Vaccination with a multicomponent meningococcal B vaccine in prevention of disease in adolescents and young adults

Multimodal surveillance of SARS-CoV-2 at a university enables development of a robust outbreak response framework

BACKGROUND

Universities are vulnerable to infectious disease outbreaks, making them ideal environments to study transmission dynamics and evaluate mitigation and surveillance measures. Here, we analyze multimodal COVID-19-associated data collected during the 2020-2021 academic year at Colorado Mesa University and introduce a SARS-CoV-2 surveillance and response framework.

METHODS

We analyzed epidemiological and sociobehavioral data (demographics, contact tracing, and WiFi-based co-location data) alongside pathogen surveillance data (wastewater and diagnostic testing, and viral genomic sequencing of wastewater and clinical specimens) to characterize outbreak dynamics and inform policy. We applied relative risk, multiple linear regression, and social network assortativity to identify attributes or behaviors associated with contracting SARS-CoV-2. To characterize SARS-CoV-2 transmission, we used viral sequencing, phylogenomic tools, and functional assays.

FINDINGS

Athletes, particularly those on high-contact teams, had the highest risk of testing positive. On average, individuals who tested positive had more contacts and longer interaction durations than individuals who never tested positive. The distribution of contacts per individual was overdispersed, although not as overdispersed as the distribution of phylogenomic descendants. Corroboration via technical replicates was essential for identification of wastewater mutations.

CONCLUSIONS

Based on our findings, we formulate a framework that combines tools into an integrated disease surveillance program that can be implemented in other congregate settings with limited resources.

FUNDING

This work was supported by the National Science Foundation, the Hertz Foundation, the National Institutes of Health, the Centers for Disease Control and Prevention, the Massachusetts Consortium on Pathogen Readiness, the Howard Hughes Medical Institute, the Flu Lab, and the Audacious Project.

Immunogenicity of a single 4CMenB vaccine booster in adolescents 11 years after childhood immunisation

The clinical development of the meningococcal vaccine, 4CMenB, included 2 doses in vaccine-naïve adolescents, which was considered unlikely to be cost-effective for implementation. Theoretically, priming with 4CMenB in early childhood might drive strong immune responses after only a single booster dose in adolescents and reduce programmatic costs. To address this question, children over 11 years old who took part in previous trials involving the administration of 3-5 doses of 4CMenB at infant/preschool age from 2006 were recruited into a post licensure single-centre trial, and were divided into two groups: those who received their last dose at 12 months old (infant group) and those who received their last dose at 3 years old (infant + preschool group). Naïve age-matched controls were randomised to receive one (adolescent 1 group) or two doses at days 0 and 28 (adolescent 2 group) of 4CMenB. Serum bactericidal antibody (SBA) assays using human complement were performed against three reference strains prior to vaccination, and at 1, 6 and 12 months. Previous vaccination was associated with a higher response to a single booster dose at 11 years of age, one-month post-vaccination, when compared with a single dose in naïve age-matched controls. At day 180, the highest responses were observed in participants in the infant + preschool group against strain 5/99 (GMT 316.1 [CI 158.4 to 630.8]), as compared with naïve adolescents who received two doses (GMTs 84.5 [CI 57.7 to 123.6]). When the last dose was received at 12-months of age, responses to a single adolescent dose were not as robust (GMT 61.1 [CI 14.8 to 252.4] to strain 5/99). This descriptive study indicates that the highest SBA responses after a single dose in adolescence were observed in participants who received a preschool dose, suggesting that B cell memory responses are not sufficiently primed at less than 12 months of age. Trial registration EudraCT 2017-004732-11, ISRCTN16774163.

Response to a Serogroup B Meningococcal Disease Case Among Military Trainees

We describe the public health response to a military trainee who developed serogroup B meningococcal disease while sharing underwater breathing equipment. Despite high transmission risk, with rapid isolation and post-exposure prophylaxis administration, there were no secondary cases. This case supports carefully weighing serogroup B meningococcal vaccination in high risk settings.

Human B Cell Responses to Dominant and Subdominant Antigens Induced by a Meningococcal Outer Membrane Vesicle Vaccine in a Phase I Trial

Neisseria meningitidis outer membrane vesicle (OMV) vaccines are safe and provide strain-specific protection against invasive meningococcal disease (IMD) primarily by inducing serum bactericidal antibodies against the outer membrane proteins (OMP). To design broader coverage vaccines, knowledge of the immunogenicity of all the antigens contained in OMVs is needed. In a Phase I clinical trial, an investigational meningococcal OMV vaccine, MenPF1, made from a meningococcus genetically modified to constitutively express the iron-regulated FetA induced bactericidal responses to both the PorA and the FetA antigen present in the OMP. Using peripheral blood mononuclear cells collected from this trial, we analyzed the kinetics of and relationships between IgG, IgA, and IgM B cell responses against recombinant PorA and FetA, including (i) antibody-secreting cells, (ii) memory B cells, and (iii) functional antibody responses (opsonophagocytic and bactericidal activities). Following MenPF1vaccination, PorA-specific IgG secreting cell responses were detected in up to 77% of participants and FetA-specific responses in up to 36%. Memory B cell responses to the vaccine were low or absent and mainly detected in participants who had evidence of preexisting immunity (P = 0.0069). Similarly, FetA-specific antibody titers and bactericidal activity increased in participants with preexisting immunity and is consistent with the idea that immune responses are elicited to minor antigens during asymptomatic Neisseria carriage, which can be boosted by OMV vaccines.

IMPORTANCENeisseria meningitidis outer membrane vesicles (OMV) are a component of the capsular group B meningococcal vaccine 4CMenB (Bexsero) and have been shown to induce 30% efficacy against gonococcal infection. They are composed of multiple antigens and are considered an interesting delivery platform for vaccines against several bacterial diseases. However, the protective antibody response after two or three doses of OMV-based meningococcal vaccines appears short-lived. We explored the B cell response induced to a dominant and a subdominant antigen in a meningococcal OMV vaccine in a clinical trial and showed that immune responses are elicited to minor antigens. However, memory B cell responses to the OMV were low or absent and mainly detected in participants who had evidence of preexisting immunity against the antigens. Failure to induce a strong B cell response may be linked with the low persistence of protective responses.

Randomized Trial of 2 Schedules of Meningococcal B Vaccine in Adolescents and Young Adults, Canada1

Emergency vaccination programs often are needed to control outbreaks of meningococcal disease caused by Neisseria meningitidis serogroup B (MenB) on college campuses. Such campaigns expend multiple campus and public health resources. We conducted a randomized, controlled, multicenter, observer-blinded trial comparing immunogenicity and tolerability of an accelerated vaccine schedule of 0 and 21 days to a longer interval of 0 and 60 days for 4-component MenB vaccine (MenB-4C) in students 17-25 years of age. At day 21 after the first MenB-4C dose, we observed protective human serum bactericidal titers >4 to MenB strains 5/99, H44/76, and NZ 98/254 in 98%-100% of participants. Geometric mean titers increased >22-fold over baseline. At day 180, >95% of participants sustained protective titers regardless of their vaccine schedule. The most common adverse event was injection site pain. An accelerated MenB-4C immunization schedule could be considered for rapid control of campus outbreaks.

Multicomponent meningococcal serogroup B vaccination elicits cross-reactive immunity in infants against genetically diverse serogroup C, W and Y invasive disease isolates

BACKGROUND

The multicomponent meningococcal serogroup B vaccine (4CMenB) is currently indicated for active immunization against invasive meningococcal disease caused by Neisseria meningitidis serogroup B (MenB). However, genes encoding the 4CMenB antigens are also variably present and expressed in strains belonging to other meningococcal serogroups. In this study, we evaluated the ability of antibodies raised by 4CMenB immunisation to induce complement-mediated bactericidal killing of non-MenB strains.

METHODS

A total of 227 invasive non-MenB disease isolates were collected between 1 July 2007 and 30 June 2008 from England and Wales, France, and Germany; 41 isolates were collected during 2012 from Brazil. The isolates were subjected to genotypic analyses. A subset of 147 isolates (MenC, MenW and MenY) representative of the meningococcal genetic diversity of the total sample were tested in the human complement serum bactericidal antibody assay (hSBA) using sera from infants immunised with 4CMenB.

RESULTS

Serogroup and clonal complex repertoires of non-MenB isolates were different for each country. For the European panel, MenC, MenW and MenY isolates belonged mainly to ST-11, ST-22 and ST-23 complexes, respectively. For the Brazilian panel, most MenC and MenW isolates belonged to the ST-103 and ST-11 complexes, respectively, and most MenY isolates were not assigned to clonal complexes. Of the 147 non-MenB isolates, 109 were killed in hSBA, resulting in an overall coverage of 74%.

CONCLUSION

This is the first study in which 147 non-MenB serogroup isolates have been analysed in hSBA to evaluate the potential of a MenB vaccine to cover strains belonging to other serogroups. These data demonstrate that antibodies raised by 4CMenB are able to induce bactericidal killing of 109 non-MenB isolates, representative of non-MenB genetic and geographic diversity. These findings support previous evidence that 4CMenB immunisation can provide cross-protection against non-MenB strains in infants, which represents an added benefit of 4CMenB vaccination.

The effect of a single 4CMenB vaccine booster in young people more than ten years after infant immunisation: protocol of an exploratory immunogenicity study

Background and rationale

The four-component capsular group B meningococcal vaccine (4CMenB) was introduced into the national immunisation schedule in the UK in September 2015 for infants in a 2 + 1 schedule at two, four and 12 months of age. A two-dose immunisation schedule for adolescents was also considered but was not found to be cost-effective in view of the relatively low rates of disease in this age group. Uncertainty about the longevity of protection induced by the vaccine and lack of certainty about an anamnestic response in primed individuals contributed to this decision.

Methods/Design

This study is an open-label, descriptive immunogenicity analysis. Up to 113 participants will be recruited, including up to 83 children who are now aged 11 years and took part in previous trials involving the administration of 4CMenB to infants, plus a group of 30 naïve age-matched controls. All previously immunised participants will receive one booster dose of 4CMenB. The 30 naïve participants will be randomised to receive two doses of 4CMenB either at 0 and 28 days or 0 and 365 days. Blood samples will be collected from all participants at 0, 28, 180 and 365 days. The primary endpoint will explore immunogenicity at day 0 and 180 in previously immunised and naïve participants. Secondary outcomes will include investigating the persistence of antibody protection in previously immunised participants at the beginning of the study, describing the characteristics of the memory B-cell responses in previously immunised participants, and measuring reactogenicity in all participants following 4CMenB doses.

Discussion

This study aims to describe whether or not a single booster dose of 4CMenB given to those who have received an infant course of 4CMenB induces a recall immune response, while concurrently describing immune responses in naïve children of the same age. If an anamnestic response is proven, a single dose adolescent booster could be envisaged as an addition to the current UK vaccination schedule.

Trial registration

EudraCT, 2017–004732-11. ISRCTN, ISRCTN16774163. Registered on 10 May 2018 (retrospectively registered).

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3494-1) contains supplementary material, which is available to authorized users.

Antibody persistence and booster response in adolescents and young adults 4 and 7.5 years after immunization with 4CMenB vaccine

BACKGROUND

Data on duration of protection against invasive meningococcal disease post-vaccination with the recombinant, 4-component, meningococcal serogroup B vaccine (4CMenB) are limited. We evaluated bactericidal activity persistence in adolescents/young adults up to 7.5 years post-primary vaccination with 4CMenB, and response to a booster dose compared with vaccine-naïve controls.

METHODS

This open-label, multicenter study (NCT02446743) enrolled 15-24 year-old-previously vaccinated participants from Canada, Australia (group Primed_4y) 4 years post-priming with 4CMenB (2 doses; 0,1-month schedule), and Chile (Primed_7.5y) 7.5 years after priming with 4CMenB (2 doses; 0,1/0,2/0,6-month schedule) and vaccine-naïve participants of similar age (Naïve_4y and Naïve_7.5y groups). Primed participants received a booster dose; vaccine-naïve participants received 2 catch-up doses of 4CMenB, 1 month apart. We evaluated antibody persistence and immune responses using hSBA in terms of geometric mean titers and percentages of participants with hSBA titers ≥4, the kinetics of bactericidal activity post-booster (previously vaccinated) or post-2 doses (vaccine-naïve), and safety.

RESULTS

Antibody levels declined at 4 (Primed_4y) and 7.5 (Primed_7.5y) years post-primary vaccination, but remained higher than in vaccine-naïve participants at baseline (≤44% vs ≤ 13% [fHbp]; ≤84% vs ≤ 24% [NadA]; ≤29% vs ≤ 14% [PorA]) for all vaccine antigens except NHBA (≤81% vs ≤ 79%). One month post-booster and post-second dose, 93-100% of primed and 79-100% of vaccine-naïve participants had hSBA titers ≥4 for all antigens. Kinetics of the antibody response were similar across groups with an early robust response observed 7 days post-booster/second dose. No vaccine-related serious adverse event was reported.

CONCLUSION

For all antigens except NHBA, a higher proportion of primed participants had hSBA titers ≥4, at 4 and 7.5 years post-vaccination, compared with vaccine-naïve participants. A more robust immune response after booster compared to a first dose in vaccine-naïve individuals, showed effective priming in an adolescent/young adult population. No safety or new reactogenicity issues were identified.

Immune Responses to Booster Vaccination With Meningococcal ABCWY Vaccine After Primary Vaccination With Either Investigational or Licensed Vaccines: A Phase 2 Randomized Study

BACKGROUND

Current meningococcal prime-boost vaccination schedules include separate vaccines for serogroups ACWY and B. An investigational combined serogroups ABCWY vaccine (MenABCWY) was developed to protect against clinically important Neisseria meningitidis serogroups.

METHODS

In this phase 2, randomized, observer-blind, extension study (NCT01272180), participants 10-25 years of age received 1 booster dose of MenABCWY vaccine at 24 months (M) postprimary series of MenABCWY (2 doses), 4CMenB (2 doses) or MenACWY-CRM vaccine (1 dose). Immune responses to booster dose (1M postbooster) and antibody persistence (24M, 36M postprimary series) were assessed using bactericidal assay with human complement (hSBA). Reactogenicity and safety were evaluated.

RESULTS

One hundred ninety participants were vaccinated. At 1M after the MenABCWY booster dose, seroresponse rates against serogroups ACWY ranged between 85% and 96%, 73% and 100% and 83% and 95% for participants previously receiving MenABCWY, 4CMenB and MenACWY-CRM, respectively. At 12M postbooster dose, ≥67% of participants across all groups had hSBA titers ≥8 for serogroups ACWY, except in 4CMenB-primed individuals for serogroup Y (45%). Across MenABCWY and 4CMenB-primed groups, hSBA titers ≥5 across serogroup B test strains were observed in 82%-100% and 29%-100% of participants at 1M and 12M postbooster, respectively. Geometric mean titers against serogroups ACWY increased from pre- to 1M postboosting with MenABCWY and persisted at 12M. The reactogenicity and safety profile of MenABCWY was similar to that of 4CMenB.

CONCLUSIONS

MenABCWY may be suitable for prime-boost schedules against meningococcal disease, including regimens involving a primary series of either 4CMenB or MenACWY-CRM licensed vaccines.

Global epidemiology of serogroup B meningococcal disease and opportunities for prevention with novel recombinant protein vaccines

BACKGROUND

Meningococcal disease (MD) is a major cause of meningitis and sepsis worldwide, with a high case fatality rate and frequent sequelae. Neisseria meningitidis serogroups A, B, C, W, X and Y are responsible for most of these life-threatening infections, and its unpredictable epidemiology can cause outbreaks in communities, with significant health, social and economic impact. Currently, serogroup B is the main cause of MD in Europe and North America and one of the most prevalent serogroups in Latin America. Mass vaccination strategies using polysaccharide vaccines have been deployed since the 1970s and the use of conjugate vaccines has controlled endemic and epidemic disease caused by serogroups A, C, W and Y and more recently serogroup B using geographically-specific outer membrane vesicle based vaccines. Two novel protein-based vaccines are a significant addition to our armamentarium against N. meningitidis as they provide broad coverage against highly diverse strains in serogroup B and other groups. Early safety, effectiveness and impact data of these vaccines are encouraging. These novel serogroup B vaccines should be actively considered for individuals at increased risk of disease and to control serogroup B outbreaks occurring in institutions or specific regions, as they are likely to save lives and prevent severe sequelae. Incorporation into national programs will require thorough country-specific analysis.

Protecting UK adolescents and adults against meningococcal serogroup B disease

INTRODUCTION

Meningococcal serogroup B disease (MenB) is endemic in the UK and continues to cause the majority of invasive meningococcal disease. Two broadly protective protein-based MenB vaccines are now licensed and available, both with wide age indications. Whilst the UK recently became the first country to routinely vaccinate infants against MenB, a recommendation has not yet been extended to older age groups who can also now benefit from these vaccines.

AREAS COVERED

This review summarizes the evidence supporting the rationale for adolescents and adults in the UK to consider MenB vaccination.

EXPERT COMMENTARY

Although MenB disease is rare, the UK reports one of the highest annual incidence rates within the European region, with over a third of cases occurring in those aged 10+ years. Overall, the case fatality rate following MenB disease in the UK is 4.2% but can be more than twice as high in teenagers and adults than in infants, and survivors are often left with life-changing disabling sequelae. MenB outbreaks are unpredictable and continue to occur in regions where it is endemic. These outbreaks often affect students attending school or university, with living on a campus being an important risk factor. Concerned individuals in this age group should consider MenB vaccination.

Invasive Meningococcal Disease on the Workplaces: a systematic review

Background and aims of the work: Invasive Meningococcal Disease (IMD) represents a global health threat, and occupational settings have the potential to contribute to its spreading. Therefore, here we present the available evidences on the epidemiology of IMD on the workplaces.

METHODS

The following key words were used to explore PubMed: Neisseria meningitidis, meningococcus, meningococcal, invasive meningococcal disease, epidemiology, outbreaks, profession(al), occupation(al).

RESULTS

We identified a total of 12 IMD cases among healthcare workers (HCW), 44 involving biological laboratory workers (BLW), 8 among school personnel, and eventually 27 from other settings, including 3 large industrial working populations. Eventual prognosis of BLW, particularly the case/fatality ratio, was dismal. As clustered in time and space, data about school cases as well as industrial cases seem to reflect community rather than occupational outbreaks. In general, we identified a common pattern for HCW and BLW, i.e. the exposure to droplets or aerosol containing N meningitidis in absence of appropriate personal protective equipment (PPE) and/or microbiological safety devices (MSD) (e.g. cabinets). Post-exposure chemoprophylaxis (PEC) was rarely reported by HCW (16.7%) workers, and never by BLW. Data regarding vaccination status were available only for a case, who had failed requested boosters.

CONCLUSIONS

The risk for occupational transmission of IMD appears relatively low, possibly as a consequence of significant reporting bias, with the exception of HCW and BLW. Improved preventive measures should be implemented in these occupational groups, in order to improve the strict use of PPE and MSD, and the appropriate implementation of PEC.

Serogroup B Meningococcus Outbreaks, Prevalence, and the Case for Standard Vaccination

PURPOSE OF REVIEW

This review explores the history of serogroup B meningitis outbreaks in American universities and the rise of the monovalent serogroup B meningococcus vaccines (MenB).

RECENT FINDINGS

Serogroup B meningitis represents 30% of American meningococcal infections and had no commercially available vaccine in the USA until 2013 when the FDA made an expanded allowance for importation of the MenB-4C vaccine for outbreaks at two American universities. Infections of Neisseria meningitidis, notably meningococcal meningitis represent a continued, lethal threat to the pediatric and adolescent populations and those with primary or acquired complement component deficiencies, largely mitigated by the quadrivalent meningococcal conjugated vaccine against serogroups A, C, W, and Y (MenACWY).

The next chapter for group B meningococcal vaccines

The majority of invasive meningococcal disease (IMD) in the developed world is caused by capsular group B Neisseria meningitidis, however success with vaccination against organisms bearing this capsule has previously been restricted to control of geographically limited clonal outbreaks. As we enter a new era, with the first routine program underway to control endemic group B meningococcal disease for infants in the UK, it is timely to review the key landmarks in group B vaccine development, and discuss the issues determining whether control of endemic group B disease will be achieved. Evidence of a reduction in carriage acquisition of invasive group B meningococcal strains, after vaccination among adolescents, is imperative if routine immunization is to drive population control of disease beyond those who are vaccinated (i.e. through herd immunity). The need for multiple doses to generate a sufficiently protective response and reactogenicity remain significant problems with the new generation of vaccines. Despite these limitations, early data from the UK indicate that new group B meningococcal vaccines have the potential to have a major impact on meningococcal disease, and to provide new insight into how we might do better in the future.

Multicomponent meningococcal B vaccination (4CMenB) of adolescents and college students in the United States

Meningococcal disease is rare, easily misdiagnosed, and potentially deadly. Diagnosis in the early stages is difficult and the disease often progresses extremely rapidly. In North America, the incidence of invasive meningococcal disease (IMD) is highest in infants and young children, with a secondary peak in adolescents, a population predominantly responsible for the carriage of disease. Neisseria meningitidis serogroup B (MenB) accounts for a large proportion of meningococcal disease in North America, with documented outbreaks in three universities in the United States (US) during 2008-2013. Vaccination is the most effective way to protect against this aggressive disease that has a narrow timeframe for diagnosis and treatment. 4CMenB is a multi-component vaccine against MenB which contains four antigenic components. We describe in detail the immunogenicity and safety profile of 4CMenB based on results from four clinical trials; the use of 4CMenB to control MenB outbreaks involving vaccination at two US colleges during outbreaks in 2013-2014; and the use of 4CMenB in a Canadian mass vaccination campaign to control the spread of MenB disease. We discuss the reasons why adolescents should be vaccinated against MenB, by examining both the peak in disease incidence and carriage. We consider whether herd protection may be attained for MenB, by discussing published models and comparing with meningitis C (MenC) vaccines. In conclusion, MenB vaccines are now available in the US for people aged 10-25 years, representing an important opportunity to reduce the incidence of IMD in the country across the whole population, and more locally to combat MenB outbreaks.

Immunogenicity of a Meningococcal B Vaccine during a University Outbreak

BACKROUND

In December 2013, a multicomponent meningococcal serogroup B (4CMenB) vaccine was used before licensure on the basis of special consideration by the Food and Drug Administration to respond to an outbreak of Neisseria meningitidis B at a U.S. university. Data suggested that vaccination would control the outbreak because isolates expressed antigens that were closely related to the vaccine antigens (factor H-binding protein [fHbp] and neisserial heparin-binding antigen). We quantified the immune responses induced by 4CMenB during the outbreak.

METHODS

We conducted a seroprevalence survey among students to assess vaccination status and collect serum specimens to quantify titers of serum bactericidal antibodies (SBA) with an assay that included human complement (hSBA). We compared the proportion of vaccinated and unvaccinated participants who were seropositive for the outbreak strain and for one closely related reference strain (44/76-SL, which included fHbp) and one mismatched reference strain (5/99, which included neisserial adhesin A), both of which were used in vaccine development. Seropositivity was defined as an hSBA titer of 4 or higher.

RESULTS

Among the 499 participants who received two doses of the 4CMenB vaccine 10 weeks apart, 66.1% (95% confidence interval [CI], 61.8 to 70.3) were seropositive for the outbreak strain, although the geometric mean titer was low at 7.6 (95% CI, 6.7 to 8.5). Among a random subgroup of 61 vaccinees who also received two doses but did not have a detectable protective response to the outbreak strain, 86.9% (95% CI, 75.8 to 94.2) were seropositive for the 44/76-SL strain, for which there was a geometric mean titer of 17.4 (95% CI, 13.0 to 23.2), whereas 100% of these vaccinees (95% CI, 94.1 to 100) were seropositive for the 5/99 strain and had a higher geometric mean titer (256.3; 95% CI, 187.3 to 350.7). The response to the outbreak strain was moderately correlated with the response to the 44/76-SL strain (Pearson's correlation,0.64; P<0.001) but not with the response to the 5/99 strain (Pearson's correlation,-0.06; P=0.43).

CONCLUSIONS

Eight weeks after the second dose of the 4CMenB vaccine was administered, there was no evidence of an hSBA response against the outbreak strain in 33.9% of vaccinees, although no cases of meningococcal disease caused by N. meningitidis B were reported among vaccinated students. (Funded by Princeton University and others.).

Meningococcal B vaccination: real-world experience and future perspectives

Invasive meningococcal disease (IMD) represents a severe risk for health. It can be considered the most dangerous vaccine-preventable disease due to the high probability of related permanent sequelae and death. The introduction in many countries of the conjugate vaccines against A, C, W135, and Y meningococcal serogroups influenced significantly the impact of the disease. Recently, the difficulties in obtaining an effective vaccine against meningococcal serogroup B (MenB) have been get over through the reverse vaccinology, enabling the recognition of some antigens providing a response against most of circulating MenB strains worldwide. The new 4cMenB vaccine is recommended in Europe, Canada, Australia, the USA, and some Latin American countries. Even if sound data on efficacy and safety profile are available, the results in terms of effectiveness are still limited. The management of the MenB outbreaks in two US universities demonstrated the ability to quickly achieve high vaccination coverage rates and no new cases among immunized subjects were assessed. It is desirable that the opportunity to complete preventive intervention against IMD offered by the new 4cMenB vaccine should be recognized and that this vaccine is included in the vaccination schedule to complete the panel of immunization against Neisseria meningitidis.

Vaccinating Italian infants with a new multicomponent vaccine (Bexsero®) against meningococcal B disease: A cost-effectiveness analysis

The European Medicines Agency has approved a multicomponent serogroup B meningococcal vaccine (Bexsero®) for use in individuals of 2 months of age and older. A cost-effectiveness analysis (CEA) from the societal and Italian National Health Service perspectives was performed in order to evaluate the impact of vaccinating Italian infants less than 1 y of age with Bexsero®, as opposed to non-vaccination. The analysis was carried out by means of Excel Version 2011 and the TreeAge Pro® software Version 2012. Two basal scenarios that differed in terms of disease incidence (official and estimated data to correct for underreporting) were considered. In the basal scenarios, we considered a primary vaccination cycle with 4 doses (at 2, 4, 6 and 12 months of age) and 1 booster dose at the age of 11 y, the societal perspective and no cost for death. Sensitivity analyses were carried out in which crucial variables were changed over probable ranges. In Italy, on the basis of official data on disease incidence, vaccination with Bexsero® could prevent 82.97 cases and 5.61 deaths in each birth cohort, while these figures proved to be three times higher on considering the estimated incidence. The results of the CEA showed that the Incremental Cost Effectiveness Ratio (ICER) per QALY was €109,762 in the basal scenario if official data on disease incidence are considered and €26,599 if estimated data are considered. The tornado diagram indicated that the most influential factor on ICER was the incidence of disease. The probability of sequelae, the cost of the vaccine and vaccine effectiveness also had an impact. Our results suggest that vaccinating infants in Italy with Bexsero® has the ability to significantly reduce meningococcal disease and, if the probable underestimation of disease incidence is considered, routine vaccination is advisable.