COMMITTEE ON INFECTIOUS DISEASES. Recommendations for Serogroup B Meningococcal Vaccine for Persons 10 Years and Older

Enhancing effect of chitosan nanoparticles on the immune efficacy of Bordetella bronchiseptica outer membrane vesicles

The outer membrane vesicle (OMV) of bacteria is a bilayer membrane vesicle with a diameter of about 10-300 nm that is secreted during the growth of Gram-negative bacteria. OMV is considered as a high-quality vaccine candidate antigen because of its natural immunogenicity and non-replicability. Although the excellent antigenicity of OMV has been widely confirmed, its instability and heterogeneity greatly affect its immune effect. Many studies have demonstrated that in combination with nanoparticles can enhance the stability of OMV. In this study, OMVs were used to coat chitosan nanoparticles (CNPs) and obtain a stable OMV vaccine. The characteristics, including morphology, hydrodynamic size, and zeta potential were evaluated. The immune protection of CNP-OMV and anti-infection efficacy were examined and compared in vivo and in vitro. The results showed that the CNP-OMV were homogenous with a size of 139 nm and a stable core-shell structure. And CNP-OMV could significantly increase the cell proliferation, phagocytosis and TNF-α, IL-6 and IL-10 secretion of RAW264.7 in vitro. In vivo, CNP-OMV could significantly increase the levels of anti-Bb and OMV IgG antibodies. Levels of blood lymphocyte, and Th1 (IFN-γ, IL-12), Th2 (IL-4, IL-5), and Th17 (IL-17, TNF-α) type cytokines in the serum were all significantly increased. At the same time, CNP-OMV could significantly reduce the bacterial invading the lungs of challenged rabbits. And CNP-OMV could largely protect the lungs from injury. The above results showed that CNP-OMV had a good immune efficacy and could resist the infection of Bordetella bronchiseptica. This study provided a scientific basis for the development of novel effective and safe vaccine against Bordetella bronchiseptica, and also provided a new idea for the development of new bacterial vaccine.

Microbe-host interactions: structure and functions of Gram-negative bacterial membrane vesicles

Bacteria-host interaction is a common, relevant, and intriguing biological phenomena. The host reacts actively or passively to the bacteria themselves, their products, debris, and so on, through various defense systems containing the immune system, the bacteria communicate with the local or distal tissues of the host via their own surface antigens, secreted products, nucleic acids, etc., resulting in relationships of attack and defense, adaptation, symbiosis, and even collaboration. The significance of bacterial membrane vesicles (MVs) as a powerful vehicle for the crosstalk mechanism between the two is growing. In the recent decade, the emergence of MVs in microbial interactions and a variety of bacterial infections, with multiple adhesions to host tissues, cell invasion and evasion of host defense mechanisms, have brought MVs to the forefront of bacterial pathogenesis research. Whereas MVs are a complex combination of molecules not yet fully understood, research into its effects, targeting and pathogenic components will advance its understanding and utilization. This review will summarize structural, extraction and penetration information on several classes of MVs and emphasize the role of MVs in transport and immune response activation. Finally, the potential of MVs as a therapeutic method will be highlighted, as will future research prospects.

Investigating the Role of Antigen Orientation on the Immune Response Elicited by Neisseria meningitidis Factor H Binding Protein on GMMA

GMMA are outer membrane vesicles (OMVs) released from Gram-negative bacteria genetically modified to enhance OMVs formation that have been shown to be optimal systems to enhance immunogenicity of protein antigens. Here, we selected Neisseria meningitidis factor H binding protein (fHbp) and used the conjugation chemistry as a tool to alter antigen orientation on GMMA. Indeed, fHbp was randomly linked to GMMA or selectively attached via the N-terminus to mimic native presentation of the protein on the bacterial surface. Interestingly, protein and peptide array analyses confirmed that antibodies induced by the selective and the random conjugates showed a pattern very similar to fHbp natively expressed on bacterial surfaces or to the recombinant protein mixed with GMMA, respectively. However, the two conjugates elicited antibodies with similar serum bactericidal activity against meningococcal strains, superior to the protein alone or physically mixed with GMMA. Presentation of fHbp on GMMA strongly enhances the functional immune response elicited by the protein but its orientation on the bacterial surface does not have an impact. This study demonstrates the flexibility of the GMMA platform as a display and delivery system for enhancing antigen immunogenicity and further supports the use of such promising technology for the development of effective vaccines.

Inclusion of a dual signal sequence enhances the immunogenicity of a novel viral vectored vaccine against the capsular group B meningococcus

BACKGROUND

Disease caused by the capsular group B meningococcus (MenB) is the leading cause of infectious death in UK infants. A novel adenovirus-based vaccine encoding the MenB factor H binding protein (fHbp) with an N-terminal dual signal sequence induces high titres of protective antibody after a single dose in mice. A panel of N-terminal signal sequence variants were created to assess the contribution of components of this sequence to transgene expression kinetics of the encoded antigen from mammalian cells and the resultant effect on immunogenicity of fHbp.

RESULTS

The full-length signal sequence (FL SS) resulted in superior early antigen expression compared with the panel of variants, as measured by flow cytometry and confocal imaging, and supported higher bactericidal antibody levels against the expressed antigen in mouse sera < 6 weeks post-immunisation than the licensed four component MenB vaccine. The FL SS also significantly increased antigen-specific T cell responses against other adenovirus-encoded bacterial antigens in mice.

CONCLUSIONS

These findings demonstrate that the FL SS enhances immunogenicity of the encoded antigen, supporting its inclusion in other viral vectored bacterial antigen transgenes.

Meningococcal Vaccination:

Neisseria meningitidis is an aerobic, gram-negative, diplococcus bacterium that is a leading cause of meningitis and sepsis in the United States. Particularly at-risk groups include those with complement deficiencies, people using complement inhibitors, individuals with anatomic or functional asplenia, patients with HIV infection and travelers to endemic countries. There are currently three quadrivalent meningococcal vaccines (Serogroups A, C, W, Y) and two recombinant serogroup B vaccines available for use in the United States, and recommendations for vaccine use have changed rapidly in the past 10-15 years. This article summarizes updated ACIP recommendations for meningococcal vaccination for the primary care provider.

Factors Associated With Receipt of Meningococcal B Vaccine Among United States Adolescents, National Immunization Survey-Teen, 2017-2018

PURPOSE

In this study, we evaluated factors associated with receipt of meningococcal serogroup B (MenB) vaccine among adolescents in the United States.

METHODS

We used public use data files from the National Immunization Survey-Teen from 2017 to 2018. Logistic regression was used to model associations among sociodemographic, healthcare, and vaccination variables of interest and MenB vaccine receipt (≥1 vs. 0 dose). To explore associations between state-level meningococcal vaccination requirements and MenB vaccine uptake, we performed a secondary analysis stratified by presence of a quadrivalent meningococcal (MenACWY) vaccination requirement for secondary school attendance in the adolescent's state of residence (no requirement vs. a one- or two-dose requirement).

RESULTS

Among 7,288 adolescents, MenB vaccine receipt was significantly associated with up-to-date human papillomavirus (adjusted odds ratio [aOR] 1.74, 95% confidence interval [CI] 1.29-2.35) and MenACWY (aOR 5.81, 95% CI 4.14-8.13) vaccination status in multivariable analysis. Adolescents with private insurance were less likely to be vaccinated (aOR .61, 95% CI .46-.79) compared to adolescents with other health insurance types. In secondary analyses, health insurance was no longer significantly associated with MenB vaccine uptake among adolescents in states with a MenACWY requirement.

CONCLUSIONS

We found that MenB vaccination is associated with receipt of other vaccines recommended for use in adolescents. Adolescents with private health insurance were less likely to be vaccinated against MenB, although state MenACWY requirements appeared to modify the effect of insurance on MenB vaccine receipt. Further work to understand how these factors may influence delivery and acceptance of MenB vaccine can inform interventions and strategies to improve uptake.

A clinical update on vaccines: focus on determinants of under-immunization and special considerations for adolescents

PURPOSE OF REVIEW

The current article reviews recent literature related to pediatric and adolescent vaccination, specifically focusing on social determinants of under-immunization, expanding adolescent immunization rates, and new recommendations surrounding the meningococcal serotype B vaccine (MenB).

RECENT FINDINGS

Vaccine refusals and vaccine-preventable diseases have been rising in some parts of the world, and appear to be linked to household factors, such as a family's socioeconomic status. Adolescents have lower immunization rates than younger children. Newer vaccines targeted at adolescents, such as the MenB vaccine, have yet to be widely accepted by pediatric providers, parents, and patients.

SUMMARY

Pediatric healthcare providers should attempt to increase local immunization rates by vaccinating children at all eligible office visits and utilizing electronic health record decision-support tools. Although the number of families who choose not to vaccinate their children may be rising, providers can be innovative (e.g. incorporate digital vaccine reminder systems) and increase their familiarity with new vaccine recommendations to continue to prevent serious vaccine-preventable diseases.

A review of the immunogenicity, safety and current recommendations for the meningococcal serogroup B vaccine, MenB-FHbp

WHAT IS KNOWN AND OBJECTIVE

This review describes invasive meningococcal disease (IMD) epidemiology in the United States, provides a brief overview of available meningococcal vaccines and discusses meningococcal serogroup B (MenB) vaccine development. Particular focus is given to the recombinant protein MenB vaccine, MenB-FHbp (Trumenba^® , bivalent rLP2086) in light of recent publication of phase 3 data; the other MenB vaccine (Bexsero^® , MenB-4C) has been recently reviewed. Current recommendations of the US Advisory Committee on Immunization Practices (ACIP) for MenB vaccination and potential barriers to immunization are also discussed.

METHODS

Using the published literature, this article reviews the development and use of MenB-FHbp to date, with a focus on the United States.

RESULTS AND DISCUSSION

Despite the availability of medical treatment, IMD is associated with significant mortality and frequently occurring serious permanent sequelae in surviving individuals. Worldwide, most IMD is caused by six serogroups (A, B, C, W, X and Y). MenB is the most common disease-causing meningococcal serogroup in the United States and has caused several recent university-based IMD outbreaks. MenB vaccines, including MenB-FHbp, are available in the United States. ACIP recommends that all individuals ≥10 years of age at increased risk for meningococcal disease receive MenB vaccination; healthy individuals 16-23 years of age are recommended MenB vaccines based on individual clinical decision-making. MenB-FHbp is used on a 2-dose schedule (0, 6 months) when vaccinating healthy individuals and on a tailored 3-dose schedule (0, 1-2, 6 months) in cases of increased risk.

WHAT IS NEW AND CONCLUSION

Because vaccination provides the most effective protection against IMD, pharmacists are in an excellent position to offer evidence-based vaccine information, as well as to encourage and provide meningococcal immunizations to adolescents and young adults.

Adverse events following immunisation with four-component meningococcal serogroup B vaccine (4CMenB): interaction with co-administration of routine infant vaccines and risk of recurrence in European randomised controlled trials

OBJECTIVES

(1) To assess if co-administration of four-component meningococcal serogroup B vaccine (4CMenB) and other routine vaccines caused an interaction increasing the risk and/or severity of adverse events following immunisation (AEFI) compared with administration at separate visits and (2) to estimate the risk of AEFI recurrence.

DESIGN

Risk-interval design SETTING: Three randomised controlled trials conducted in Europe.

PARTICIPANTS

A total of 5026 healthy 2-month-old to 15-month-old infants.

INTERVENTIONS

4CMenB and routine vaccines (hexavalent combined diphtheria-tetanus-acellular pertussis-inactivated polio-Haemophilus influenzae type b-hepatitis B vaccine+seven-valent pneumococcal conjugate vaccine or measles-mumps-rubella-varicella vaccine) administered concomitantly or separately 1 month apart, in regular (2, 4, 6 and 12 months), accelerated (2, 3, 4 and 12 months) or delayed (two doses of 4CMenB at ≥12 months of age) schedules.

OUTCOME MEASURES

Primary: Fever (≥38°C) during the first 48 hours post immunisation. Secondary: crying, change in eating habits, diarrhoea, irritability and tenderness at the 4CMenB injection site.

RESULTS

Compared with separate administration, concomitant administration decreased the overall incidence of fever (≥38°C), 86% versus 75%, and other systemic AEFIs but increased the incidence of 4CMenB injection site tenderness, 55% versus 66%, moderate/severe fevers (≥39°C), 13% versus 18%, and long-lasting (>1 day) fevers, 23% versus 33%. Co-administration reduced AEFI risk by 4%-49% with the greatest impact among infants with prior AEFI(s). Fever recurrence risk was proportional to the number of prior fever events: 79% at dose 2 with one prior episode; 44% and 74% at dose 3 with one and two prior episodes, respectively; and 29%, 45% and 60% at dose 4 with one, two and three prior episodes, respectively. Severity was not increased at recurrence and a similar pattern of recurrence risk proportional to the number of prior events was observed for other AEFIs.

CONCLUSIONS

The cumulative risk of AEFI is reduced with concomitant versus separate administration of 4CMenB and routine infant vaccines. Infants with a prior AEFI are at higher risk of the same AEFI at subsequent immunisations, but severity with recurrence is usually not increased.

TRIALS REGISTRATION NUMBER

NCT00657709, NCT00847145, NCT00721396 and NCT02712177; Pre-results.

Vaccinations in pediatric kidney transplant recipients

Pediatric kidney transplant (KT) candidates should be fully immunized according to routine childhood schedules using age-appropriate guidelines. Unfortunately, vaccination rates in KT candidates remain suboptimal. With the exception of influenza vaccine, vaccination after transplantation should be delayed 3-6 months to maximize immunogenicity. While most vaccinations in the KT recipient are administered by primary care physicians, there are specific schedule alterations in the cases of influenza, hepatitis B, pneumococcal, and meningococcal vaccinations; consequently, these vaccines are usually administered by transplant physicians. This article will focus on those deviations from the normal vaccine schedule important in the care of pediatric KT recipients. The article will also review human papillomavirus vaccine due to its special importance in cancer prevention. Live vaccines are generally contraindicated in KT recipients. However, we present a brief review of live vaccines in organ transplant recipients, as there is evidence that certain live virus vaccines may be safe and effective in select groups. Lastly, we review vaccination of pediatric KT recipients prior to international travel.

Parental awareness of Meningococcal B vaccines and willingness to vaccinate their teens

Background:

In the US, Meningococcal B (MenB) vaccines were first licensed in 2014. In 2015, the Advisory Committee on Immunization Practices recommended that parents of teens talk to their provider about receiving MenB vaccine, rather than issuing a routine recommendation. We assessed parental awareness of MenB vaccines and willingness to vaccinate their teens with MenB vaccines compared to MenACWY vaccines, which have been routinely recommended for many years.

Methods:

We surveyed parents of teens attending high school in 2017–18 during the Minnesota State Fair. Parents reported via iPad their knowledge of and concern about meningococcal disease and their awareness of and willingness to vaccinate with MenB and MenACWY vaccines. We assessed the relationship between meningococcal disease knowledge and concern, MenB and MenACWY vaccine awareness, and willingness to vaccinate with MenB and MenACWY using adjusted logistic regression.

Results:

Among 445 parents, the majority had not heard of the newly introduced MenB vaccines Bexsero^® (80.0%; 95% CI: 76.0–83.6) or Trumenba^® (82.0%; 95% CI: 78.1–85.5) or the MenACWY vaccines Menactra^® or Menveo^® (68.8%; 95% CI: 64.2–73.0). The majority were at least somewhat willing to vaccinate their teen with MenB vaccine (89.6%; 95% CI: 86.5, 92.3) and MenACWY vaccine (91.2%; 95% CI: 88.2, 93.7). Awareness of MenB vaccines (OR: 3.8; 95% CI: 1.2–12.2) and concern about meningococcal disease (OR: 3.1; 95% CI: 1.5–6.3) were significantly associated with willingness to vaccinate with MenB vaccine.

Conclusions:

Awareness of MenB vaccine is lacking among parents of teens but is an important predictor of willingness to vaccinate with the newly licensed MenB vaccines.

Adoption of Serogroup B Meningococcal Vaccine Recommendations

: media-1vid110.1542/5799875076001PEDS-VA_2018-0344Video Abstract BACKGROUND AND OBJECTIVES: In 2015, the Advisory Committee on Immunization Practices recommended that 16- to 23-year-olds may be vaccinated with the serogroup B meningococcal (MenB) vaccine on the basis of individual clinical decision-making (Category B). We assessed the following among US pediatricians and family physicians (FPs): (1) practices regarding MenB vaccine delivery, (2) factors influencing a decision to recommend the MenB vaccine, and (3) factors associated with discussing the MenB vaccine.

METHODS

We surveyed a nationally representative sample of pediatricians and FPs via e-mail and Internet from October 2016 to December 2016.

RESULTS

The response rate was 72% (660 of 916). During routine visits, 51% of pediatricians and 31% of FPs reported always or often discussing MenB vaccine. Among those who discussed often or always, 91% recommended vaccination; among those who never or rarely discussed, 11% recommended. We found that 73% of pediatricians and 41% of FPs currently administered the MenB vaccine. Although many providers reported not knowing about factors influencing recommendation decisions, MenB disease outbreaks (89%), disease incidence (62%), and effectiveness (52%), safety (48%), and duration of protection of MenB vaccine (39%) increased the likelihood of recommendation, whereas the Category B recommendation (45%) decreased likelihood. Those somewhat or not at all aware of the MenB vaccine (risk ratio 0.32 [95% confidence interval 0.25-0.41]) and those practicing in a health maintenance organization (0.39 [0.18-0.87]) were less likely, whereas those aware of disease outbreaks in their state (1.25 [1.08-1.45]) were more likely to discuss MenB vaccine.

CONCLUSIONS

Primary care physicians have significant gaps in knowledge about MenB disease and the MenB vaccine, and this appears to be a major driver of the decision not to discuss the vaccines.

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.

Knowledge and Attitudes Regarding Category B ACIP Recommendations Among Primary Care Providers for Children

OBJECTIVE

In 2015, the Advisory Committee on Immunization Practices (ACIP) made a category B recommendation for use of serogroup B meningococcal (MenB) vaccines, meaning individual clinical decision-making should guide recommendations. This was the first use of a category B recommendation pertaining to a large population and the first such recommendation for adolescents. As part of a survey regarding MenB vaccine, our objectives were to assess among pediatricians (Peds) and family physicians (FPs) nationally: 1) knowledge of the meaning of category A versus B recommendations and insurance coverage implications, and 2) attitudes about category A and B recommendations.

METHODS

We surveyed a nationally representative sample of Peds and FPs via e-mail and mail from October to December 2016.

RESULTS

The response rate was 72% (660 of 916). Although >80% correctly identified the definition of a category A recommendation, only 24% were correct about the definition for category B. Fifty-five percent did not know that private insurance would pay for vaccines recommended as category B, and 51% did not know that category B-recommended vaccines would be covered by the Vaccines for Children program. Fifty-nine percent found it difficult to explain category B recommendations to patients; 22% thought ACIP should not make category B recommendations; and 39% were in favor of category B recommendations because they provide leeway in decision-making.

CONCLUSIONS

For category B recommendations to be useful in guiding practice, primary care clinicians will need to have a better understanding of their meaning, their implications for insurance payment, and guidance on how to discuss them with parents and patients.

The 2016 Lifetime Immunization Schedule, approved by the Italian scientific societies: A new paradigm to promote vaccination at all ages

Medical scientific societies have the core mission of producing, pooling and disseminating solid and updated scientific information. We report the successful experience of the partnership of four national Medical Scientific Societies active in Italy in producing scientific advice on vaccines and vaccination. In particular, i) the Italian Society of Hygiene, Preventive Medicine and Public Health; SitI, ii) the Italian Society of Paediatrics; SIP, iii) the "Italian Federation of General Practitioners"; FIMP, and iv) the Italian Federation of General Medicine FIMMG) have worked together since 2012 to produce shared evidence-based recommendations on vaccination schedules, namely the "Lifetime Immunization Schedule" which introduced for the first time in Italy a life-course approach to vaccination. The 2014 edition of the "Lifetime Immunization Schedule" was used as a basis to develop the 2017-2019 Italian National Prevention Plan, approved by The Italian Ministry of Health in February 2017. In this report, we present the structure, content and supporting evidence of the new 2016 "Lifetime Immunization Schedule" and we expand on the influential role of medical scientific societies in researching and advocating for effective and safe vaccination programmes' implementation at the national level.

Emerging clinical experience with vaccines against group B meningococcal disease

The prevention of paediatric bacterial meningitis and septicaemia has recently entered a new era with the availability of two vaccines against capsular group B meningococcus (MenB). Both of these vaccines are based on sub-capsular proteins of the meningococcus, an approach that overcomes the challenges set by the poorly immunogenic MenB polysaccharide capsule but adds complexity to predicting and measuring the impact of their use. This review describes the development and use of MenB vaccines to date, from the use of outer membrane vesicle (OMV) vaccines in MenB outbreaks around the world, to emerging evidence on the effectiveness of the newly available vaccines. While recent data from the United Kingdom supports the potential for protein-based vaccines to provide direct protection against MenB disease in immunised children, further research is required to understand the breadth and duration of this protection. A more detailed understanding of the impact of immunisation with these vaccines on nasopharyngeal carriage of the meningococcus is also required, to inform both their potential to induce herd immunity and to preferentially select for carriage of strains not susceptible to vaccine-induced antibodies. Although a full understanding of the potential impact of these vaccines will only be possible with this additional information, the availability of new tools to prevent the devastating effect of invasive MenB disease is a significant breakthrough in the fight against childhood sepsis and meningitis.

Contribution of factor H-Binding protein sequence to the cross-reactivity of meningococcal native outer membrane vesicle vaccines with over-expressed fHbp variant group 1

Factor H-binding protein (fHbp) is an important meningococcal vaccine antigen. Native outer membrane vesicles with over-expressed fHbp (NOMV OE fHbp) have been shown to induce antibodies with broader functional activity than recombinant fHbp (rfHbp). Improved understanding of this broad coverage would facilitate rational vaccine design. We performed a pair-wise analysis of 48 surface-exposed amino acids involved in interacting with factor H, among 383 fHbp variant group 1 sequences. We generated isogenic NOMV-producing meningococcal strains from an African serogroup W isolate, each over-expressing one of four fHbp variant group 1 sequences (ID 1, 5, 9, or 74), including those most common among invasive African meningococcal isolates. Mice were immunised with each NOMV, and sera tested for IgG levels against each of the rfHbp ID and for ability to kill a panel of heterologous meningococcal isolates. At the fH-binding site, ID pairs differed by a maximum of 13 (27%) amino acids. ID 9 shared an amino acid sequence common to 83 ID types. The selected ID types differed by up to 6 amino acids, in the fH-binding site. All NOMV and rfHbp induced high IgG levels against each rfHbp. Serum killing from mice immunised with rfHbp was generally less efficient and more restricted compared to NOMV, which induced antibodies that killed most meningococci tested, with decreased stringency for ID type differences. Breadth of killing was mostly due to anti-fHbp antibodies, with some restriction according to ID type sequence differences. Nevertheless, under our experimental conditions, no relationship between antibody cross-reactivity and variation fH-binding site sequence was identified. NOMV over-expressing different fHbp IDs belonging to variant group 1 induce antibodies with fine specificities against fHbp, and ability to kill broadly meningococci expressing heterologous fHbp IDs. The work reinforces that meningococcal NOMV with OE fHbp is a promising vaccine strategy, and provides a basis for rational selection of antigen sequence types for over-expression on NOMV.

The Need to Optimize Adolescent Immunization

The adolescent period heralds the pediatric patient's transition into adulthood. It is a time of dynamic development during which effective preventive care measures can promote safe behaviors and the development of lifelong health habits. One of the foundations of preventive adolescent health care is timely vaccination, and every visit can be viewed as an opportunity to update and complete an adolescent's immunizations.In the past decade, the adolescent immunization schedule has expanded to include 2 doses of quadrivalent meningococcal conjugate vaccine, 1 dose of tetanus, diphtheria, acellular pertussis, absorbed vaccine, 2 or 3 doses of human papillomavirus vaccine, depending on the child's age, and an annual influenza vaccine. In addition, during adolescent visits, health care providers can determine whether catch-up vaccination is needed to meet early childhood recommendations for hepatitis B; hepatitis A; measles, mumps, rubella; poliovirus; and varicella vaccines. New serogroup B meningococcal vaccines are now available for those at increased risk for meningococcal disease; in addition, these serogroup B meningococcal vaccines received a Category B recommendation for healthy adolescents, where individual counseling and risk-benefit evaluation based on health care provider judgements and patient preferences are indicated. This clinical report focuses on the epidemiology of adolescent vaccine-preventable diseases by reviewing the rationale for the annual universally recommended adolescent immunization schedule of the American Academy of Pediatrics, the American Academy of Family Physicians, the Centers for Disease Control and Prevention, and the American Congress of Obstetricians and Gynecologists. In addition, the barriers that negatively influence adherence to this current adolescent immunization schedule will be highlighted.