Early estimate of the effectiveness of quadrivalent meningococcal conjugate vaccine

Meningococcal ACWYX Conjugate Vaccine in 2-to-29-Year-Olds in Mali and Gambia

BACKGROUND

An effective, affordable, multivalent meningococcal conjugate vaccine is needed to prevent epidemic meningitis in the African meningitis belt. Data on the safety and immunogenicity of NmCV-5, a pentavalent vaccine targeting the A, C, W, Y, and X serogroups, have been limited.

METHODS

We conducted a phase 3, noninferiority trial involving healthy 2-to-29-year-olds in Mali and Gambia. Participants were randomly assigned in a 2:1 ratio to receive a single intramuscular dose of NmCV-5 or the quadrivalent vaccine MenACWY-D. Immunogenicity was assessed at day 28. The noninferiority of NmCV-5 to MenACWY-D was assessed on the basis of the difference in the percentage of participants with a seroresponse (defined as prespecified changes in titer; margin, lower limit of the 96% confidence interval [CI] above -10 percentage points) or geometric mean titer (GMT) ratios (margin, lower limit of the 98.98% CI >0.5). Serogroup X responses in the NmCV-5 group were compared with the lowest response among the MenACWY-D serogroups. Safety was also assessed.

RESULTS

A total of 1800 participants received NmCV-5 or MenACWY-D. In the NmCV-5 group, the percentage of participants with a seroresponse ranged from 70.5% (95% CI, 67.8 to 73.2) for serogroup A to 98.5% (95% CI, 97.6 to 99.2) for serogroup W; the percentage with a serogroup X response was 97.2% (95% CI, 96.0 to 98.1). The overall difference between the two vaccines in seroresponse for the four shared serogroups ranged from 1.2 percentage points (96% CI, -0.3 to 3.1) for serogroup W to 20.5 percentage points (96% CI, 15.4 to 25.6) for serogroup A. The overall GMT ratios for the four shared serogroups ranged from 1.7 (98.98% CI, 1.5 to 1.9) for serogroup A to 2.8 (98.98% CI, 2.3 to 3.5) for serogroup C. The serogroup X component of the NmCV-5 vaccine generated seroresponses and GMTs that met the prespecified noninferiority criteria. The incidence of systemic adverse events was similar in the two groups (11.1% in the NmCV-5 group and 9.2% in the MenACWY-D group).

CONCLUSIONS

For all four serotypes in common with the MenACWY-D vaccine, the NmCV-5 vaccine elicited immune responses that were noninferior to those elicited by the MenACWY-D vaccine. NmCV-5 also elicited immune responses to serogroup X. No safety concerns were evident. (Funded by the U.K. Foreign, Commonwealth, and Development Office and others; ClinicalTrials.gov number, NCT03964012.).

Immunogenicity and safety of MenACWY-TT, a quadrivalent meningococcal tetanus toxoid conjugate vaccine recently licensed in the United States for individuals ≥2 years of age

Vaccination offers the best way to prevent invasive meningococcal disease (IMD). As demonstrated in countries with national immunization programs (NIPs) against IMD, meningococcal conjugate vaccines have contributed to significant declines in incidence. Since some meningococcal vaccines are associated with modest immunogenicity in infants, possible immunological interference upon concomitant administration with some pediatric vaccines, and administration errors resulting from improper reconstitution, opportunities for improvement exist. A quadrivalent conjugate vaccine, MenQuadfi® (Meningococcal [Serogroups A, C, Y, and W] Conjugate Vaccine; Sanofi, Swiftwater, Pennsylvania), was approved in 2020 for the prevention of IMD caused by meningococcal serogroups A, C, W, and Y in individuals ≥2 years of age in the United States. Five pivotal studies and one ancillary study supported approval in the United States; clinical trials in infants are ongoing. Data on the immunogenicity and safety of this vaccine are presented, and its potential value in clinical practice is discussed.

Serogroup A, C, W, and Y meningococcal disease in persons previously vaccinated with a serogroup ACWY meningococcal vaccine - United States, 2014-2018

BACKGROUND

The Advisory Committee on Immunization Practices (ACIP) recommends routine vaccination with a quadrivalent meningococcal conjugate serogroup A,C,W,Y (MenACWY) vaccine at 11-12 years of age, with a booster dose at 16 years. ACIP also recommends meningococcal vaccination for persons at increased risk of meningococcal disease, including a 2-dose primary series and regular booster doses for persons at increased risk because of underlying medical conditions. U.S. cases of serogroup A, C, W, and Y meningococcal disease in persons previously vaccinated with MenACWY vaccine have not been systematically described since 2008. Characterization of these cases is important to understand potential factors leading to breakthrough disease.

METHODS

We analyzed cases of serogroup A,C,W, and Y meningococcal disease reported through the National Notifiable Diseases Surveillance System (NNDSS) from 2014 through 2018. State health departments submitted additional information on risk factors and clinical course.

RESULTS

During 2014-2018, 822 cases of serogroup A, C, W, and Y meningococcal disease were reported through NNDSS; 34 (4%) were in patients who previously received ≥ 1 dose of MenACWY vaccine. Twenty-three vaccinated patients were up-to-date on MenACWY vaccine per recommendations, and seven were not up-to-date; four were missing information on the number of doses received. Seventeen cases (50%) occurred > 3 years after the most recent dose. A significantly higher proportion of vaccinated patients were people living with HIV (PLWH) compared to unvaccinated patients. Eight of the 34 vaccinated patients were immunosuppressed, including five PLWH, one taking eculizumab, and two taking other immunosuppressive medications. The case fatality ratio did not differ between vaccinated and unvaccinated patients.

CONCLUSIONS

Immunosuppression, incomplete vaccination, and waning immunity likely contributed to breakthrough cases of meningococcal disease among people who received MenACWY vaccine. Continued monitoring of serogroup A, C, W, and Y meningococcal disease in previously vaccinated persons will help inform meningococcal disease prevention efforts.

A novel vaccine to prevent meningococcal disease beyond the first year of life: an early review of MenACYW-TT

INTRODUCTION

Although quadrivalent meningococcal conjugate vaccines have been effective in preventing invasive meningococcal disease (IMD) caused by serogroups A, C, W, and Y across age groups from infants to adults, data on their efficacy and safety in adults ≥56 years of age are lacking. Moreover, multiple available quadrivalent conjugate vaccines require reconstitution prior to administration, introducing the potential for error. A novel quadrivalent meningococcal conjugate vaccine, MenACYW-TT (MenQuadfi®) was approved in 2020 for use in individuals ≥12 months of age as a single dose in the European Union and some other countries and in individuals ≥2 years of age in the United States.

AREAS COVERED

The findings of Phase II/III studies that included >6600 individuals and evaluated the immunogenicity and safety of MenACYW-TT beyond the first year of life are comprehensively summarized and discussed.

EXPERT OPINION

Extensive data on immunogenicity and safety, co-administration with routine vaccines, elicitation of robust booster responses, and significantly higher Men C responses versus monovalent MenC or MenACWY standard-of-care vaccines in toddlers suggest that MenACYW-TT may be suitable for inclusion in National Immunization Programs (NIPs) globally. The authors provide their perspectives on the clinical use of MenACYW-TT across age groups from toddlers through adults.

Vaccines against Meningococcal Diseases

Neisseria meningitidis is the main cause of meningitis and sepsis, potentially life-threatening conditions. Thanks to advancements in vaccine development, vaccines are now available for five out of six meningococcal disease-causing serogroups (A, B, C, W, and Y). Vaccination programs with monovalent meningococcal serogroup C (MenC) conjugate vaccines in Europe have successfully decreased MenC disease and carriage. The use of a monovalent MenA conjugate vaccine in the African meningitis belt has led to a near elimination of MenA disease. Due to the emergence of non-vaccine serogroups, recommendations have gradually shifted, in many countries, from monovalent conjugate vaccines to quadrivalent MenACWY conjugate vaccines to provide broader protection. Recent real-world effectiveness of broad-coverage, protein-based MenB vaccines has been reassuring. Vaccines are also used to control meningococcal outbreaks. Despite major improvements, meningococcal disease remains a global public health concern. Further research into changing epidemiology is needed. Ongoing efforts are being made to develop next-generation, pentavalent vaccines including a MenACWYX conjugate vaccine and a MenACWY conjugate vaccine combined with MenB, which are expected to contribute to the global control of meningitis.

Long-term antibody persistence after a booster dose of quadrivalent meningococcal ACWY-tetanus toxoid conjugate vaccine in healthy 5-year-old children

BACKGROUND

To provide continuing protection, available meningococcal vaccines must provide long-term persistence of circulating functional antibodies against prevalent serogroups causing invasive meningococcal disease (IMD). This study assessed antibody persistence and safety of the quadrivalent meningococcal vaccine conjugated to tetanus toxoid (MenACWY-TT) and the meningococcal serogroup C vaccine conjugated to Corynebacterium diphtheriae CRM₁₉₇ protein (MenC-CRM) for up to 6 years after booster dosing in children.

METHODS

In the primary vaccination study, children were vaccinated at age 12 to 23 months. In the first extension study, children who completed the primary study received a booster dose 4 years later with the same primary vaccine. The current study assessed antibody persistence at 2 to 6 years postbooster against each of the 4 meningococcal serogroups using serum bactericidal assays using rabbit (rSBA) or human (hSBA) complement with antibody titer thresholds of ≥1:8 or ≥1:4, respectively, and geometric mean titers (GMTs). Safety evaluations during this period included serious adverse events (SAEs) related to vaccination and any event related to lack of vaccine efficacy.

RESULTS

A total of 184 subjects were enrolled (MenACWY-TT = 159; MenC-CRM = 25). For MenACWY-TT, the percentages of subjects with rSBA titers ≥1:8 ranged from 96.7% to 100% across serogroups at 2 years postbooster and 71.6% to 94.0% at 6 years postbooster; rSBA GMTs decreased from Year 2 to 4 and generally remained stable thereafter. The percentages of subjects in the MenACWY-TT group with hSBA titers ≥1:4 were 70.0% to 100% across serogroups at 2 years postbooster and 58.5% to 98.5% at 6 years postbooster. No lack of efficacy, SAEs, or vaccine-related adverse events were reported.

CONCLUSIONS

The persistence of rSBA and hSBA antibodies was shown up to 6 years postbooster (10 years postprimary vaccination) with either MenACWY-TT or MenC-CRM, suggesting that this schedule may provide long-term protection against IMD. Clinicaltrials.gov: NCT01900899.

Effectiveness of a single dose of the quadrivalent meningococcal conjugate vaccine, MenACWY-CRM, in the Korean Armed Forces

Conjugate vaccines are widely used to overcome the disadvantages of polysaccharide vaccines in the prevention of meningococcal disease. However, limited studies have examined the clinical effectiveness of single-dose meningococcal quadrivalent conjugate vaccines in adults. We assessed the effectiveness of the meningococcal vaccination program in the Republic of Korea Armed Forces, since 2013. Following vaccination program implementation, meningococcal disease cases decreased from 0.52/100,000 to 0.06/100,000 and the number of deaths declined from four to zero. Two meningococcal cases that developed post-implementation were identified as serotype B and X. The effectiveness of single-dose conjugate vaccination in recruits, expressed as the incidence rate ratio, was 0.88 during a 19-23-month observation period. These results indicate that meningococcal infections can be prevented by single-dose administration of the quadrivalent conjugate vaccine in at-risk groups, such as soldiers, travelers, and students in dormitories. Continuous investigation is needed to determine serogroup change, including B serogroups.

Serum Bactericidal Antibody Responses of Students Immunized With a Meningococcal Serogroup B Vaccine in Response to an Outbreak on a University Campus

Background

MenB-4C is a recently licensed meningococcal serogroup B vaccine. For vaccine licensure, short-term efficacy was inferred from serum bactericidal antibody (SBA) titers against 3 antigen-specific indicator strains, which are not necessarily representative of US disease-causing strains.

Methods

A total of 4923 students were immunized with MenB-4C in response to an outbreak at a university. Serum samples were obtained at 1.5-2 months from 106 students who received the recommended 2 doses and 52 unvaccinated students. Follow-up serum samples were obtained at 7 months from 42 vaccinated and 24 unvaccinated participants. SBA was measured against strains from 4 university outbreaks.

Results

At 1.5-2 months, the proportion of immunized students with protective titers ≥1:4 against an isolate from the campus outbreak was 93% (95% confidence interval [CI], 87%-97%) vs 37% (95% CI, 24%-51%) in unvaccinated students. The proportion with protective titers against strains from 3 other university outbreaks was 73% (95% CI, 62%-82%) vs 26% (95% CI, 14%-41%) in unvaccinated; 71% (95% CI, 61%-79%) vs 19% (95% CI, 10%-33%) in unvaccinated; and 53% (95% CI, 42%-64%) vs 9% (95% CI, 3%-22%) in unvaccinated (P < .0001 for each strain). At 7 months, the proportion of immunized students with titers ≥1:4 was 86% (95% CI, 71%-95%) against the isolate from the campus outbreak and 57% (95% CI, 41%-72%), 38% (95% CI, 24%-54%), and 31% (95% CI, 18%-47%), respectively, for the other 3 outbreak strains.

Conclusions

MenB-4C elicited short-term protective titers against 4 strains responsible for recent university campus outbreaks. By 7 months the prevalence of protective titers was <40% for 2 of the 4 outbreak strains. A booster dose of MenB-4C may be needed to maintain protective titers.

Immunogenicity and Safety of a Quadrivalent Meningococcal ACWY-tetanus Toxoid Conjugate Vaccine 6 Years After MenC Priming as Toddlers

BACKGROUND

We assessed immunogenicity, antibody persistence and safety of the meningococcal serogroups A, C, W and Y-tetanus toxoid (TT) conjugate vaccine (MenACWY-TT) in children primed as toddlers with MenC vaccine.

METHODS

This open, multicenter extension study enrolled children 84-95 months of age who had received one dose of the combined Haemophilus influenzae type b (Hib)-MenC-TT conjugate vaccine (HibMenC group) or Hib-TT and monovalent MenC (MCC)-CRM197 vaccines (Hib+MCC group) at 12-18 months of age, in the primary study. All participants received one dose of MenACWY-TT. We assessed immunogenicity against MenA, MenC, MenW and MenY at 1 month and 2 years postvaccination by serum bactericidal assay using baby rabbit complement (rSBA). Safety and reactogenicity were evaluated.

RESULTS

Six years post-MenC vaccination, <20% of children retained rSBA-MenC titers ≥1:8. At 1 month post-MenACWY-TT vaccination, vaccine response rates against all serogroups were high for both groups with ≥97.1% of children having rSBA ≥1:8. Two years postvaccination, ≥63.6% of children retained rSBA-MenA ≥1:8, and ≥87.9% for other serogroups. Geometric mean titers for all serogroups declined at 2 years post-MenACWY-TT vaccination, but remained ≥13 times higher than prevaccination levels. For both groups, pain (≤58.5%), redness (≤51.4%) and fatigue (≤27.0%) were the most frequently reported adverse events. No serious adverse events were reported.

CONCLUSIONS

One dose of MenACWY-TT boosts protection against MenC in primed children, is safe and extends protection against MenA, MenW and MenY. Immunogenicity and safety were comparable in infants vaccinated with conjugated vaccine (HibMenC-TT) or the separate vaccines (Hib-TT and MCC-CRM197).

An update of clinical experience with the quadrivalent meningococcal ACWY-CRM conjugate vaccine

INTRODUCTION

Menveo, quadrivalent meningococcal ACWY-CRM conjugate vaccine, was first licensed in 2010 in the United States and has a long track record of immunogenicity and safety in all age groups, including infants from 2 months of age.

AREAS COVERED

This review presents clinical and post-marketing experience with MenACWY-CRM from 32 studies conducted in 20 countries that included individuals aged from 2 months to 75 years.

EXPERT COMMENTARY

This decade has seen an increased number of countries reporting serogroup W ST-11 clonal complex outbreaks of invasive meningococcal disease. As infant vaccination programs targeting the meningococcus are reevaluated, the role of quadrivalent meningococcal vaccines including MenACWY-CRM will be expanded. MenACWY-CRM was immunogenic in all populations and age groups studied, regardless of country of origin. MenACWY-CRM can be coadministered with many routinely used infant, toddler and adolescent vaccines, and traveler vaccines in adults, allowing for flexible use within national immunization programs and recommendations. Antibody persistence has been demonstrated up to 5 years post vaccination in all age groups. Booster doses induced robust increases in antibody titers for all four serogroups, indicative of effective priming and induction of immunological memory. The acceptable safety profile of MenACWY-CRM has been confirmed in large post-marketing safety studies.

Characterization of strains of Neisseria meningitidis causing meningococcal meningitis in Mozambique, 2014: Implications for vaccination against meningococcal meningitis

INTRODUCTION

In sub Saharan Africa, the epidemiology, including the distribution of serogroups of strains of N. meningitidis is poorly investigated in countries outside "the meningitis belt". This study was conducted with the aim to determine the distribution of serogroups of strains of N. meningitidis causing meningococcal meningitis in children and adults in Mozambique.

METHODS

A total of 106 PCR confirmed Neisseria meningitidis Cerebrospinal Fluid (CSF) samples or isolates were obtained from the biobank of acute bacterial meningitis (ABM) surveillance being implemented by the National Institute of Health, at three central hospitals in Mozambique, from January to December 2014. Serogroups of N. meningitidis were determined using conventional PCR, targeting siaD gene for Neisseria meningitidis. Outer Membrane Proteins (OMP) Genotyping was performed by amplifying porA gene in nine samples.

RESULTS

Of the 106 PCR confirmed Neisseria meningitidis samples, the most frequent serotype was A (50.0%, 53/106), followed by W/Y (18.9%, 20/106), C (8.5%, 9/106), X (7.5%, 8/106) and B (0.9%, 1/106). We found non-groupable strains in a total of 15 (14.2%) samples. PorA genotypes from nine strains showed expected patterns with the exception of two serogroup C strains with P1.19,15,36 and P1.19-36,15 and one serogroup X with P1.19,15,36, variants frequently associated to serogroup B.

CONCLUSION

Our data shows that the number of cases of meningococcal meningitis routinely reported in central hospitals in Mozambique is significant and the most dominant serogroup is A. In conclusion, although serogroup A has almost been eliminated from the "meningitis belt", this serogroup remains a major concern in countries outside the belt such as Mozambique.

A Safety and Immunogenicity Study of a Single Dose of a Meningococcal (Groups A, C, W, and Y) Polysaccharide Diphtheria Toxoid Conjugate Vaccine (MEN-ACWY-D) in Healthy Japanese Participants

Meningococcal disease can cause significant disability and mortality. The quadrivalent meningococcal polysaccharide diphtheria toxoid conjugate vaccine (Men-ACWY-D) protects against invasive meningococcal disease caused by serogroups A, C, W, and Y. This phase III, open-label, single-arm, multicenter study evaluated the safety and immunogenicity of a single vaccine dose in healthy Japanese adults. The study enrolled 200 participants between 2 and 55 years of age. Immunogenicity was assessed by quantifying the seroprotection rates (the proportion of participants with antibody titers ≥ 1:128 against the capsular polysaccharide from all 4 serogroups measured 28 days after vaccination). Safety endpoints included occurrence, nature, time to onset, duration, intensity, relationship to vaccination, and outcome of solicited and unsolicited adverse events (AEs) and serious AEs (SAEs). Participants included 194 adults, 2 adolescents, and 4 children. Among adults, the seroprotection rates for serogroups A, C, W, and Y were 91.2%, 80.2%, 89.1%, and 93.8%, respectively. Seroconversion rates (the proportion of participants with pre-vaccination titers of < 1:4 and a ≥ 4-fold rise from baseline) were 87.3%, 83.0%, 94.4%, and 96.4%, respectively. No immediate AEs, adverse reactions, SAEs, or deaths were reported for any age group. Men-ACWY-D is well tolerated and immunogenic, eliciting antibodies against capsular polysaccharides from all 4 serogroups in Japanese adults.

Clinical data supporting a 2-dose schedule of MenB-FHbp, a bivalent meningococcal serogroup B vaccine, in adolescents and young adults

Invasive meningococcal disease (IMD) caused by Neisseria meningitidis is a potentially devastating condition that can result in death and is associated with serious long-term sequelae in survivors. Vaccination is the preferred preventative strategy. Quadrivalent polysaccharide-based vaccines that protect against infection caused by meningococcal serogroups A, C, W, and Y are not effective against meningococcal serogroup B (MenB), which was responsible for approximately 60% and 35% of confirmed IMD cases in the European Union and the United States in 2016, respectively. A recombinant protein MenB vaccine (MenB-FHbp [bivalent rLP2086; Trumenba®]) has been approved for protection against MenB infection in persons 10-25 years of age in the United States and Canada and for individuals ≥10 years of age in the European Union and Australia. In these regions, MenB-FHbp is approved as a 2- or 3-dose primary vaccination schedule. This report will review the current evidence supporting administration of MenB-FHbp as a 2-dose primary vaccination schedule. Different contexts in which a 2- or 3-dose primary vaccination schedule might be preferred (eg, routine prospective vaccination vs outbreak control) are reviewed.

Cost-effectiveness Comparison of Monovalent C Versus Quadrivalent ACWY Meningococcal Conjugate Vaccination in Canada

BACKGROUND

In Quebec, 1 dose of monovalent C meningococcal conjugate vaccine (Men-C-Con) is offered at 12 months of age and a booster dose in grade 9 (14-15 years of age). In other Canadian provinces, a quadrivalent vaccine against serogroups ACWY (Men-4-Con) is increasingly used for adolescents. An economic analysis was performed to assess the value of a switch from Men-C-Con to Men-4-Con.

METHODS

A compartmental static simulation model was developed to assess the burden of invasive meningococcal disease due to serogroups AWY (AWY-IMD) in a cohort of 100,000 persons with different vaccination programs. Univariate and multivariate sensitivity analyses were performed, including variation in vaccine price difference ($12; range: $0-$20), AWY-IMD rate (0.08/100,000 to 0.28/100,000 person-years), level of herd immunity generated by adolescent vaccination (from zero to disease elimination) and discounting rate (0%, 3% or 6%).

RESULTS

In the low AWY-IMD rate base scenario, replacing Men-C-Con by Men-4-Con for adolescents would reduce disease burden by 16% (no herd effect) to 58% (moderate herd effect), with an incremental cost-effectiveness ratios between $445,000 per quality-adjusted life-year (QALY) and $167,000/QALY in a societal perspective. In the high AWY-IMD rate scenario, incremental cost-effectiveness ratio would be in the range of $97,000/QALY to $19,000/QALY.

CONCLUSION

Based on the epidemiologic conditions in Quebec and in most other Canadian provinces, the benefits of Men-4-Con in reducing the burden of disease would be low for a high cost. The switch would, however, be more economically attractive with a much higher incidence rate (as in a few provinces) or with a reduced vaccine price in conditions assuming a moderate to high herd effect.

Effectiveness and Duration of Protection of One Dose of a Meningococcal Conjugate Vaccine

BACKGROUND

Meningococcal conjugate vaccines were licensed beginning in 2005 on the basis of serologic end points and recommended for use in adolescents. A single dose at age 11 to 12 years was expected to provide protection through late adolescence. We conducted a case-control evaluation of vaccine effectiveness (VE) and duration of protection of a meningococcal (groups A, C, W, and Y) polysaccharide diphtheria toxoid conjugate vaccine (MenACWY-D).

METHODS

Cases of culture- or polymerase chain reaction-confirmed serogroup A, C, W, and Y meningococcal disease among adolescents were identified through meningococcal disease surveillance sites in the United States from January 1, 2006, through August 31, 2013. Attempts were made to enroll 4 friend and school controls per case. VE was calculated using the generalized estimating equation, controlling for underlying medical conditions and smoking.

RESULTS

Serogroup C accounted for 88 (49%), serogroup Y 80 (44%), and serogroup W 13 (7%) of enrolled cases. Thirty-six (20%) cases and 87 (44%) controls received MenACWY-D. The overall VE estimate 0 to 8 years postvaccination was 69% (51% to 80%); VE was 79% (49% to 91%) at <1 year, 69% (44% to 83%) at 1 to <3 years, and 61% (25% to 79%) at 3 to <8 years. VE was 77% (57% to 88%) against serogroup C and 51% (1% to 76%) against serogroup Y.

CONCLUSIONS

MenACWY-D was effective in the first year after vaccination but effectiveness waned 3 to <8 years postvaccination. The estimates of VE from this evaluation informed the Advisory Committee on Immunization Practices in its decision to add a booster dose of MenACWY.

Cost-Effectiveness of Meningococcal Vaccination Among Men Who Have Sex With Men in New York City

BACKGROUND

To control an outbreak of invasive meningococcal disease (IMD) among men who have sex with men (MSM) in New York City, the New York City Department of Health and Mental Hygiene recommended vaccination of all HIV-infected MSM and at-risk HIV-uninfected MSM in October 2012.

METHODS

A decision-analytic model estimated the cost-effectiveness of meningococcal vaccination compared with no vaccination. Model inputs, including IMD incidence of 20.5 per 100,000 HIV-positive MSM (42% fatal) and 7.6 per 100,000 HIV-negative MSM (20% fatal), were from Department of Health and Mental Hygiene reported data and published sources. Outcomes included costs (2012 US dollars), IMD cases averted, IMD deaths averted, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs; $/QALY). Scenarios with and without herd immunity were considered, and sensitivity analyses were performed on key inputs.

RESULTS

Compared with no vaccination, the targeted vaccination campaign averted an estimated 2.7 IMD cases, 1.0 IMD deaths, with an ICER of $66,000/QALY when herd immunity was assumed. Without herd immunity, vaccination prevented 1.1 IMD cases, 0.4 IMD deaths, with an ICER of $177,000/QALY. In one-way sensitivity analyses, variables that exerted the greatest influence on results in order of effect were the magnitude of herd immunity, IMD case fatality ratio, and IMD incidence. In probabilistic sensitivity analyses, at a cost-effectiveness threshold of $100,000/QALY, vaccination was preferred in 97% of simulations with herd immunity and 20% of simulations without herd immunity.

CONCLUSIONS

Vaccination during an IMD outbreak among MSM with and without HIV infection was projected to avert IMD cases and deaths and could be cost-effective depending on IMD incidence, case fatality, and herd immunity.

Five-year Antibody Persistence and Booster Response After 1 or 2 Doses of Meningococcal A, C, W and Y Tetanus Toxoid Conjugate Vaccine in Healthy Children

BACKGROUND

We evaluated antibody persistence up to 5 years postvaccination with a quadrivalent meningococcal serogroups A, C, W and Y tetanus toxoid conjugate vaccine (MenACWY-TT), and subsequent booster responses to MenACWY-TT in healthy US children.

METHODS

In the initial phase II, open, multicenter study (NCT00471081), 349 infants were randomized (1:1) to receive MenACWY-TT (1 or 2 doses). In the follow-up study (NCT00718666), we evaluated antibody persistence at years 1, 3 and 5 by serum bactericidal assay using human complement (hSBA). At year 5, children received a booster dose of MenACWY-TT. We compared their immune responses at 1 month postbooster with those from 100 age-matched, meningococcal naive children, who received a primary MenACWY-TT dose. We recorded solicited adverse events for 4 days and unsolicited adverse events for 31 days, followed by an additional 5-month extended safety follow-up.

RESULTS

At year 5, ≥64.0% of 1-dose and ≥74.6% of 2-dose recipients had hSBA titers ≥8 for MenC, MenW and MenY. For MenA, 31.7% of 1-dose and 38.0% of 2-dose recipients had hSBA titers ≥8. One month postvaccination, all booster dose recipients and ≥78.5% of primary dose recipients exhibited hSBA titers ≥8 for all serogroups. Geometric mean titers were higher in primed than in naive children. MenACWY-TT had a clinically acceptable safety profile.

CONCLUSIONS

With the exception of serogroup W, antibody persistence 5 years after MenACWY-TT vaccination did not differ substantially between children who received 1 or 2 doses in infancy. A booster dose of MenACWY-TT elicited robust anamnestic responses and was well tolerated.

Effect of Culture-Independent Diagnostic Tests on Future Emerging Infections Program Surveillance

The Centers for Disease Control and Prevention Emerging Infections Program (EIP) network conducts population-based surveillance for pathogens of public health importance. Central to obtaining estimates of disease burden and tracking microbiological characteristics of these infections is accurate laboratory detection of pathogens. The use of culture-independent diagnostic tests (CIDTs) in clinical settings presents both opportunities and challenges to EIP surveillance. Because CIDTs offer better sensitivity than culture and are relatively easy to perform, their use could potentially improve estimates of disease burden. However, changes in clinical testing practices, use of tests with different sensitivities and specificities, and changes to case definitions make it challenging to monitor trends. Isolates are still needed for performing strain typing, antimicrobial resistance testing, and identifying other molecular characteristics of organisms. In this article, we outline current and future EIP activities to address issues associated with adoption of CIDTs, which may apply to other public health surveillance.

Meningococcal disease epidemiology in Australia 10 years after implementation of a national conjugate meningococcal C immunization programme

Australia implemented conjugate meningococcal C immunization in 2003 with a single scheduled dose at age 12 months and catch-up for individuals aged 2–19 years. Several countries have recently added one or more booster doses to their programmes to maintain disease control. Australian disease surveillance and vaccine coverage data were used to assess longer term vaccine coverage and impact on invasive serogroup C disease incidence and mortality, and review vaccine failures. Coverage was 93% in 1-year-olds and 70% for catch-up cohorts. In 10 years, after adjusting for changes in diagnostic practices, population invasive serogroup C incidence declined 96% (95% confidence interval 94–98) to 0·4 and 0·6 cases/million in vaccinated and unvaccinated cohorts, respectively. Only three serogroup C deaths occurred in 2010–2012vs.68 in 2000–2002. Four (<1/million doses) confirmed vaccine failures were identified in 10 years with no increasing trend. Despite published evidence of waning antibody over time, an ongoing single dose of meningococcal C conjugate vaccine in the second year of life following widespread catch-up has resulted in near elimination of serogroup C disease in all age groups without evidence of vaccine failures in the first decade since introduction. Concurrently, serogroup B incidence declined independently by 55%.

Routinely vaccinating adolescents against meningococcus: targeting transmission & disease

Adolescents have the highest rates of meningococcal carriage and transmission. Interrupting the adolescent habitat in order to reduce carriage and transmission within adolescents and to other age groups could help to control meningococcal disease at a population level. Compared to immunization strategies restricted to young children, a strategy focused on adolescents may have more profound and long-lasting indirect impacts, and may be more cost effective. Despite challenges in reaching this age-group, experience with other vaccines show that high vaccine coverage of adolescents is attainable.

Safety and immunogenicity of a single dose of a quadrivalent meningococcal conjugate vaccine (MenACYW-D): a multicenter, blind-observer, randomized, phase III clinical trial in the Republic of Korea

OBJECTIVES

To assess the safety and immunogenicity of a meningococcal polysaccharide diphtheria toxoid conjugate vaccine (MenACYW-D) in a Korean population.

METHODS

This was a phase III, blind-observer, controlled study in which participants aged 11-55 years were randomized (2:1 ratio) to a single dose of MenACYW-D or tetanus/diphtheria/acellular pertussis (Tdap) vaccine. Outcomes included rates of seroconversion against all serogroups (≥4-fold increase in antibody titer from pre-vaccination), geometric mean titers (GMTs) at days 0 and 28 based on a serum bactericidal assay using baby rabbit complement, rates of seroprotection (titer ≥1:128) at day 28, and safety.

RESULTS

A total of 300 participants were enrolled in the study (200 MenACYW-D and 100 Tdap). Seroconversion rates for serogroups A, C, Y, and W-135 were 77.8%, 88.3%, 74.6%, and 92.4%, respectively, for the MenACYW-D group and 9.3%, 8.1%, 12.2%, and 8.2%, respectively, for the Tdap group. The proportions of participants with pre-vaccination titers ≥1:128 were 57.3%, 12.6%, 51.5%, and 22.2% for serogroups A, C, Y, and W-135, respectively; post-vaccination rates were 98.5%, 89.4%, 96.0%, and 95.0% for the MenACYW-D group. A lower proportion of participants reported solicited reactions with MenACYW-D (46.2%) compared with Tdap (76.8%).

CONCLUSION

A single dose of MenACYW-D was well tolerated and elicited a robust immune response in Korean adolescents and adults.

Invasive meningococcal disease in the 21st century—an update for the clinician

Neisseria meningitidis is a gram-negative diplococcus, for which humans are the only reservoir. While colonization is common, invasive meningococcal disease in the form of meningitis or bacteremia can be devastating and potentially fatal. Certain populations are at higher risk for disease including infants, adolescents, those with asplenia or complement deficiencies, and potentially those with human immunodeficiency virus (HIV) infection. Use of conjugate meningococcal vaccines has impacted disease epidemiology in both high- and low-income countries. Outbreaks of serogroup B disease at university campuses have drawn further attention to the recent development of a novel serogroup B vaccine now approved in many countries. This review covers key aspects of the pathogenesis and management of meningococcal disease, as well as the very recent developments in disease epidemiology, outbreaks, and the evolution of meningococcal immunizations.

Vaccination of adolescents with chronic medical conditions: Special considerations and strategies for enhancing uptake

Adolescents with chronic medical conditions (CMCs), a growing population worldwide, possess a wide array of preventive health care needs. Vaccination is strongly recommended for the vast majority of these adolescents given their increased risk of vaccine preventable infection and associated complications. Not only should they receive routine vaccines, but some also require additional vaccines. Despite these guidelines, evidence suggests that adolescents with CMCs often fail to receive needed vaccines. Many factors contribute to this under-immunization, including lack of knowledge among parents and providers and suboptimal coordination of primary and subspecialty care. This review describes current vaccination recommendations for these adolescents as well as recent data related to infection risk, vaccine efficacy and safety, vaccination coverage, and the unique multilevel factors impacting uptake in this population. It also discusses strategies for improving coverage levels and reducing missed vaccination opportunities, with a particular focus on technology-based interventions.

Bridging non-human primate correlates of protection to reassess the Anthrax Vaccine Adsorbed booster schedule in humans

Anthrax Vaccine Adsorbed (AVA, BioThrax) is approved for use in humans as a priming series of 3 intramuscular (i.m.) injections (0, 1, 6 months; 3-IM) with boosters at 12 and 18 months, and annually thereafter for those at continued risk of infection. A reduction in AVA booster frequency would lessen the burden of vaccination, reduce the cumulative frequency of vaccine associated adverse events and potentially expand vaccine coverage by requiring fewer doses per schedule. Because human inhalation anthrax studies are neither feasible nor ethical, AVA efficacy estimates are determined using cross-species bridging of immune correlates of protection (COP) identified in animal models. We have previously reported that the AVA 3-IM priming series provided high levels of protection in non-human primates (NHP) against inhalation anthrax for up to 4 years after the first vaccination. Penalized logistic regressions of those NHP immunological data identified that anti-protective antigen (anti-PA) IgG concentration measured just prior to infectious challenge was the most accurate single COP. In the present analysis, cross-species logistic regression models of this COP were used to predict probability of survival during a 43 month study in humans receiving the current 3-dose priming and 4 boosters (12, 18, 30 and 42 months; 7-IM) and reduced schedules with boosters at months 18 and 42 only (5-IM), or at month 42 only (4-IM). All models predicted high survival probabilities for the reduced schedules from 7 to 43 months. The predicted survival probabilities for the reduced schedules were 86.8% (4-IM) and 95.8% (5-IM) at month 42 when antibody levels were lowest. The data indicated that 4-IM and 5-IM are both viable alternatives to the current AVA pre-exposure prophylaxis schedule.

Indian Academy of Pediatrics (IAP) recommended immunization schedule for children aged 0 through 18 years, India, 2013 and updates on immunization

JUSTIFICATION

There is a need to review/revise recommendations about existing vaccines in light of recent developments in the field of vaccinology where new developments are taking place regularly at short intervals.

PROCESS

Following an IAP ACVIP meeting on 3rd and 4th August, 2013, a draft of revised recommendations for the year 2013 and updates on certain new vaccine formulations was prepared and circulated among the meeting participants to arrive at a consensus.

OBJECTIVES

To review and revise recommendations for 2013 Immunization timetable for pediatricians in office practice and issue statements on new vaccine formulations.

RECOMMENDATIONS

The major change in the 2013 Immunization timetable was made in the recommendations pertaining to pertussis immunization. Taking in to the consideration of recent outbreaks of pertussis in many industrialized countries using acellular pertussis (aP) vaccines and subsequent finding of faster waning of the same in comparison to whole-cell pertussis (wP) vaccines and superior priming with wP vaccines than aP vaccines, the committee has now recommended wP vaccines for the primary series of infant vaccination. Guidelines are now also issued on the preference/selection of a particular aP vaccine in case it is not feasible to use wP vaccine, and use of Tdap vaccine during pregnancy. The administration schedule of monovalent human rotavirus vaccine, RV1 has been revised to 10 and 14 weeks from existing 6 and 10 weeks. Recommendation is made for the need of booster dose of live attenuated SA-14-14-2 JE vaccine. Updates and recommendations are issued on new typhoid conjugate vaccine, inactivated vero-cell culture derived SA-14-14-2 JE vaccine, inactivated vero-cell derived Kolar strain, 821564XY JE vaccine, and new meningococcal conjugate vaccines. This year the recommended immunization schedule with range for persons aged 0 through 18 years is being published together instead of two separate schedules. A subcategory of general instruction is added in footnotes. The comments and footnotes for several vaccines are revised and separate instructions for routine vaccination and catch-up vaccination are added in the footnotes section wherever applicable.

Role of factor H binding protein in Neisseria meningitidis virulence and its potential as a vaccine candidate to broadly protect against meningococcal disease

Neisseria meningitidis is a Gram-negative microorganism that exists exclusively in humans and can cause devastating invasive disease. Although capsular polysaccharide-based vaccines against serogroups A, C, Y, and W135 are widely available, the pathway to a broadly protective vaccine against serogroup B has been more complex. The last 11 years has seen the discovery and development of the N. meningitidis serogroup B (MnB) outer membrane protein factor H binding protein (fHBP) as a vaccine component. Since the initial discovery of fHBP, a tremendous amount of work has accumulated on the diversity, structure, and regulation of this important protein. fHBP has proved to be a virulence factor for N. meningitidis and a target for functional bactericidal antibodies. fHBP is critical for survival of meningococci in the human host, as it is responsible for the primary interaction with human factor H (fH). Binding of hfH by the meningococcus serves to downregulate the host alternative complement pathway and helps the organism evade host innate immunity. Preclinical studies have shown that an fHBP-based vaccine can elicit serum bactericidal antibodies capable of killing MnB, and the vaccine has shown very encouraging results in human clinical trials. This report reviews our current knowledge of fHBP. In particular, we discuss the recent advances in our understanding of fHBP, its importance to N. meningitidis, and its potential role as a vaccine for preventing MnB disease.

Meningococcal serogroups A, C, W-135, and Y tetanus toxoid conjugate vaccine: a new conjugate vaccine against invasive meningococcal disease

Invasive meningococcal disease is a serious infection that occurs worldwide. It is caused by Neisseria meningitidis, of which six serogroups (A, B, C, W-135, X, and Y) are responsible for most infections. The case fatality rate of meningococcal disease remains high and can lead to significant sequelae. Vaccination remains the best strategy to prevent meningococcal disease. Polysaccharide vaccines were initially introduced in the late 1960s but their limitations (poor immunogenicity in infants and toddlers and hyporesponsiveness after repeated doses) have led to the development and use of meningococcal conjugate vaccines, which overcome these limitations. Two quadrivalent conjugated meningococcal vaccines – MenACWY-DT (Menactra^®) and MenACWY-CRM₁₉₇ (Menveo^®) – using diphtheria toxoid or a mutant protein, respectively, as carrier proteins have already been licensed in the US. Recently, a quadrivalent meningococcal vaccine conjugated to tetanus toxoid (MenACWY-TT; Nimenrix^®) was approved for use in Europe in 2012. The immunogenicity of MenACWY-TT, its reactogenicity and safety profile, as well as its coadministration with other vaccines are discussed in this review. Clinical trials showed that MenACWY-TT was immunogenic in children above the age of 12 months, adolescents, and adults, and has an acceptable reactogenicity and safety profile. Its coadministration with several other vaccines that are commonly used in children, adolescents, and adults did not affect the immunogenicity of MenACWY-TT or the coadministered vaccine, nor did it affect its reactogenicity and safety. Other studies are now ongoing in order to determine the immunogenicity, reactogenicity, and safety of MenACWY-TT in infants from the age of 6 weeks.

Protein carriers of conjugate vaccines: characteristics, development, and clinical trials

The immunogenicity of polysaccharides as human vaccines was enhanced by coupling to protein carriers. Conjugation transformed the T cell-independent polysaccharide vaccines of the past to T cell-dependent antigenic vaccines that were much more immunogenic and launched a renaissance in vaccinology. This review discusses the conjugate vaccines for prevention of infections caused by Hemophilus influenzae type b, Streptococcus pneumoniae, and Neisseria meningitidis. Specifically, the characteristics of the proteins used in the construction of the vaccines including CRM, tetanus toxoid, diphtheria toxoid, Neisseria meningitidis outer membrane complex, and Hemophilus influenzae protein D are discussed. The studies that established differences among and key features of conjugate vaccines including immunologic memory induction, reduction of nasopharyngeal colonization and herd immunity, and antibody avidity and avidity maturation are presented. Studies of dose, schedule, response to boosters, of single protein carriers with single and multiple polysaccharides, of multiple protein carriers with multiple polysaccharides and conjugate vaccines administered concurrently with other vaccines are discussed along with undesirable consequences of conjugate vaccines. The clear benefits of conjugate vaccines in improving the protective responses of the immature immune systems of young infants and the senescent immune systems of the elderly have been made clear and opened the way to development of additional vaccines using this technology for future vaccine products.

Update on adolescent immunizations: selected review of US recommendations and literature

PURPOSE OF REVIEW

To provide a clinically relevant synopsis of recent research findings as well as updated recommendations from the American Academy of Pediatrics (AAP) and Advisory Committee on Immunization Practices (ACIP) regarding adolescent immunizations.

RECENT FINDINGS

Coverage rates for the adolescent vaccinations continue to lag behind those of the childhood vaccinations, despite their importance. Recent research has focused on the reasons for suboptimal adolescent vaccination rates as well as strategies for improvement. By more fully understanding the barriers to immunization, efforts can be implemented to address these concerns and to ensure that all eligible adolescents receive their vaccinations. In addition, much work has focused on the duration of protection induced by childhood and adolescent vaccinations and the need for booster doses in older adolescents. Because immunity has been found to wane after vaccination, these booster doses can serve to more fully protect adolescents. This article reviews selected recent publications on human papillomavirus, meningococcal conjugate, and tetanus and diphtheria toxoids and acellular pertussis vaccines.

SUMMARY

Adolescent vaccinations will continue to be studied and this research will serve to shape future recommendations. Through this work, we can learn the best methods to optimize the protection of all adolescents against these very serious diseases.

The changing epidemiology of meningococcal disease in North America 1945-2010

The epidemiology of Invasive Meningococcal Disease (IMD) is distinct in the United States and Canada compared with other countries. This review describes the incidence, mortality and vaccination strategies relevant to IMD in these countries over the past 65 y. The incidence of IMD has remained consistently low in both countries during this period. Serogroup B and serogroup C have been the most prominent disease-causing serogroups. Notably, serogroup Y has recently become an important cause of IMD in the USA, but has not been as prominent in Canada. Periodic rises in incidence have been characterized by local outbreaks that have raised public concern, especially those caused by serogroup C in Canada, and serogroup B in the USA. Case fatality rates have remained consistent at around 10-20%, but vary by age and serogroup. Recent outbreaks have led to the introduction of vaccination programs for both outbreak control and routine immunization.

MenACWY-TT vaccine for active immunization against invasive meningococcal disease

Meningococcal disease remains a significant global cause of morbidity and mortality despite the availability of polysaccharide and conjugate vaccines. The implementation of monovalent meningococcal serogroup C vaccine in developed countries has significantly decreased the incidence of meningococcal disease, while the recent introduction of monovalent serogroup A conjugate vaccine in the African meningitis belt aims to reduce the incidence of high endemic disease in this area. Three quadrivalent meningococcal vaccines have already been licensed; a polysaccharide (MenACWY-PS) and two conjugated (MenACWY-DT and MenACWY-CRM) vaccines. An investigational MenACWY-TT vaccine is described in this article. Clinical trials in infants older than 9 months of age, toddlers, children, adolescents and adults have indicated that this vaccine is well tolerated and immunogenic. The inclusion of a spacer molecule coupled with the polysaccharide (for serogroups A and C) and tetanus toxoid as the carrier protein aims to elicit robust immune responses. The tolerability of this vaccine is comparable to that of polysaccharide quadrivalent vaccines and monovalent meningococcal serogroup C vaccines. More importantly, the immunogenicity, antibody persistence and induction of immune memory aim to provide protection to a wide range of susceptible subjects.

Update on child and adolescent immunizations: selected review of US recommendations and literature

PURPOSE OF REVIEW

To provide a clinically relevant synopsis of recent research findings as well as updated guidelines from the American Academy of Pediatrics and Advisory Committee on Immunization Practices regarding child and adolescent immunizations.

RECENT FINDINGS

Childhood vaccinations have served to dramatically reduce pediatric morbidity and mortality in the USA. Much of the recent research has focused on the improvement of current vaccines as well as on the development of new vaccines. By improving the safety, efficacy and immunogenicity of vaccinations, children can be more fully protected. Additionally, recommendations have broadened as vaccinations have been proven well tolerated and effective for a growing number of subpopulations. Although more groups of children are now included in vaccination recommendations, efforts must continue to ensure that all eligible children receive their vaccinations. This article reviews selected recent publications on influenza, human papillomavirus, the childhood and adolescent/adult formulations of diphtheria and tetanus toxoids and acellular pertussis, meningococcal conjugate and pneumococcal vaccines. The relationship between febrile seizures and childhood immunizations is explored.

SUMMARY

The research on childhood and adolescent vaccinations is continuously growing and will serve to shape future recommendations. Through their findings, we can learn how to optimize the protection of all children and adolescents against these very serious diseases.

A randomized trial to assess safety and immunogenicity of alternative formulations of a quadrivalent meningococcal (A, C, Y, and W-135) tetanus protein conjugate vaccine in toddlers

BACKGROUND

Neisseria meningitidis is a leading cause of meningitis and septicemia globally. Recent shifts in serogroup dominance in some settings highlight the desirability of polysaccharide-conjugate vaccines with broader meningococcal coverage than serogroup C vaccines in widespread use.

METHODS

We assessed the safety and immunogenicity of a single dose of meningococcal quadrivalent (A, C, W-135, Y) tetanus conjugate vaccine (TetraMen-T), administered at 1 year of age. A total of 378 children were randomized to 1 of 6 groups--5 received alternative formulations of TetraMen-T, the sixth licensed adjuvanted serogroup C conjugate vaccine (Neisvac-C). Solicited adverse event reports were collected from day 0 to 7 after vaccination and unsolicited and serious adverse event reports throughout study participation. Immunogenicity was assessed by serum bactericidal assays containing either a human (hSBA) or baby rabbit (rSBA) complement source before and 1 month after immunization.

RESULTS

All vaccine formulations were safe and well tolerated. Using the various measures of immunogenicity, no consistent relationships were observed between the dose of either polysaccharide or carrier and serogroup-specific response for any one antigen. The highest-dose vaccine provided optimal coverage for all 4 serogroups, with the percentage of recipients achieving hSBA titers ≥ 8 against each as follows: A, 92%; C, 96%; W-135, 71%; Y, 82% (corresponding proportions with rSBAs titers >8 all exceeded 90%). The investigational vaccines were less immunogenic against the serogroup C capsular polysaccharide than the licensed comparator.

CONCLUSIONS

Studies are ongoing that will help to identify optimal scheduling of quadrivalent meningococcal conjugate vaccines, to facilitate their inclusion into national immunization programs seeking extended serogroup coverage against meningococci.

The changing and dynamic epidemiology of meningococcal disease

The epidemiology of invasive meningococcal disease continues to change rapidly, even in the three years since the first Meningococcal Exchange Meeting in 2008. Control of disease caused by serogroup C has been achieved in countries that have implemented meningococcal C or quadrivalent meningococcal ACWY conjugate vaccines. Initiation of mass immunization programs with meningococcal A conjugate vaccines across the meningitis belt of Africa may lead to the interruption of cyclical meningococcal epidemics. A meningococcal B vaccination program in New Zealand has led to a decreased incidence of high rates of endemic serogroup B disease. Increases in serogroup Y disease have been observed in certain Nordic countries which, if they persist, may require consideration of use of a multiple serogroup vaccine. The imminent availability of recombinant broadly protective serogroup B vaccines may provide the tools for further control of invasive meningococcal disease in areas where serogroup B disease predominates. Continued surveillance of meningococcal disease is essential; ongoing global efforts to improve the completeness of reporting are required.

Meningococcal conjugate vaccines policy update: booster dose recommendations

The Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention and the American Academy of Pediatrics approved updated recommendations for the use of quadravalent (serogroups A, C, W-135, and Y) meningococcal conjugate vaccines (Menactra [Sanofi Pasteur, Swiftwater, PA] and Menveo [Novartis, Basel, Switzerland]) in adolescents and in people at persistent high risk of meningococcal disease. The recommendations supplement previous Advisory Committee on Immunization Practices and American Academy of Pediatrics recommendations for meningococcal vaccinations. Data were reviewed pertaining to immunogenicity in high-risk groups, bactericidal antibody persistence after immunization, current epidemiology of meningococcal disease, meningococcal conjugate vaccine effectiveness, and cost-effectiveness of different strategies for vaccination of adolescents. This review prompted the following recommendations: (1) adolescents should be routinely immunized at 11 through 12 years of age and given a booster dose at 16 years of age; (2) adolescents who received their first dose at age 13 through 15 years should receive a booster at age 16 through 18 years or up to 5 years after their first dose; (3) adolescents who receive their first dose of meningococcal conjugate vaccine at or after 16 years of age do not need a booster dose; (4) a 2-dose primary series should be administered 2 months apart for those who are at increased risk of invasive meningococcal disease because of persistent complement component (eg, C5-C9, properdin, factor H, or factor D) deficiency (9 months through 54 years of age) or functional or anatomic asplenia (2-54 years of age) and for adolescents with HIV infection; and (5) a booster dose should be given 3 years after the primary series if the primary 2-dose series was given from 2 through 6 years of age and every 5 years for persons whose 2-dose primary series or booster dose was given at 7 years of age or older who are at risk of invasive meningococcal disease because of persistent component (eg, C5-C9, properdin, factor H, or factor D) deficiency or functional or anatomic asplenia.

Critical appraisal of a quadrivalent CRM(197) conjugate vaccine against meningococcal serogroups A, C W-135 and Y (Menveo) in the context of treatment and prevention of invasive disease

Worldwide, invasive meningococcal disease affects about 500,000 people annually. Case fatality in developed countries averages 10%, and higher rates are reported in less prosperous regions. According to the World Health Organization, the most important pathogenic serogroups are A, B, C, W-135, X, and Y. Clinical features of invasive meningococcal disease make diagnosis and management difficult. Antibiotic measures are recommended for prophylaxis after exposure and for treatment of invasive meningococcal disease cases; however, resistant strains may be emerging. Vaccines are generally regarded as the best preventative measure for invasive meningococcal disease. Polysaccharide vaccines against serogroups A, C, W-135, and Y using protein conjugation technology have clear advantages over older plain polysaccharide formulations without a protein component. The first quadrivalent meningococcal conjugate vaccine (MenACWY-D) was licensed in the US in 2005. More recently, MenACWY-CRM (Menveo^®) was licensed in Europe, the US, the Middle East, and Latin America. MenACWY-CRM uses cross-reactive material 197, a nontoxic mutant of diphtheria toxin, as the carrier protein. MenACWY-CRM offers robust immunogenicity in all age groups, with a tolerability profile similar to that of a plain polysaccharide vaccine. Given its potential for protecting persons from infancy to old age, MenACWY-CRM offers the opportunity to protect broad populations against invasive meningococcal disease. The most optimal strategy for use of the vaccine has to be assessed country by country on the basis of local epidemiology, individual health care systems, and need.