A phase 2b/3b MenACWY-TT study of long-term antibody persistence after primary vaccination and immunogenicity and safety of a booster dose in individuals aged 11 through 55 years

Antibody persistence and revaccination recommendations of MenACWY-TT: a review of clinical studies assessing antibody persistence up to 10 years after vaccination

INTRODUCTION

Invasive meningococcal disease (IMD) is potentially fatal and associated with severe sequelae among survivors. It is preventable by several vaccines, including meningococcal vaccines targeting the most common disease-causing serogroups (A, B, C, W, Y). The meningococcal ACWY tetanus toxoid conjugate vaccine (MenACWY-TT [Nimenrix]) is indicated from 6 weeks of age in the European Union and >50 additional countries.

AREAS COVERED

Using PubMed, Google Scholar, ClinicalTrials.gov and ad hoc searches for publications to June 2023, we review evidence of antibody persistence for up to 10 years after primary vaccination and up to 6 years after MenACWY-TT revaccination. We also review global MenACWY revaccination recommendations and real-world impact of vaccination policies, focusing on how these data can be considered alongside antibody persistence data to inform future IMD prevention strategies.

EXPERT OPINION

Based on clear evidence that immunogenicity data (demonstrated antibody titers above established correlates of protection) are correlated with real-world effectiveness, long-term persistence of antibodies after MenACWY-TT vaccination suggests continuing protection against IMD. Optimal timing of primary and subsequent vaccinations is critical to maximize direct and indirect protection. Recommending bodies should carefully consider factors such as age at vaccination and long-term immune responses associated with the specific vaccine being used.

Assessing the Role of Infant and Toddler MenACWY Immunisation in the UK: Does the Adolescent MenACWY Programme Provide Sufficient Protection?

A combined Haemophilus influenzae type b (Hib)/meningococcal serogroup C (MenC) vaccine will soon be unavailable in the UK immunisation schedule due to discontinuation by the manufacturer. An interim statement by the Joint Committee on Vaccination and Immunisation (JCVI) advises stopping MenC immunisation at 12 months of age when this occurs. We undertook an analysis of the public health impact of various potential meningococcal vaccination strategies in the UK in the absence of the Hib/MenC vaccine. A static population-cohort model was developed evaluating the burden of IMD (using 2005-2015 epidemiological data) and related health outcomes (e.g., cases, cases with long-term sequelae, deaths), which allows for the comparison of any two meningococcal immunisation strategies. We compared potential strategies that included different combinations of infant and/or toddler MenACWY immunisations with the anticipated future situation in which a 12-month MenC vaccine is not used, but the MenACWY vaccine is routinely given in adolescents. The most effective strategy is combining MenACWY immunisation at 2, 4, and 12 months of age with the incumbent adolescent MenACWY immunisation programme, resulting in the prevention of an additional 269 IMD cases and 13 fatalities over the modelling period; of these cases, 87 would be associated with long-term sequelae. Among the different vaccination strategies, it was observed that those with multiple doses and earlier doses provided the greatest protection. Our study provides evidence suggesting that the removal of the MenC toddler immunisation from the UK schedule would potentially increase the risk of unnecessary IMD cases and have a detrimental public health impact if not replaced by an alternate infant and/or toddler programme. This analysis supports that infant and toddler MenACWY immunisation can provide maximal protection while complementing both infant/toddler MenB and adolescent MenACWY immunisation programmes in the UK.

A phase 3, randomized, controlled, open-label study to evaluate the persistence up to 5 years of 1 or 2 doses of meningococcal conjugate vaccine MenACWY-TT given with or without 13-valent pneumococcal conjugate vaccine in 12-14-month-old children

BACKGROUND

Immunogenicity and safety up to 5 years after administration of 1 or 2 doses of quadrivalent meningococcal serogroup A, C, W, and Y tetanus toxoid conjugate vaccine (MenACWY-TT) given alone or with 13-valent pneumococcal conjugate vaccine (PCV13) in children was investigated.

METHODS

This phase 3 study randomized healthy 12-24-month-olds to MenACWY-TT at Month 0 (ACWY1d), MenACWY-TT at Months 0 and 2 (ACWY2d), MenACWY-TT and PCV13 at Month 0 (Co-Ad), or PCV13 at Month 0 and MenACWY-TT at Month 2 (PCV13/ACWY). Immune responses 1, 3, and 5 years after primary vaccination were evaluated with serum bactericidal activity using rabbit complement (rSBA) titers ≥ 1:8 and geometric mean titers (GMTs). Evaluation of serious adverse events up to 5 years after primary vaccination are reported.

RESULTS

Of the 802 children randomized in the study, 619 completed the study through Year 5. Immune responses after vaccination declined over time but were higher 5 years after vaccination compared with levels before vaccination. At Year 5, the percentages of children with rSBA titers ≥ 1:8 across all serogroups were 20.5 %-58.6 %, 28.4 %-65.8 %, 23.9 %-52.8 %, and 19.4 %-55.8 % in the ACWY1d, ACWY2d, Co-Ad, and PCV13/ACWY groups, respectively. Comparable antibody persistence at Year 5 was observed for participants receiving 1 or 2 doses of MenACWY-TT, although GMTs were elevated in those who received 2 versus 1 dose. The percentage of children with protective antibody titers at Year 5 was similar in participants who received PCV13 and MenACWY-TT compared with that observed for participants who only received 1 or 2 MenACWY-TT doses. No new safety concerns were identified during the study period.

CONCLUSION

Antibody responses persisted in the majority of children up to 5 years after primary vaccination with MenACWY-TT administered in a 1- or 2-dose regimen with or without PCV13, with no new safety concerns identified.

CLINICALTRIALS

gov Identifier NCT01939158; EudraCT number 2013-001083-28.

Clinical trial and postmarketing safety experience with MenACWY-TT, a meningococcal group A, C, W, and Y tetanus conjugate vaccine

BACKGROUND

The meningococcal serogroups A, C, W, and Y tetanus toxoid conjugate vaccine (MenACWY-TT; Nimenrix®; Pfizer Ltd, Sandwich, Kent, UK) is licensed in more than 80 countries worldwide for the prevention of meningococcal disease caused by serogroups A, C, W, and Y in individuals throughout their lifespans. This report summarizes safety data from the MenACWY-TT clinical development program and postmarketing experience.

METHODS

Within the clinical study program, reactogenicity data were based on 3 primary studies, including a large pooled analysis across multiple age groups, and long-term safety data were derived from 3 studies evaluating long-term antibody persistence. Postmarketing safety data through April 19, 2021, were collected and analyzed in connection with the MenACWY-TT Periodic Safety Update Report.

RESULTS

Approximately 32 million doses of MenACWY-TT have been administered worldwide, with more than 21,530 additional individuals receiving MenACWY-TT as part of clinical trials. The safety profile of MenACWY-TT was consistent between the clinical study program and the postmarketing experience, as well as with other licensed meningococcal vaccines. The most commonly observed adverse events (AEs) were pyrexia/fever, headache, injection site pain/reactions, nausea/vomiting, and fatigue; serious AEs were rare relative to the number of doses administered. Several cases of serogroup replacement/lack of efficacy were observed in the 1-year postmarketing period but did not appear to be related to MenACWY-TT use.

CONCLUSION

Extensive data derived from clinical trials and postmarketing experience indicate a consistently favorable safety profile for MenACWY-TT across a wide range of age groups.

Invasive meningococcal disease in Chile seven years after ACWY conjugate vaccine introduction

BACKGROUND

A serogroup W (MenW) outbreak in Chile prompted a meningococcal vaccination campaign using tetravalent meningococcal-conjugate vaccines (MCV-ACWY) in children since 2012, followed by its introduction into the National Immunization Program (NIP) in toddlers from 2014. Direct protection was observed, but no indirect effects in other age-groups were evidenced. The aim of this study was to describe invasive meningococcal disease (IMD) cases in Chile between 2009 and 2019, and its trend after the introduction of MCV-ACWYs.

METHODS

IMD cases, cumulative incidence per 100,000 inhabitants, CFR, and vaccination uptake were described. Data were obtained from the Public Health Institute and NIP.

RESULTS

Overall-IMD cases increased in 2009-2014 period, followed by a decline in 2015-2019, focused in infants, children <5 years and people ≥60 years. Serogroup B (MenB) and MenW alternate its predominance. Median overall incidence was 0.6/100,000, increasing from 0.6/100,000 in 2009 to 0.8/100,000 in 2014, later decreasing to 0.4/100,000 in 2019. Median incidences for MenB, serogroup C (MenC) and Y (MenY) were 0.25/100,000, <0.01/100,000 and <0.01/100,000, respectively. Median MenW incidence was 0.53/100,000, increasing from 0.01/100,000 in 2009 to 0.56/100,000 in 2014, followed by a constant decline to 0.12 in 2019. Infants, children <5 years and adults ≥60 years were affected the most, with median incidences of 9.7, 0.9 and 0.93, decreasing to 1.3, 0.1 and 0.1/100,000 in 2019, respectively. Median overall-CFR was 19%, 7.5% for MenB and 24.5% for MenW. Median MCV-ACWY uptake was 93% CONCLUSION: Overall-IMD, MenW cases and incidence declined since 2015 after the MCV-ACWY introduction, while MenB, MenC and MenY have been stable. MenW incidence declined in all age groups, including non-immunized infants and people >60 years. Further analysis and a longer period of observation are needed to have a more robust conclusion about this epidemiological trend. By 2019, CFR remains high.

Potential public health impact of a Neisseria meningitidis A, B, C, W, and Y pentavalent vaccine in the United States

Objective: Globally, 5 serogroups (A, B, C, W, and Y) cause the majority of invasive meningococcal disease (IMD). Vaccines targeting these serogroups are currently part of the US adolescent immunization platform, which includes 1 + 1 dosing of a MenACWY vaccine routinely at ages 11 and 16 years and 2 doses of a MenB vaccine at age 16-23 years under shared clinical decision-making between the patient and healthcare provider. In 2018, MenACWY vaccination coverage was 86.6% for ≥1 dose and 50.8% for ≥2 doses, whereas MenB vaccination coverage was 17.2% for ≥1 dose and <50% for completion of the multidose series. A pentavalent MenABCWY vaccine could simplify immunization schedules and improve vaccination coverage. We estimated the public health impact of a pentavalent MenABCWY vaccine using a model that considers meningococcal carriage and vaccination coverage.Methods: A population-based dynamic model estimated the 10-year reduction in IMD from implementing a MenABCWY vaccine within the existing US meningococcal immunization platform. Five vaccination schedules (4 new, 1 existing) were examined to estimate the impact of different recommendations on the overall reduction in the number of IMD cases. Sensitivity analyses were performed by varying vaccination coverage at age 16 years.Results: The existing schedule and coverage of MenACWY and MenB vaccines (total 4 doses) could potentially avert 165 IMD cases over 10 years versus no vaccination. Assuming similar MenABCWY and MenACWY vaccination coverage rates at age 16 years, replacing 1 or more MenACWY and/or MenB doses with MenABCWY could avert more cases, ranging from 189 to 256. The most beneficial MenABCWY vaccine schedule was 2 doses at age 11 years and 1 dose at age 16 years.Conclusions: Replacing one or more MenACWY/MenB vaccine doses with MenABCWY could reduce IMD caused by all 5 meningococcal serogroups among the US adolescent population, while also reducing the number of injections required.

Different Long-Term Duration of Seroprotection against Neisseria meningitidis in Adolescents and Middle-Aged Adults after a Single Meningococcal ACWY Conjugate Vaccination in The Netherlands

Neisseria meningitidis is often asymptomatically carried in the nasopharynx but may cause invasive meningococcal disease, leading to morbidity and mortality. Meningococcal conjugate vaccinations induce functional protective antibodies against capsular antigens, but seroprotection wanes over time. We measured functional antibody titers five years after administration of a single dose of the meningococcal ACWY-polysaccharide-specific tetanus toxoid-conjugated (MenACWY-TT) vaccine in adolescents and middle-aged adults in the Netherlands, using the serum bactericidal antibody with baby rabbit complement (rSBA) assay. Protection was defined as rSBA titer ≥8. The meningococcal ACWY-specific serum IgG concentrations were measured with a multiplex immunoassay. Duration of protection was estimated by a bi-exponential decay model. Sufficient protection for MenC, MenW, and MenY was achieved in 94–96% of the adolescents five years postvaccination, but, in middle-aged adults, only in 32% for MenC, 65% for MenW and 71% for MenY. Median duration of protection for MenCWY was 4, 14, and 21 years, respectively, in middle-aged adults, while, in adolescents, it was 32, 98, and 33 years. Our findings suggest that adolescents, primed in early childhood with MenC conjugate vaccination, remain sufficiently protected after a single dose of MenACWY-TT vaccine. Middle-aged adults without priming vaccination show fast waning of antibodies, particularly MenC, for which protection is lost after four years.