We conducted a randomized, Phase 2 trial to assess the safety and humoral immunogenicity of reduced doses/dose volume of the standard dose of Ad26.COV2.S COVID-19 vaccine (5 × 1010 viral particles [vp]) in healthy adolescents aged 12–17 years. Participants were randomly assigned to receive Ad26.COV2.S at reduced dose levels of 0.625 × 1010 (0.5 mL), 1.25 × 1010 (0.5 mL) or 2.5 × 1010 (0.5 mL or low volume 0.25 mL) vp in a 1- or 2-dose (56-day interval) primary schedule. Adolescents who received a 1-dose primary schedule received a 2.5 × 1010 vp booster dose 6 months later. Safety and humoral immunogenicity were assessed up to 6 months post-last vaccination. All regimens were well tolerated, with no safety concerns identified. Local and systemic solicited AEs in adolescents were consistent with the known safety profile in adults. All 1- and 2-dose Ad26.COV2.S primary schedules elicited robust peak Spike-binding antibody responses and virus neutralizing titers against the reference strain, in participants with and without preexisting SARS-CoV-2 immunity. Immune responses were durable for at least 6 months. Spike-binding antibody responses were comparable to those elicited in young adults aged 18–25 years who received a standard dose of Ad26.COV2.S in Phase 3 efficacy studies Reduced doses/dose volume of Ad26.COV2.S had an acceptable safety profile and elicited robust humoral immune responses in adolescents aged 12–17 years. All 1- and 2-dose schedules elicited Spike-binding antibody responses that were comparable to an adult population in whom efficacy has been demonstrated using a higher vaccine dose. (clinicaltrials.gov NCT05007080).

Background Vaccine co-administration can increase vaccination coverage. We assessed the safety, reactogenicity, and immunogenicity of concomitant administration of Ad26.COV2.S COVID-19 vaccine with seasonal influenza vaccines. Methods This non-inferiority, Phase 3, randomised, double-blind study enrolled 859 healthy adults and was conducted between 02 November 2021 and 28 November 2022. Participants aged >= 18 - 64 years were randomised to receive a seasonal quadrivalent standard dose (SD) influenza vaccine ( A fl uria Quadrivalent, Seqirus) concomitantly with Ad26.COV2.S (Coad_SD) or placebo (0.9% NaCl; Control_SD) on Day 1 and placebo or Ad26.COV2.S on Day 29. Participants aged >= 65-years were randomised to the Coad_SD or Control_SD groups, or to Coad_HD or Control_HD groups that received a seasonal quadrivalent HD (high-dose) influenza vaccine ( Fluzone High-Dose Quadrivalent, Sanofi Pasteur Inc) in the same schedules. The primary outcomes were haemagglutinin inhibition titres against the four influenza vaccine strains at Day 29, and SARS-CoV-2 Spike- specific antibodies at Day 29 in the Coad_SD group and Day 57 in the Control-SD group, with a non-inferiority margin (Control-SD group/Coad_SD group) of 1.5. Reactogenicity and safety were assessed in all participants (NCT05091307). Findings Non-inferiority criteria for concomitant administration in the SD groups were met for SARS-CoV-2 Spike- specific antibodies (ratio 1.11, 95% CI 0.97-1.26) and haemagglutinin inhibition titres for all influenza strains (A/H3N2 1.23, 95% CI 1.05-1.45;B/Victoria 0.99, 95% CI 0.84-1.19; B/Yamagata, 1.03, 95% CI 0.88-1.21) except A/H1N1 (1.28, 95% CI 1.09-1.53) for which the upper limit of the 95% CI was >1.5. Concomitant administration of Ad26.COV2.S and SD influenza vaccine induced robust immune responses in terms of SARS-CoV-2 Spike- specific antibodies and haemagglutinin inhibition to all four influenza strains. Seroconversion and seroprotection rates against all influenza vaccine strains were comparable in the Coad and Control groups. Anti-Spike antibodies 28 days after receiving Ad26.COV2.S were similar whether administered with influenza vaccine or alone. Antibody responses persisted at least 6 months post-vaccination in all groups. The reactogenicity and safety profile following co-administration was consistent with the known safety profiles of the study vaccines. No safety concerns were identified. Coadministration was immunogenic and well tolerated in adults aged >= 65 years who received HD influenza vaccine. Interpretation Co-administration of seasonal influenza vaccine with Ad26.COV2.S was immunogenic with an acceptable safety profile, supporting co-administration of these vaccines. FundingJanssen Vaccines & Prevention BV and Biomedical Advanced Research and Development Authority. Copyright (c) 2024 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license(http://creativecommons.org/licenses/by/4.0/).

BACKGROUND:Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare adverse event identified following vaccination with some adenovirus-vectored COVID-19 vaccines, including Ad26.COV2.S. VITT is characterized by the presence of antibodies against platelet factor 4 (PF4). OBJECTIVES:To evaluate whether PF4 antibodies were generally induced following vaccination with adenovirus type 26 (Ad26)-vectored vaccines. METHODS:The study included 913 and 991 healthy participants without thromboembolic (TE) events in Ad26.COV2.S and non-COVID-19 Ad26-vectored vaccine clinical studies, respectively, and 1 participant with VITT following Ad26.COV2.S vaccination. PF4 antibody levels were measured in prevaccination and postvaccination sera. PF4 antibody positivity rates were assessed in a case-control setting in participants who developed TE events during participation in Ad26-vectored vaccine clinical studies. RESULTS:In the 1 VITT patient, PF4 antibodies were negative before vaccination. Seroconversion for platelet-activating PF4 antibodies was observed upon Ad26.COV2.S vaccination. In participants without TE events, the PF4 antibody levels and positivity rates were similar before and after Ad26 vaccination. Ad26 vaccination did not increase PF4 antibody levels in participants who were PF4 antibody-positive at baseline (n = 47). Lastly, 1 out of 28 TE cases and 2 out of 156 non-TE controls seroconverted after Ad26.COV2.S vaccination. None of the 15 TE cases and 3 of the 77 non-TE controls seroconverted following non-COVID-19 Ad26 vaccination. CONCLUSION:Ad26.COV2.S and the other Ad26-vectored vaccines studied did not generally induce PF4 antibodies or increase preexisting PF4 antibody levels. Moreover, unlike VITT, TE events that occurred at any time following Ad26 vaccination were not associated with PF4 antibodies.

2.5 x 10(10) vp Ad26.COV2.S elicited robust SARS-CoV-2-specific antibody responses in adolescents through 6 months, with acceptable safety and reactogenicity profiles. Compared with adults immunized with 5 x 10(10) vp Ad26.COV2.S, adolescents had higher antibody levels, despite being vaccinated with a lower dose.

Background: This study aimed to support the end-of-shelf life specification (2.5 × 1010 virus particles [vp]) for the standard Ad26.COV2.S dose (5 × 1010 vp). Methods: This randomized, double-blind Phase 3 study evaluated immunogenicity, reactogenicity, and safety of several Ad26.COV2.S dose levels (range 1.25 to 9 × 1010 vp) in 1593 adults between June 2021 and July 2023. Results: Spike-binding antibody responses 28 days post-dose 1 were non-inferior for the 9 × 1010 vp, but not the 2.5 × 1010 vp group when compared with the standard dose. Non-inferiority was demonstrated in terms of spike-binding antibody responses 14 days post-dose 2 for each dose level, including the lowest dose level of 1.25 × 1010 vp, compared to 28 days after one dose and 14 days after two doses of the standard dose. Spike-binding antibody levels correlated well with virus neutralizing titers. There was no impact of pre-existing Ad26.COV2.S neutralizing titers on immunogenicity at any dose level. All dose levels were well tolerated. Conclusions: This study highlights the challenges associated with conducting clinical studies in a rapidly evolving environment and underscores the importance of platform data that can guide initial vaccine specifications such as shelf life during accelerated vaccine development. The present study supports the end-of-shelf life specifications for the approved Ad26.COV2.S dose, and could provide useful information in future vaccine developments using adenovirus vector vaccines.

BACKGROUND:Ad26.COV2.S is a well-tolerated and effective vaccine against COVID-19. We evaluated durability of anti-SARS-CoV-2 antibodies elicited by single-dose Ad26.COV2.S and the impact of boosting. METHODS:In randomized, double-blind, placebo-controlled, phase 1/2a and phase 2 trials, participants received single-dose Ad26.COV2.S (5 × 1010 viral particles [vp]) followed by booster doses of 5 × 1010 vp or 1.25 × 1010 vp. Neutralizing antibody levels were determined by a virus neutralization assay (VNA) approximately 8-9 months after dose 1. Binding and neutralizing antibody levels were evaluated by an enzyme-linked immunosorbent assay and pseudotyped VNA 6 months after dose 1 and 7 and 28 days after boosting. RESULTS:Data were analyzed from phase 1/2a participants enrolled from 22 July-18 December 2020 (Cohort 1a, 18-55 years [y], N = 25; Cohort 2a, 18-55y, N = 17; Cohort 3, ≥65y, N = 22), and phase 2 participants from 14 to 22 September 2020 (18-55y and ≥ 65y, N = 73). Single-dose Ad26.COV2.S elicited stable neutralizing antibodies for at least 8-9 months and stable binding antibodies for at least 6 months, irrespective of age. A 5 × 1010 vp 2-month booster dose increased binding antibodies by 4.9- to 6.2-fold 14 days post-boost versus 28 days after initial immunization. A 6-month booster elicited a steep and robust 9-fold increase in binding antibody levels 7 days post-boost. A 5.0-fold increase in neutralizing antibodies was observed by 28 days post-boost for the Beta variant. A 1.25 × 1010 vp 6-month booster elicited a 3.6-fold increase in binding antibody levels at 7 days post-boost versus pre-boost, with a similar magnitude of post-boost responses in both age groups. CONCLUSIONS:Single-dose Ad26.COV2.S elicited durable antibody responses for at least 8 months and elicited immune memory. Booster-elicited binding and neutralizing antibody responses were rapid and robust, even with a quarter vaccine dose, and stronger with a longer interval since primary vaccination. TRIAL REGISTRATION:ClinicalTrials.gov Identifier: NCT04436276, NCT04535453.

BACKGROUND:Despite the availability of effective vaccines against COVID-19, booster vaccinations are needed to maintain vaccine-induced protection against variant strains and breakthrough infections. This study aimed to investigate the efficacy, safety, and immunogenicity of the Ad26.COV2.S vaccine (Janssen) as primary vaccination plus a booster dose. METHODS:ENSEMBLE2 is a randomised, double-blind, placebo-controlled, phase 3 trial including crossover vaccination after emergency authorisation of COVID-19 vaccines. Adults aged at least 18 years without previous COVID-19 vaccination at public and private medical practices and hospitals in Belgium, Brazil, Colombia, France, Germany, the Philippines, South Africa, Spain, the UK, and the USA were randomly assigned 1:1 via a computer algorithm to receive intramuscularly administered Ad26.COV2.S as a primary dose plus a booster dose at 2 months or two placebo injections 2 months apart. The primary endpoint was vaccine efficacy against the first occurrence of molecularly confirmed moderate to severe-critical COVID-19 with onset at least 14 days after booster vaccination, which was assessed in participants who received two doses of vaccine or placebo, were negative for SARS-CoV-2 by PCR at baseline and on serology at baseline and day 71, had no major protocol deviations, and were at risk of COVID-19 (ie, had no PCR-positive result or discontinued the study before day 71). Safety was assessed in all participants; reactogenicity, in terms of solicited local and systemic adverse events, was assessed as a secondary endpoint in a safety subset (approximately 6000 randomly selected participants). The trial is registered with ClinicalTrials.gov, NCT04614948, and is ongoing. FINDINGS:Enrolment began on Nov 16, 2020, and the primary analysis data cutoff was June 25, 2021. From 34 571 participants screened, the double-blind phase enrolled 31 300 participants, 14 492 of whom received two doses (7484 in the Ad26.COV2.S group and 7008 in the placebo group) and 11 639 of whom were eligible for inclusion in the assessment of the primary endpoint (6024 in the Ad26.COV2.S group and 5615 in the placebo group). The median (IQR) follow-up post-booster vaccination was 36·0 (15·0-62·0) days. Vaccine efficacy was 75·2% (adjusted 95% CI 54·6-87·3) against moderate to severe-critical COVID-19 (14 cases in the Ad26.COV2.S group and 52 cases in the placebo group). Most cases were due to the variants alpha (B.1.1.7) and mu (B.1.621); endpoints for the primary analysis accrued from Nov 16, 2020, to June 25, 2021, before the global dominance of delta (B.1.617.2) or omicron (B.1.1.529). The booster vaccine exhibited an acceptable safety profile. The overall frequencies of solicited local and systemic adverse events (evaluated in the safety subset, n=6067) were higher among vaccine recipients than placebo recipients after the primary and booster doses. The frequency of solicited adverse events in the Ad26.COV2.S group were similar following the primary and booster vaccinations (local adverse events, 1676 [55·6%] of 3015 vs 896 [57·5%] of 1559, respectively; systemic adverse events, 1764 [58·5%] of 3015 vs 821 [52·7%] of 1559, respectively). Solicited adverse events were transient and mostly grade 1-2 in severity. INTERPRETATION:A homologous Ad26.COV2.S booster administered 2 months after primary single-dose vaccination in adults had an acceptable safety profile and was efficacious against moderate to severe-critical COVID-19. Studies assessing efficacy against newer variants and with longer follow-up are needed. FUNDING:Janssen Research & Development.

Background Despite the availability of effective vaccines against coronavirus disease 2019 (Covid-19), the emergence of variant strains and breakthrough infections pose a challenging new reality. Booster vaccinations are needed to maintain vaccine-induced protection. Methods ENSEMBLE2 is an ongoing, randomized, double-blind, placebo-controlled, phase 3 pivotal trial including crossover vaccination after emergency authorization of Covid-19 vaccines. Adults aged ≥18 years were randomized to receive Ad26.COV2.S or placebo as a primary dose plus a booster dose at two months. The primary endpoint was vaccine efficacy against the first occurrence of molecularly-confirmed moderate to severe–critical Covid-19 with onset ≥14 days after booster vaccination in the per-protocol population. Key efficacy, safety, and immunogenicity endpoints were also assessed. Results The double-blind phase enrolled 31,300 participants, 14,492 of whom received 2 doses and were evaluable for efficacy (per-protocol set, Ad26.COV2.S n=7484; placebo n=7008). Baseline demographics and characteristics were balanced. Vaccine efficacy was 75.2% (adjusted 95% CI, 54.6-87.3) against moderate to severe–critical Covid-19 and was similar against symptomatic infection (75.6% [55.5-99.9]). Efficacy was consistent across participants with and without comorbidities, and reached 93.7% (58.5-99.9) in the US. Vaccine efficacy against severe–critical Covid-19 was 100% (32.6-100.0; 0 vs 8 cases). The booster vaccine induced robust humoral responses and exhibited an acceptable safety profile. Conclusions A homologous Ad26.COV2.S booster administered 2 months after primary single-dose vaccination in adults led to high vaccine efficacy, including against any symptomatic infection and SARS-CoV-2 variants prevalent during the study. (Funding: Janssen Research and Development and others; ENSEMBLE2 [ClinicalTrials.gov][1] number, [NCT04614948][2].) ### Competing Interest Statement KH, AV, JS, MLG, JV, TK, GS, HS, JVH, MD, and FS are employees of Johnson & Johnson and hold Johnson & Johnson stock/stock options. CT, DL, and IVD are employees of Johnson & Johnson. JRG is an employee of Johnson & Johnson and holds Johnson & Johnson stock/stock options; he is a former employee of GSK, holds GSK stock/stock options, and has received funding grants from GSK Vaccines. CS has received funding grants for research from Janssen-Cilag, AbbVie, Apeiron, B.Braun, Cepheid, Eli Lilly, GSK, Corat Therapeutics, Gilead, MSD, Roche, and ViiV Healthcare; received consulting fees from AbbVie, Cepheid, Formycon, Gilead, GSK, Molecular partners, MSD, Swedish Orphan Biovitrium, Roche, and ViiV Healthcare; received honoraria from AbbVie, Cepheid, Formycon, Gilead, GSK, Gilead, Molecular partners, MSD, Swedish Orphan Biovitrium, Roche, and ViiV Healthcare; received travel support from AbbVie, Cepheid, Formycon, Gilead, GSK, Gilead, Molecular partners, MSD, Swedish Orphan Biovitrium, Roche, and ViiV Healthcare. SF has received research grants to his institution from Janssen/Johnson & Johnson, Pfizer, Sanofi, GSK, Merck, AstraZeneca, and Valneva (no personal fees); consulting fees from Janssen/Johnson & Johnson and GSK CureVac; fees to his institution for participation on a data safety monitoring board or advisory board from AstraZeneca, Medimmune, Sanofi, Pfizer, Seqirus, Sandoz, Merck, and Janssen/Johnson & Johnson; and was chair of two UK NICE sessions (expenses paid per NICE financial regulations). ### Clinical Trial NCT04614948 ### Funding Statement This work was supported by Janssen Vaccines & Prevention B.V. in collaboration with the Biomedical Advanced Research and Development Authority, the Department of Defense, the National Institutes of Health, and the COVID-19 Prevention Network. This project has been funded in whole or in part with federal funds from the Biomedical Advanced Research and Development Authority, part of the Office of the Assistant Secretary for Preparedness and Response at the U.S. Department of Health and Human Services (HHS), under Other Transaction Agreement HHSO100201700018C and from the National Institute of Allergy and Infectious Diseases (NIAID), NIH. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: All relevant ethical guidelines have been followed, all necessary institutional review board (IRB) and/or ethics committee approvals have been obtained, all necessary patient/participant consent has been obtained, and the appropriate institutional forms archived. The COV3009 (ENSEMBLE2) study was reviewed and approved by local ethics committees and IRBs (Algemeen Ziekenhuis Sint-Jan, Brugge, Belgium; Comissao Nacional de Etica em Pesquisa, Brasilia, Brazil; Instituto Nacional de Vigilancia de Medicamentos y Alimentos (Colombia), Bogota, Colombia; Comite de Protection des Personnes Ile de France III, Paris, France; Ethik-Kommission der Fakultaet f. Medizin der Technischen Universitaet Muenchen, Muenchen, Germany; Single Joint Research Ethics Board, Manila City, Philippines; Pharma Ethics, Pretoria, South Africa; Hospital Universitario La Paz, Madrid, Spain; UK NHS Research Ethics Service, Health Research Authority, London, United Kingdom; Copernicus Group IRB, Cary, North Carolina, United States. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes The data sharing policy of Janssen Pharmaceutical Companies of Johnson & Johnson is available at <https://www.janssen.com/clinical-trials/transparency>. As noted on this site, requests for access to the study data can be submitted through Yale Open Data Access (YODA) Project site at <http://yoda.yale.edu>. <http://yoda.yale.edu> [1]: http://ClinicalTrials.gov [2]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT04614948&atom=%2Fmedrxiv%2Fearly%2F2022%2F01%2F31%2F2022.01.28.22270043.atom

An inactivated poliovirus vaccine candidate using Sabin strains (sIPV) grown on the PER.C6® cell line was assessed in infants after demonstrated immunogenicity and safety in adults. The study recruited 300 infants who were randomized (1:1:1:1) to receive one of 3 dose levels of sIPV or a conventional IPV based on Salk strains (cIPV). Poliovirus-neutralizing antibodies were measured before the first dose and 28 days after the third dose. Reactogenicity was assessed for 7 days and unsolicited adverse events (AEs) for 28 days after each vaccination. Serious AEs (SAEs) were recorded throughout the study. Solicited AEs were mostly mild to moderate. None of the SAEs reported in the study were judged vaccine related, including one fatal SAE due to aspiration of vomitus that occurred 26 days after the third dose of low-dose sIPV. After 3 sIPV vaccinations and across all dose levels, seroconversion (SC) rates were at least 92% against Sabin poliovirus types and at least 80% against Salk types, with a dose-response in neutralizing antibody geometric mean titers (GMTs) observed across the 3 sIPV groups. Compared to cIPV, the 3 sIPV groups displayed similar or higher SC rates and GMTs against the 3 Sabin types but showed a lower response against Salk types 1 and 2; this was most visible for Salk type 1. While the PER.C6® cell line-based sIPV showed an acceptable safety profile and immunogenicity in infants, lower seroprotection against type 1 warrants optimization of dose level and additional clinical evaluation.

BACKGROUND The Ad26.COV2.S vaccine was highly effective against severe-critical coronavirus disease 2019 (Covid-19), hospitalization, and death in the primary phase 3 efficacy analysis. METHODS We conducted the final analysis in the double-blind phase of our multinational, randomized, placebo-controlled trial, in which adults were assigned in a 1:1 ratio to receive single-dose Ad26.COV2.S (5x10(10) viral particles) or placebo. The primary end points were vaccine efficacy against moderate to severe-critical Covid-19 with onset at least 14 days after administration and at least 28 days after administration in the per-protocol population. Safety and key secondary and exploratory end points were also assessed. RESULTS Median follow-up in this analysis was 4 months; 8940 participants had at least 6 months of follow-up. In the per-protocol population (39,185 participants), vaccine efficacy against moderate to severe-critical Covid-19 at least 14 days after administration was 56.3% (95% confidence interval [CI], 51.3 to 60.8; 484 cases in the vaccine group vs. 1067 in the placebo group); at least 28 days after administration, vaccine efficacy was 52.9% (95% CI, 47.1 to 58.1; 433 cases in the vaccine group vs. 883 in the placebo group). Efficacy in the United States, primarily against the reference strain (B.1.D614G) and the B.1.1.7 (alpha) variant, was 69.7% (95% CI, 60.7 to 76.9); efficacy was reduced elsewhere against the P.1 (gamma), C.37 (lambda), and B.1.621 (mu) variants. Efficacy was 74.6% (95% CI, 64.7 to 82.1) against severe-critical Covid-19 (with only 4 severe-critical cases caused by the B.1.617.2 [delta] variant), 75.6% (95% CI, 54.3 to 88.0) against Covid-19 leading to medical intervention (including hospitalization), and 82.8% (95% CI, 40.5 to 96.8) against Covid-19-related death, with protection lasting 6 months or longer. Efficacy against any severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was 41.7% (95% CI, 36.3 to 46.7). Ad26.COV2.S was associated with mainly mild-to-moderate adverse events, and no new safety concerns were identified. CONCLUSIONS A single dose of Ad26.COV2.S provided 52.9% protection against moderate to severe-critical Covid-19. Protection varied according to variant; higher protection was observed against severe Covid-19, medical intervention, and death than against other end points and lasted for 6 months or longer.

Abstract Background In a Phase 3 trial, the Janssen COVID-19 vaccine, Ad26.COV2.S, showed robust efficacy against severe–critical COVID-19 in countries where different SARS-CoV-2 variants were circulating. We evaluated Ad26.COV2.S-elicited antibody neutralizing activity against variants of concern (VOC) B.1.1.7 (Alpha), B.1.351 (Beta), and B.1.617.2 (Delta) in sera from participants in clinical trials following a single dose of Ad26.COV2.S. Methods Neutralizing activities of Ad26.COV2.S (given at a dose level of 5 x 1010 viral particles [vp]) against VOC were assessed by wild-type virus neutralizing (wtVNA) and pseudovirion neutralization (psVNA) assays in sera from participants in Phase 1/2a and Phase 3 clinical trials, respectively. Geometric mean titers (GMTs) were determined at Days 29 and 71 after vaccination. Results In serum samples from Phase 1/2a participants (n = 6), at Day 29 after 1 dose of Ad26.COV2.S, wtVNA titers against VOC were lower than for the original strain (GMT = 573), with GMT = 65, 14, and 15 for Alpha, Beta, and Delta, respectively, representing 8.8-, 40.9-, and 37.7-fold decreases. By Day 71 after vaccination (n = 14), fold differences between the original strain (GMT = 375) and VOC (GMT = 113, 27, and 28) were smaller (3.3-, 13.9-, and 13.4-fold) than at Day 29, suggestive of B-cell maturation (Figure 1). Day 71 titers against the Delta variant were maintained for at least 8 months following a single dose of Ad26.COV2.S (5 x 1010 vp). In serum samples from Phase 3 participants (n = 8), psVNA titers against VOC were lower than the original strain at Day 71 after vaccination, with the lowest titers observed for the Beta variant (3.6-fold decrease vs original strain). Smaller reductions in Nab titers for VOC were observed in the psVNA assay compared to wtVNA. Figure 1. Neutralization of B.1.1.7 (Alpha), B.1.351 (Beta), and B.1.617.2 (Delta) lineages in serum samples from participants who received Ad26.COV2.S. n = 6 samples at Day 29 and n = 14 (n = 14 for Alpha and Beta; n = 6 for Delta, comprising the same 6 participants at Day 29) samples at Day 71 after vaccination with a single dose of Ad26.COV2.S (5 x 10^10 vp dose level) were analyzed in wild-type virus neutralization assays against the SARS-CoV-2 Victoria strain (D614, black dots), the B.1.1.7 (Alpha; green dots) the B.1.351 (Beta; blue dots), and the B.1.617.2 (Delta; purple dots) lineages. Dots represent the IC50 (inhibitory concentration) titers per participant. Geometric mean titers (GMTs) and fold decrease in neutralizing activity between the original Victoria strain and each lineage are shown. Conclusion Ad26.COV2.S-elicited serum neutralizing activity against VOC showed an overall decrease in titers relative to the original strain that was largest for the Beta variant, even though vaccine efficacy against severe–critical COVID-19 was maintained in countries where these variants were circulating versus in countries where they were not circulating. Over time, titers against variants increased, suggesting B-cell affinity maturation leading to increasing coverage of VOC. Disclosures Mathieu Le Gars, n/a, Johnson & Johnson (Employee, Shareholder) Jerald Sadoff, MD, Johnson & Johnson (Employee, Shareholder) Mandy Jongeneelen, n/a, Johnson & Johnson (Employee, Shareholder) Dirk Heerwegh, n/a, Janssen Research and Development (Employee) Georgi Shukarev, MD, Janssen (Employee) Carla Truyers, n/a, Janssen Research and Development (Employee) Anne Marit de Groot, n/a, Johnson & Johnson (Employee) Gert Scheper, n/a, Johnson & Johnson (Employee, Shareholder) Jenny Hendriks, n/a, Johnson & Johnson (Employee, Shareholder) Boerries Brandenburg, n/a, Johnson & Johnson (Employee, Shareholder) Frank Struyf, n/a, Johnson & Johnson (Employee, Shareholder) Johan Van Hoof, n/a, Johnson & Johnson (Employee, Shareholder) Macaya Douoguih, MD, MPH, Janssen (Employee) Hanneke Schuitemaker, PhD, Johnson & Johnson (Employee, Shareholder)

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 (5×1010 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 ClinicalTrials.gov number, NCT04505722.).

Introduction: We assessed immunogenicity and safety of Ad26.COV2.S, a vector vaccine encoding the SARS-CoV-2 spike protein, at different dose levels and after a second dose in a randomized, placebo-controlled phase 2a study (NCT04535453). Methods: Healthy adults aged 18-55 and ≥65 y (n=602) were randomized to 1 of 10 groups to receive 1 or 2 doses of Ad26.COV2.S at 4 dose levels: 5×1010 vp (Groups 1, 5, 7, 9), 2.5×1010 vp (Group 2), 1.25×1010 vp (Group 3), 1×1011 vp (Group 4), or placebo (Groups 6, 8, 10). Dose 2 was given at day 57 (Groups 1-6) or day 85 (Groups 9, 10) with Groups 4-5 receiving placebo. Due to a study pause, Groups 7-8 received dose 2 later than scheduled. Humoral responses were measured at days15 and 29 post-dose 1 and 2 by wtVNA. Results: After dose 1, neutralizing antibodies were induced at different dose levels, including 1.25×1010 vp. Across dose levels, neutralizing titers were higher with younger age at day 15 (wtVNA geometric mean titer [GMT] range, 99-242 vs 61-125 for ages 18-55 vs ≥65 y) and day 29 (160-311 vs 113-187). After dose 2, titers were higher than after dose 1. Dose 2 induced a stronger antibody response when given at day 85 (Group 9, GMT=694) vs day 57 (Groups 1-3, GMT=420, 496, and 348). A similar trend was observed for binding antibody responses. Priming and boosting with 2.5×1010 vp appears to perform as well as 5×1010 vp. As reported previously, Ad26.COV2.S was well-tolerated. Conclusions: Doses as low as 1.25×1010 vp Ad26.COV2.S induced neutralizing and binding antibodies after 1 dose. Independent of dose level, boosting with a second dose increased antibody responses, which were further enhanced by an extended dosing interval.

AbstractBackgroundWe evaluated the durability of SARS-CoV-2 antibody levels elicited by the single dose Janssen COVID-19 vaccine, Ad26.COV2.S, and the impact on antibody responses of boosting with Ad26.COV2.S after 6 months in clinical trial participants.MethodsSpike-binding antibody and SARS-CoV-2 neutralizing antibody levels elicited by a single-dose Ad26.COV2.S (5×1010 viral particles [vp]) primary regimen and booster doses (5×1010 vp and 1.25×1010 vp) were assessed by ELISA and wild-type VNA in sera from participants in a Phase 1/2a clinical trial (Cohort 1a, 18–55 years old, N=25; Cohort 2a, 18–55 years old boosted at 6 months, N=17; Cohort 3, ≥65 years old, N=22) and a Phase 2 clinical trial (18–55 and ≥65-year old participants boosted at 6 months, total N=73). Neutralizing antibody levels were determined approximately 8 months after the primary vaccination in participants aged 18–55 years and approximately 9 months in participants aged ≥65 years. Binding antibody levels were evaluated 6 months after primary vaccination and 7- and 28-days after booster doses in both age groups.ResultsA single dose of Ad26.COV2.S elicited neutralizing antibodies that remained largely stable for approximately 8–9 months and binding antibodies that remained stable for at least 6 months irrespective of age group. A 5×1010 vp booster dose at 6 months post prime vaccination in 18–55-year-old adults elicited a steep and robust 9-fold increase at Day 7 post boost compared to Day 29 levels following the initial immunization. A lower booster dose of 1.25×1010 vp at 6 months in adults 18–55 and ≥65 years of age also elicited a rapid and high increase of 6–7.7 fold at Day 28 post boost compared to Day 29 levels following the initial immunization, with similar magnitude of post-boost responses in both age groups.ConclusionsA single dose of Ad26.COV2.S, which demonstrated protection in a Phase 3 efficacy trial, elicited durable neutralizing and binding antibodies for at least 8 and 6 months, respectively, in adults >18 years of age at levels similar to Day 29 responses. A 5×1010 vp or 1.25×1010 vp booster dose at 6 months elicited rapid and robust increases in spike binding antibody levels. The anamnestic responses after booster immunization imply robust immune memory elicited by single-dose Ad26.COV2.S.

Introduction: We assessed humoral responses against SARS-CoV-2 and variants of concern (VOC) and cellular immunogenicity of Ad26.COV2.S, a vector vaccine encoding the stabilized SARS-CoV-2 spike protein, in a randomized, placebo-controlled phase 1/2a trial (NCT04436276). Methods: Participants (cohort 1a [C1a], 18–≤55 y, n=300; cohort 3 [C3], ≥65 y, n=322) received 1 or 2 doses (56–85-day interval) of Ad26.COV2.S (5x1010 vp or 1x1011 vp). Spike-specific humoral (VNA, ELISA) and cellular (cytokine staining) responses were assessed at several timepoints post dose 1 (PD1) and 2 (PD2); C1a was tested against VOC. Results: In C1a and C3, neutralizing and non-neutralizing antibody functions were elicited after the 1st vaccine dose, including against VOC beta (B.1.351) and alpha (B.1.1.7) in C1a, albeit lower than for the original strain (41- and 8.9-fold, respectively). By day 71 PD1, neutralizing titers against VOC increased ~2-fold vs day 29 PD1 and were 14- and 3-fold lower for beta and alpha vs the original strain. A second dose at day 56 increased antibody responses in both cohorts; 14 days PD2, neutralizing activities increased ~3–4-fold vs day 71 PD1 for all strains. Ad26.COV2.S also elicited a high proportion of spike-specific polyfunctional and memory CD4 and CD8 T-cells in both cohorts that were maintained until at least 71 days PD1 and 2 weeks PD2. C1a and C3 8-month humoral/cellular durability are being evaluated. Conclusions: In adults aged ≥18 y, neutralizing antibody responses against the original strain and VOC are induced by a single dose of Ad26.COV2.S and are enhanced by a second dose. Polyfunctional/memory T-cell responses were also induced.

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 5x10(10) viral particles (low dose) or 1x10(11) 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], 224 to 354), regardless of vaccine dose or age group, and reached 100% 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.

ABSTRACTBACKGROUNDThe ongoing coronavirus disease (COVID)-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) might be controlled by an efficacious vaccine. Multiple vaccines are in development, but no efficacious vaccine is currently available.METHODSWe designed a multi-center phase 1/2a randomized, double-blinded, placebo-controlled clinical study to assesses the safety, reactogenicity and immunogenicity of Ad26.COV2.S, a non-replicating adenovirus 26 based vector expressing the stabilized pre-fusion spike (S) protein of SARS-CoV-2. Ad26.COV2.S was administered at a dose level of 5×1010 or 1×1011 viral particles (vp) per vaccination, either as a single dose or as a two-dose schedule spaced by 56 days in healthy adults (18-55 years old; cohort 1a & 1b; n= 402 and healthy elderly ≥65 years old; cohort 3; n=394). Vaccine elicited S specific antibody levels were measured by ELISA and neutralizing titers were measured in a wild-type virus neutralization assay (wtVNA). CD4+ T-helper (Th)1 and Th2, and CD8+ immune responses were assessed by intracellular cytokine staining (ICS).RESULTSWe here report interim analyses after the first dose of blinded safety data from cohorts 1a, 1b and 3 and group unblinded immunogenicity data from cohort 1a and 3. In cohorts 1 and 3 solicited local adverse events were observed in 58% and 27% of participants, respectively. Solicited systemic adverse events were reported in 64% and 36% of participants, respectively. Fevers occurred in both cohorts 1 and 3 in 19% (5% grade 3) and 4% (0% grade 3), respectively, were mostly mild or moderate, and resolved within 1 to 2 days after vaccination. The most frequent local adverse event (AE) was injection site pain and the most frequent solicited AEs were fatigue, headache and myalgia. After only a single dose, seroconversion rate in wtVNA (50% inhibitory concentration - IC50) at day 29 after immunization in cohort 1a already reached 92% with GMTs of 214 (95% CI: 177; 259) and 92% with GMTs of 243 (95% CI: 200; 295) for the 5×1010 and 1×1011vp dose levels, respectively. A similar immunogenicity profile was observed in the first 15 participants in cohort 3, where 100% seroconversion (6/6) (GMTs of 196 [95%CI: 69; 560]) and 83% seroconversion (5/6) (GMTs of 127 [95% CI: <58; 327]) were observed for the 5×1010 or 1×1011 vp dose level, respectively. Seroconversion for S antibodies as measured by ELISA (ELISA Units/mL) was observed in 99% of cohort 1a participants (GMTs of 528 [95% CI: 442; 630) and 695 (95% CI: 596; 810]), for the 5×1010 or 1×1011 vp dose level, respectively, and in 100% (6/6 for both dose levels) of cohort 3 with GMTs of 507 (95% CI: 181; 1418) and 248 (95% CI: 122; 506), respectively. On day 14 post immunization, Th1 cytokine producing S-specific CD4+ T cell responses were measured in 80% and 83% of a subset of participants in cohort 1a and 3, respectively, with no or very low Th2 responses, indicative of a Th1-skewed phenotype in both cohorts. CD8+ T cell responses were also robust in both cohort 1a and 3, for both dose levels.CONCLUSIONSThe safety profile and immunogenicity after only a single dose are supportive for further clinical development of Ad26.COV2.S at a dose level of 5×1010 vp, as a potentially protective vaccine against COVID-19.Trial registration numberNCT04436276

Given that oropharyngeal squamous cell carcinoma (OPSCC) have now surpassed cervical cancer as the most common human papillomavirus (HPV)‐driven cancer, there is an interest in developing non‐invasive predictive biomarkers to early detect HPV‐driven OPSCC. In total, 665 cancer‐free individuals were recruited from Queensland, Australia. Oral HPV16 DNA positivity in those individuals was determined by our in‐house developed sensitive PCR method. Individuals with (n = 9) or without (n = 12) oral HPV16 infections at baseline were followed for a median duration of 24 mo. Individuals with persistent oral HPV16 infection (≥ 30 mo) were invited for clinical examination of their oral cavity and oropharynx by an otolaryngologist. Oral HPV16 DNA was detected in 12 out of 650 cancer‐free individuals (1.8%; 95% confidence interval [CI]: 1.0‐3.2). Of the 3 individuals with persistent oral HPV16 infection, the first individual showed no clinical evidence of pathology. The second individual was diagnosed with a 2 mm invasive squamous cell carcinoma (T1N0M0) positive for both p16INK4a expression and HPV16 DNA. The third individual was found to have a mildly dysplastic lesion in the tonsillar region that was negative for p16INK4a expression and HPV16 DNA and she continues to have HPV16 DNA in her saliva. Taken together, our data support the value of using an oral HPV16 DNA assay as a potential screening tool for the detection of microscopic HPV‐driven OPSCC. Larger multicenter studies across various geographic regions recruiting populations at a higher risk of developing HPV‐driven OPSCC are warranted to extend and confirm the results of the current investigation.

The role of human papillomavirus type 16 (HPV16) in oral potentially malignant disorders (OPMD) and oral cavity carcinoma (OC) is still under debate. We investigated HPV16 prevalence in unstimulated saliva, oral rinse samples, oral swabs and tumour biopsies collected from OPMD (n = 83) and OC (n = 106) patients. HPV16 genotype, viral load, physical status (episomal vs. integrated) and tumour p16INK4a expression were determined. Oral HPV16 prevalence was higher in OC than in OPMD, but this difference was not statistically significant (7.5% (8/106) versus 3.6% (3/83), odds ratio (OR): 2.18, 95% confidence interval (CI): 0.56, 8.48, p = 0.26). There was a significant association (p < 0.05) between oral HPV16 infection and heavy tobacco consumption. Real-time PCR results indicated that no integration events occurred in either OPMD or OC cases based on the HPV16 E2/E6 ratio. HPV16 positive OPMD and OC patients had similar HPV16 E2 and E6 viral loads. The inter-rater agreement between tumour p16INK4a expression and oral HPV16 infection was considered as fair (k = 0.361) for OC. Our data suggest that the involvement of HPV16 in oral carcinogenesis is limited.

The incidence of human papillomavirus (HPV)-positive oropharyngeal cancer (OPC) is rising in high-income countries, including Australia. Increasing evidence suggests that accurate HPV testing is pivotal for clinical decision making and treatment planning in these patients. Recently, the eighth edition of the American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) tumor–node–metastasis (TNM) staging system for OPC (based on the p16INK4a (p16) status) was proposed and has been implemented. However, the applicability of this new staging system is still far from clear. In our study, n = 127 OPC patients from Queensland, Australia were recruited, and the tumor p16 expression in these patients was examined using immunohistochemical (IHC) analysis. HPV-16 genotyping, viral load, and physical status (episomal versus integrated) in the saliva samples of OPC patients were determined using the qPCR method. A good inter-rater agreement (k = 0.612) was found between tumor p16 expression and oral HPV-16 infection in OPC. Importantly, according to the eighth edition staging system, HPV-16 DNA viral load (>10 copies/50 ng) was significantly associated with the advanced stages of OPC. In concordance with previous studies, a mixed HPV-16 form (partially or fully integrated) was predominately found in OPC patients. Taken together, our data support HPV-16 detection in saliva as a screening biomarker to identify people within the community who are at risk of developing OPC.