyme-linked immunospot and intracellular cytokine staining; and protectivity of vaccine-induced antibodies in a subset of participants through transfer in an exploratory mouse ZIKV challenge model.

Results: All regimens were well tolerated, with no safety concerns identified. In both 2-dose regimens, ZIKV neutralizing titers peaked 14 days after the second vaccination, with geometric mean MN50 titers (GMTs) of 1065.6 (95% CI, 494.9 to 2294.5) for 5 × 10 vp and 956.6 (595.8 to 1535.8) for 1 × 10 vp. Titers persisted for at least 1 year at a GMT of 68.7 (CI, 26.4-178.9) for 5 × 10 vp and 87.0 (CI, 29.3 to 258.6) for 1 × 10 vp. A 1-dose regimen of 1 × 10 vp Ad26.ZIKV.001 induced seroconversion in all participants 56 days after the first vaccination (GMT, 103.4 [CI, 52.7 to 202.9]), with titers persisting for at least 1 year (GMT, 90.2 [CI, 38.4 to 212.2]). Env-specific cellular responses were induced. Protection against ZIKV challenge was observed after antibody transfer from participants into mice, and MN50 titers correlated with protection in this model.

Limitation: The study was conducted in a nonendemic area, so it did not assess safety and immunogenicity in a flavivirus-exposed population.

Conclusion: The safety and immunogenicity profile makes Ad26.ZIKV.001 a promising candidate for further development if the need reemerges.

Primary Funding Source: Janssen Vaccines and Infectious Diseases.
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May 2021

Interim Results of a Phase 1-2a Trial of Ad26.COV2.S Covid-19 Vaccine.

N Engl J Med 2021 05 13;384(19):1824-1835. Epub 2021 Jan 13.

From Janssen Vaccines and Prevention, Leiden, the Netherlands (J. Sadoff, M.L.G., G. Shukarev, A.M.G., J. Stoop, S.T., E.C., G. Scheper, J. Hendriks, M.D., J.V.H., H.S.); Janssen Research and Development, Beerse (D.H., C.T., F.S.), Janssen Clinical Pharmacology Unit, Merksem (W.V.D.), the Center for Vaccinology, Ghent University, Gent (I.L.-R.), SGS Life Sciences (P.-J.B.) and the Center for the Evaluation of Vaccination, University of Antwerp (P.V.D.), Antwerp, and the Center for Clinical Pharmacology, University Hospitals Leuven, Leuven (J. de Hoon) - all in Belgium; Optimal Research, Melbourne, FL (M.K.); the Alliance for Multispecialty Research, Knoxville, TN (W.S.); the Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston (K.E.S., D.H.B.); and the Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle (S.C.D.R., K.W.C., M.J.M.).

Background: Efficacious vaccines are urgently needed to contain the ongoing coronavirus disease 2019 (Covid-19) pandemic of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A candidate vaccine, Ad26.COV2.S, is a recombinant, replication-incompetent adenovirus serotype 26 (Ad26) vector encoding a full-length and stabilized SARS-CoV-2 spike protein.

Methods: In this multicenter, placebo-controlled, phase 1-2a trial, we randomly assigned healthy adults between the ages of 18 and 55 years (cohort 1) and those 65 years of age or older (cohort 3) to receive the Ad26.COV2.S vaccine at a dose of 5×10 viral particles (low dose) or 1×10 viral particles (high dose) per milliliter or placebo in a single-dose or two-dose schedule. Longer-term data comparing a single-dose regimen with a two-dose regimen are being collected in cohort 2; those results are not reported here. The primary end points were the safety and reactogenicity of each dose schedule.

Results: After the administration of the first vaccine dose in 805 participants in cohorts 1 and 3 and after the second dose in cohort 1, the most frequent solicited adverse events were fatigue, headache, myalgia, and injection-site pain. The most frequent systemic adverse event was fever. Systemic adverse events were less common in cohort 3 than in cohort 1 and in those who received the low vaccine dose than in those who received the high dose. Reactogenicity was lower after the second dose. Neutralizing-antibody titers against wild-type virus were detected in 90% or more of all participants on day 29 after the first vaccine dose (geometric mean titer [GMT], 212 to 354), regardless of vaccine dose or age group, and reached 96% by day 57 with a further increase in titers (GMT, 288 to 488) in cohort 1a. Titers remained stable until at least day 71. A second dose provided an increase in the titer by a factor of 2.6 to 2.9 (GMT, 827 to 1266). Spike-binding antibody responses were similar to neutralizing-antibody responses. On day 15, CD4+ T-cell responses were detected in 76 to 83% of the participants in cohort 1 and in 60 to 67% of those in cohort 3, with a clear skewing toward type 1 helper T cells. CD8+ T-cell responses were robust overall but lower in cohort 3.

Conclusions: The safety and immunogenicity profiles of Ad26.COV2.S support further development of this vaccine candidate. (Funded by Johnson & Johnson and the Biomedical Advanced Research and Development Authority of the Department of Health and Human Services; COV1001 number, NCT04436276.).
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May 2021

Single-shot Ad26 vaccine protects against SARS-CoV-2 in rhesus macaques.

Nature 2020 10 30;586(7830):583-588. Epub 2020 Jul 30.

Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.

A safe and effective vaccine for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may be required to end the coronavirus disease 2019 (COVID-19) pandemic. For global deployment and pandemic control, a vaccine that requires only a single immunization would be optimal. Here we show the immunogenicity and protective efficacy of a single dose of adenovirus serotype 26 (Ad26) vector-based vaccines expressing the SARS-CoV-2 spike (S) protein in non-human primates. Fifty-two rhesus macaques (Macaca mulatta) were immunized with Ad26 vectors that encoded S variants or sham control, and then challenged with SARS-CoV-2 by the intranasal and intratracheal routes. The optimal Ad26 vaccine induced robust neutralizing antibody responses and provided complete or near-complete protection in bronchoalveolar lavage and nasal swabs after SARS-CoV-2 challenge. Titres of vaccine-elicited neutralizing antibodies correlated with protective efficacy, suggesting an immune correlate of protection. These data demonstrate robust single-shot vaccine protection against SARS-CoV-2 in non-human primates. The optimal Ad26 vector-based vaccine for SARS-CoV-2, termed Ad26.COV2.S, is currently being evaluated in clinical trials.
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October 2020

Developing Vaccines for SARS-CoV-2 and Future Epidemics and Pandemics: Applying Lessons from Past Outbreaks.

Health Secur 2020 May/Jun;18(3):241-249. Epub 2020 Apr 29.

Sabrina Ivol is Senior Specialist, Policy; and Johan Van Hoof, MD, is Managing Director; both with Janssen Vaccines & Prevention BV, Janssen Pharmaceuticals R&D, Leiden, Netherlands.

The COVID-19 pandemic is a stark reminder of the heavy toll that emerging infectious diseases (EIDs) with epidemic and pandemic potential can inflict. Vaccine development, scale-up, and commercialization is a long, expensive, and risky enterprise that requires substantial upfront planning and offers no guarantee of success. EIDs are a particularly challenging target for global health preparedness, including for vaccine development. Insufficient attention has been given to challenges, lessons learned, and potential solutions to support and sustain vaccine industry engagement in vaccine development for EIDs. Drawing from lessons from the most recent Ebola epidemic in the Democratic Republic of the Congo, as well as the 2009 H1N1 influenza, 2014-2016 Ebola, and 2015-16 Zika outbreaks preceding it, we offer our perspective on challenges facing EID vaccine development and recommend additional solutions to prioritize in the near term. The 6 recommendations focus on reducing vaccine development timelines and increasing business certainty to reduce risks for companies. The global health security community has an opportunity to build on the current momentum to design a sustainable model for EID vaccines.
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July 2020

Safety and Immunogenicity of Novel Adenovirus Type 26- and Modified Vaccinia Ankara-Vectored Ebola Vaccines: A Randomized Clinical Trial.

JAMA 2016 Apr;315(15):1610-23

Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom7National Institute for Health Research (NIHR) Oxford Biomedical Research Centre, Oxford, United Kingdom.

Importance: Developing effective vaccines against Ebola virus is a global priority.

Objective: To evaluate an adenovirus type 26 vector vaccine encoding Ebola glycoprotein (Ad26.ZEBOV) and a modified vaccinia Ankara vector vaccine, encoding glycoproteins from Ebola virus, Sudan virus, Marburg virus, and Tai Forest virus nucleoprotein (MVA-BN-Filo).

Design, Setting, And Participants: Single-center, randomized, placebo-controlled, observer-blind, phase 1 trial performed in Oxford, United Kingdom, enrolling healthy 18- to 50-year-olds from December 2014; 8-month follow-up was completed October 2015.

Interventions: Participants were randomized into 4 groups, within which they were simultaneously randomized 5:1 to receive study vaccines or placebo. Those receiving active vaccines were primed with Ad26.ZEBOV (5 × 10(10) viral particles) or MVA-BN-Filo (1 × 10(8) median tissue culture infective dose) and boosted with the alternative vaccine 28 or 56 days later. A fifth, open-label group received Ad26.ZEBOV boosted by MVA-BN-Filo 14 days later.

Main Outcomes And Measures: The primary outcomes were safety and tolerability. All adverse events were recorded until 21 days after each immunization; serious adverse events were recorded throughout the trial. Secondary outcomes were humoral and cellular immune responses to immunization, as assessed by enzyme-linked immunosorbent assay and enzyme-linked immunospot performed at baseline and from 7 days after each immunization until 8 months after priming immunizations.

Results: Among 87 study participants (median age, 38.5 years; 66.7% female), 72 were randomized into 4 groups of 18, and 15 were included in the open-label group. Four participants did not receive a booster dose; 67 of 75 study vaccine recipients were followed up at 8 months. No vaccine-related serious adverse events occurred. No participant became febrile after MVA-BN-Filo, compared with 3 of 60 participants (5%; 95% CI, 1%-14%) receiving Ad26.ZEBOV in the randomized groups. In the open-label group, 4 of 15 Ad26.ZEBOV recipients (27%; 95% CI, 8%-55%) experienced fever. In the randomized groups, 28 of 29 Ad26.ZEBOV recipients (97%; 95% CI, 82%- 99.9%) and 7 of 30 MVA-BN-Filo recipients (23%; 95% CI, 10%-42%) had detectable Ebola glycoprotein-specific IgG 28 days after primary immunization. All vaccine recipients had specific IgG detectable 21 days postboost and at 8-month follow-up. Within randomized groups, at 7 days postboost, at least 86% of vaccine recipients showed Ebola-specific T-cell responses.

Conclusions And Relevance: In this phase 1 study of healthy volunteers, immunization with Ad26.ZEBOV or MVA-BN-Filo did not result in any vaccine-related serious adverse events. An immune response was observed after primary immunization with Ad26.ZEBOV; boosting by MVA-BN-Filo resulted in sustained elevation of specific immunity. These vaccines are being further assessed in phase 2 and 3 studies.

Trial Registration: Identifier: NCT02313077.
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April 2016