Stage I of this study (NCT04142242) demonstrated the safety and immunogenicity of a booster dose of a licensed quadrivalent meningococcal tetanus toxoid-conjugate vaccine (MenACYW-TT) and immune persistence 3 and 6-7 years after priming in older adults who received either quadrivalent meningococcal polysaccharide vaccine (MPSV4) or MenACYW-TT at >= 56 years of age. Stage II, reported here, assessed the antibody persistence after MenACYW-TT versus MPSV4 priming and the safety and immunogenicity of a booster dose of MenACYW-TT in older adults 5 years after primary vaccination with either MPSV4 or MenACYW-TT. A serum bactericidal assay (hSBA) was used to measure functional antibodies against each serogroup immediately before MenACYW-TT booster vaccination and on day (D) 30 post-booster. Safety was also assessed. Antibody persistence declined 5 years post-primary vaccination, with seroprotection (hSBA titer >= 1:8) rates trending higher in MenACYW-TT- versus MPSV4-primed participants. A robust immune response for all four serogroups was observed on D30 after the MenACYW-TT booster, with higher geometric mean titers and seroprotection rates in MenACYW-TT- versus MPSV4-primed participants. Safety outcomes were similar between the two groups. A single booster dose of MenACYW-TT was well tolerated and immunogenic in older adults, with a higher immune response observed in those primed with MenACYW-TT.

This 2-stage Phase III study (NCT04142242) of a recently licensed quadrivalent meningococcal tetanus toxoid-conjugate vaccine (MenACYW-TT) assessed the safety and immunogenicity of a booster dose in older adults (≥59 years) primed with either MenACYW-TT or a quadrivalent meningococcal polysaccharide vaccine (MPSV4). Immune persistence of MenACYW-TT and MPSV4 after primary vaccination was also evaluated. During Stage I, the participants administered MPSV4 (n = 165) or MenACYW-TT (n = 236) 3 years previously were randomized 9:2 to receive either a MenACYW-TT booster or to have blood drawn for persistence only. Participants primed with MPSV4 or MenACYW-TT 6–7 years previously had blood drawn for antibody persistence only. A serum bactericidal assay using human complement was used to measure functional antibodies against each serogroup at baseline and, for those receiving a booster, 30 days post-vaccination (D30). Proportions of participants with seroresponse (post-vaccination titers ≥1:16 when baseline titers <1:8 or ≥ 4-fold increase when baseline titers ≥1:8) were determined. Safety data were collected up to D30. Seroresponse rates for all serogroups at D30 ranged from 49.2% to 60.8% in the MPSV4-primed group, and 79.3–93.1% in the MenACYW-TT-primed group. MenACYW-TT induced sufficient seroresponses in each primed group. Geometric mean titers (GMTs) for serogroups C, W, and Y remained or trended higher than pre-vaccination levels at both 3 and 6–7 years after primary vaccination, indicating immune persistence. Safety outcomes were comparable between groups. A MenACYW-TT booster was immunogenic and well tolerated in participants aged ≥59 years regardless of previous quadrivalent meningococcal vaccine received. The greatest immune responses occurred in those primed with MenACYW-TT.

Abstract Background MenACYW-TT (MenQuadfi®, Sanofi) is a quadrivalent (serogroups A, C, W, and Y) meningococcal tetanus toxoid conjugate vaccine. It is approved for use in persons aged ≥2 years in the US and persons aged ≥1 year in Europe and certain other countries; trials in infants as young as 6 weeks are ongoing. The second stage of a 2-stage study of MenACYW-TT, reported herein, evaluated immune persistence among older adults who received primary vaccination with either quadrivalent meningococcal polysaccharide vaccine (MSPV4) or MenACYW-TT five years earlier at age ≥ 56 years. The immunogenicity and safety of a MenACYW-TT booster dose given to this population were also evaluated. Methods This was a Phase 3, 2-stage, randomized, open-label, multi-center study (NCT04142242) of adults aged ≥59 years who participated in previous studies of MenACYW-TT vs MPSV4 (NCT01732627 and NCT02842866). The study was conducted in the US and Puerto Rico. Immune persistence and response were assessed with a serum bactericidal assay using human complement (hSBA). Safety data were collected for up to 30 days after booster vaccination. All analyses were descriptive. Results Of the initial study population (N=471), 70 adults participated in Stage II of the study. At 5 years post-primary vaccination, seroprotection (hSBA ≥ 1:8) rates (SPRs) and hSBA geometric mean titers (GMTs) declined in both MenACYW-TT- and MPSV4-primed subjects, with SPRs and hSBA GMTs for serogroups A, C, W, and Y trending higher in MenACYW-TT- vs MPSV4-primed subjects (Table 1). Thirty days after booster vaccination, hSBA GMTs and SPRs increased from pre-booster for all serogroups and were, along with seroresponse rates, higher in MenACYW-TT-primed subjects compared to MPSV4-primed subjects (Table 2). Rates of AEs following booster vaccination were similar regardless of priming vaccine. No safety concerns were identified. Conclusion Five years after primary vaccination, immune persistence tended to be greater for MenACYW-TT vs MPSV4. A MenACYW-TT booster was well tolerated and immunogenic in adults ≥ 61 years, when administered 5 years after primary vaccination with either MPSV4 or MenACYW-TT. Disclosures Corwin A. Robertson, MD, MPH, FACP, Sanofi: Sanofi employee|Sanofi: Sanofi's Employee|Sanofi: Stocks/Bonds Katherine Galarza, MD, Sanofi: Sanofi employee|Sanofi: Stocks/Bonds Alexandre Selmani, PhD, Sanofi: Sanofi employee|Sanofi: Stocks/Bonds Philipp Oster, MD, Sanofi: Sanofi employee

ImportanceCurrent data identifying COVID-19 risk factors lack standardized outcomes and insufficiently control for confounders.ObjectiveTo identify risk factors associated with COVID-19, severe COVID-19, and SARS-CoV-2 infection.Design, Setting, and ParticipantsThis secondary cross-protocol analysis included 4 multicenter, international, randomized, blinded, placebo-controlled, COVID-19 vaccine efficacy trials with harmonized protocols established by the COVID-19 Prevention Network. Individual-level data from participants randomized to receive placebo within each trial were combined and analyzed. Enrollment began July 2020 and the last data cutoff was in July 2021. Participants included adults in stable health, at risk for SARS-CoV-2, and assigned to the placebo group within each vaccine trial. Data were analyzed from April 2022 to February 2023.ExposuresComorbid conditions, demographic factors, and SARS-CoV-2 exposure risk at the time of enrollment.Main Outcomes and MeasuresCoprimary outcomes were COVID-19 and severe COVID-19. Multivariate Cox proportional regression models estimated adjusted hazard ratios (aHRs) and 95% CIs for baseline covariates, accounting for trial, region, and calendar time. Secondary outcomes included severe COVID-19 among people with COVID-19, subclinical SARS-CoV-2 infection, and SARS-CoV-2 infection.ResultsA total of 57 692 participants (median [range] age, 51 [18-95] years; 11 720 participants [20.3%] aged ≥65 years; 31 058 participants [53.8%] assigned male at birth) were included. The analysis population included 3270 American Indian or Alaska Native participants (5.7%), 7849 Black or African American participants (13.6%), 17 678 Hispanic or Latino participants (30.6%), and 40 745 White participants (70.6%). Annualized incidence was 13.9% (95% CI, 13.3%-14.4%) for COVID-19 and 2.0% (95% CI, 1.8%-2.2%) for severe COVID-19. Factors associated with increased rates of COVID-19 included workplace exposure (high vs low: aHR, 1.35 [95% CI, 1.16-1.58]; medium vs low: aHR, 1.41 [95% CI, 1.21-1.65]; P < .001) and living condition risk (very high vs low risk: aHR, 1.41 [95% CI, 1.21-1.66]; medium vs low risk: aHR, 1.19 [95% CI, 1.08-1.32]; P < .001). Factors associated with decreased rates of COVID-19 included previous SARS-CoV-2 infection (aHR, 0.13 [95% CI, 0.09-0.19]; P < .001), age 65 years or older (aHR vs age <65 years, 0.57 [95% CI, 0.50-0.64]; P < .001) and Black or African American race (aHR vs White race, 0.78 [95% CI, 0.67-0.91]; P = .002). Factors associated with increased rates of severe COVID-19 included race (American Indian or Alaska Native vs White: aHR, 2.61 [95% CI, 1.85-3.69]; multiracial vs White: aHR, 2.19 [95% CI, 1.50-3.20]; P < .001), diabetes (aHR, 1.54 [95% CI, 1.14-2.08]; P = .005) and at least 2 comorbidities (aHR vs none, 1.39 [95% CI, 1.09-1.76]; P = .008). In analyses restricted to participants who contracted COVID-19, increased severe COVID-19 rates were associated with age 65 years or older (aHR vs <65 years, 1.75 [95% CI, 1.32-2.31]; P < .001), race (American Indian or Alaska Native vs White: aHR, 1.98 [95% CI, 1.38-2.83]; Black or African American vs White: aHR, 1.49 [95% CI, 1.03-2.14]; multiracial: aHR, 1.81 [95% CI, 1.21-2.69]; overall P = .001), body mass index (aHR per 1-unit increase, 1.03 [95% CI, 1.01-1.04]; P = .001), and diabetes (aHR, 1.85 [95% CI, 1.37-2.49]; P < .001). Previous SARS-CoV-2 infection was associated with decreased severe COVID-19 rates (aHR, 0.04 [95% CI, 0.01-0.14]; P < .001).Conclusions and RelevanceIn this secondary cross-protocol analysis of 4 randomized clinical trials, exposure and demographic factors had the strongest associations with outcomes; results could inform mitigation strategies for SARS-CoV-2 and viruses with comparable epidemiological characteristics.

Abstract Background MenACYW-TT (MenQuadfi®, Sanofi) is a quadrivalent (serogroups A, C, W, and Y) meningococcal tetanus toxoid conjugate vaccine. It was recently approved for use in persons aged ≥ 2 years in the US and persons aged ≥ 1 year in Europe and certain other countries; trials in infants as young as 6 weeks are ongoing. This study evaluated seroresponse after a MenACYW-TT booster given to adults who received either quadrivalent meningococcal polysaccharide vaccine (MSPV4) or MenACYW-TT three years earlier at age ≥ 56 years. Immune persistence up to 7 years after primary vaccination was also evaluated. Methods This was a Phase 3 randomized, open-label study (NCT04142242) of adults aged ≥ 59 years who participated in previous studies of MenACYW-TT vs MPSV4 (NCT01732627 and NCT02842866). The study was conducted in the US and Puerto Rico. Immune response and persistence were assessed with a serum bactericidal assay using human complement (hSBA). Sufficiency of the vaccine seroresponse was considered demonstrated if the lower limit of the 1-sided 97.5% CI for the percentage of subjects with an hSBA vaccine seroresponse against serogroups A, C, W and Y was > 40%. Safety data were collected up to 30 days after booster vaccination. Results A total of 471 persons were enrolled. Sufficiency of a MenACYW-TT booster was demonstrated for MPSV4- and for MenACYW-TT-primed subjects. hSBA seroresponse rates were higher among MenACYW-TT- vs MPSV4-primed subjects (79.3%–93.1% vs 49.2%–60.8%, respectively). Three to 7 years after primary vaccination, hSBA geometric mean titers (GMTs) and seroprotection rates (SPRs) declined in both MenACYW-TT- and MPSV4-primed subjects, with hSBA GMTs and SPRs for serogroups C, W, and Y generally remaining higher for MenACYW-TT- vs MPSV4-primed subjects; those for serogroup A were similar regardless of priming vaccine. Rates of adverse events following a MenACYW-TT booster were similar between MenACYW-TT- and MPSV4-primed subjects. No safety concerns were identified. Conclusion A MenACYW-TT booster was well tolerated and immunogenic when administered to either MPSV4- or MenACYW-primed adults aged ≥ 59 years. Up to 7 years after primary vaccination, immune persistence for serogroups C, W, and Y tended to be greater for MenACYW-TT vs MPSV4. Disclosures Corwin A. Robertson, MD, MPH, FACP, Sanofi Pasteur (Employee, Other Financial or Material Support, Stockholder) Alexandre Selmani, PhD, Sanofi Pasteur (Employee) Katherine Galarza, MD, Sanofi Pasteur (Employee) Philipp Oster, MD, Sanofi Pasteur (Employee, Stockholder)