Invasive meningococcal disease epidemiology and control measures: a framework for evaluation

Meningococcal Disease Outbreaks: A Moving Target and a Case for Routine Preventative Vaccination

Outbreaks of invasive meningococcal disease (IMD) are unpredictable, can be sudden and have devastating consequences. We conducted a non-systematic review of the literature in PubMed (1997-2020) to assess outbreak response strategies and the impact of vaccine interventions. Since 1997, IMD outbreaks due to serogroups A, B, C, W, Y and X have occurred globally. Reactive emergency mass vaccination campaigns have encompassed single institutions (schools, universities) through to whole sections of the population at regional/national levels (e.g. serogroup B outbreaks in Saguenay-Lac-Saint-Jean region, Canada and New Zealand). Emergency vaccination responses to IMD outbreaks consistently incurred substantial costs (expenditure on vaccine supplies, personnel costs and interruption of other programmes). Impediments included the limited pace of transmission of information to parents/communities/healthcare workers; issues around collection of informed consents; poor vaccine uptake by older adolescents/young adults, often a target age group; issues of reimbursement, particularly in the USA; and difficulties in swift supply of large quantities of vaccines. For serogroup B outbreaks, the need for two doses was a significant issue that contributed substantially to costs, delayed onset of protection and non-compliance with dose 2. Real-world descriptions of outbreak control strategies and the associated challenges systematically show that reactive outbreak management is administratively, logistically and financially costly, and that its impact can be difficult to measure. In view of the unpredictability, fast pace and potential lethality of outbreak-associated IMD, prevention through routine vaccination appears the most effective mitigation tool. Highly effective vaccines covering five of six disease-causing serogroups are available. Preparedness through routine vaccination programmes will enhance the speed and effectiveness of outbreak responses, should they be needed (ready access to vaccines and need for a single booster dose rather than a primary series).

Mesquita S, Jimenez L, Avila AA, Sutter CJ, Sutter R. Vaccine-related attitudes and decision-making among uninsured, Latin American immigrant mothers of adolescent daughters: a qualitative study

Uninsured Latin American immigrant women are at increased risk for vaccine preventable diseases, such as cervical cancer; yet gaps in vaccine coverage persist. The purpose of this study was to explore vaccine-related knowledge, attitudes and decision-making for tetanus, diphtheria, and acellular pertussis (Tdap) vaccine, meningococcal conjugate vaccine (MenACWY), and human papillomavirus (HPV) vaccine among uninsured Latin American immigrant mothers of adolescent daughters. A purposive sample of 30 low-income, uninsured, predominantly Latin-American immigrant mothers of adolescent daughters aged 13-17 were recruited from two academic-community managed health clinics in Virginia. From March-September 2016, data were collected through in-person, semi-structured interviews, in English or Spanish. For data analysis, conventional content analysis was employed. The majority of participants self-identified as Hispanic and had less than a high-school level education. Key themes included: general acceptance of vaccines; associating vaccines with prevention/protection; minimal vaccine hesitancy; and lack of knowledge regarding vaccine-preventable diseases, vaccines recommended for adolescents, and adolescent daughters' vaccination history. Doctors' recommendation, school requirements, and the media were key influencers of vaccination. Mothers were the primary decision-maker regarding vaccine uptake among their adolescent daughters. Findings highlight the need for efforts to help uninsured Latin American immigrant mothers better understand vaccines, and provide linkages to affordable, accessible vaccines among under-resourced populations.

Cost-effectiveness of alternate strategies for childhood immunization against meningococcal disease with monovalent and quadrivalent conjugate vaccines in Canada

BACKGROUND

Public health programs to prevent invasive meningococcal disease (IMD) with monovalent serogroup C meningococcal conjugate vaccine (MCV-C) and quadrivalent meningococcal conjugate vaccines (MCV-4) in infancy and adolescence vary across Canadian provinces. This study evaluated the cost-effectiveness of various vaccination strategies against IMD using current and anticipated future pricing and recent epidemiology.

METHODS

A cohort model was developed to estimate the clinical burden and costs (CAN$2014) of IMD in the Canadian population over a 100-year time horizon for three strategies: (1) MCV-C in infants and adolescents (MCV-C/C); (2) MCV-C in infants and MCV-4 in adolescents (MCV-C/4); and (3) MCV-4 in infants (2 doses) and adolescents (MCV-4/4). The source for IMD incidence was Canadian surveillance data. The effectiveness of MCV-C was based on published literature. The effectiveness of MCV-4 against all vaccination regimens was assumed to be the same as for MCV-C regimens against serogroup C. Herd effects were estimated by calibration to estimates reported in prior analyses. Costs were from published sources. Vaccines prices were projected to decline over time reflecting historical procurement trends.

RESULTS

Over the modeling horizon there are a projected 11,438 IMD cases and 1,195 IMD deaths with MCV-C/C; expected total costs are $597.5 million. MCV-C/4 is projected to reduce cases of IMD by 1,826 (16%) and IMD deaths by 161 (13%). Vaccination costs are increased by $32 million but direct and indirect IMD costs are projected to be reduced by $46 million. MCV-C/4 is therefore dominant vs. MCV-C/C in the base case. Cost-effectiveness of MCV-4/4 was $111,286 per QALY gained versus MCV-C/4 (2575/206 IMD cases/deaths prevented; incremental costs $68 million).

CONCLUSIONS

If historical trends in Canadian vaccines prices continue, use of MCV-4 instead of MCV-C in adolescents may be cost-effective. From an economic perspective, switching to MCV-4 as the adolescent booster should be considered.

The impact of aggregating serogroups in dynamic models of Neisseria meningitidis transmission

Background

Neisseria meningitidis (Nm) is a pathogen of multiple serogroups that is highly prevalent in many populations. Serogroups associated with invasive meningococcal disease (IMD) in Canada, for example, include A, B, C, W-135, X and Y. IMD is a rare but serious outcome of Nm infection, and can be prevented with vaccines that target certain serogroups. This has stimulated the development of dynamic models to evaluate vaccine impact. However, these models typically aggregate the various Nm serogroups into a small number of combined groups, instead of modelling each serogroup individually. The impact of aggregation on dynamic Nm model predictions is poorly understood. Our objective was to explore the impact of aggregation on dynamic model predictions.

Methods

We developed two age-structured agent-based models--a 2-strain model and a 4-strain model--to simulate vaccination programs in the Canadian setting. The 2-strain model was used to explore two different groupings: C, versus all other serogroups combined; and B, versus all other serogroups combined. The 4-strain model used the four groupings: C, B, Neisseria lactamica, versus all other serogroups combined. We compared the predicted impact of monovalent C vaccine, quadrivalent ACWY vaccine (MCV-4), and monovalent B vaccine (4CMenB) on the prevalence of serogroup carriage under these different models.

Results

The 2-strain and 4-strain models predicted similar overall impacts of vaccines on carriage prevalence, especially with respect to the vaccine-targeted serogroups. However, there were some significant quantitative and qualitative differences. Declines in vaccine-targeted serogroups were more rapid in the 2-strain model than the 4-strain model, for both the C and the 4CMenB vaccines. Sustained oscillations, and evidence for multiple attractors (i.e., different types of dynamics for the same model parameters but different initial conditions), occurred in the 4-strain model but not the 2-strain model. Strain replacement was also more pronounced in the 4-strain model, on account of the 4-strain model spreading prevalence more thinly across groups and thus enhancing competitive interactions.

Conclusions

Simplifying assumptions like aggregation of serogroups can have significant impacts on dynamic model predictions. Modellers should carefully weigh the advantages and disadvantages of aggregation when formulating models for multi-strain pathogens.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1015-8) contains supplementary material, which is available to authorized users.

Public health management of invasive meningococcal disease in Baden-Wuerttemberg, Germany, 2012: adherence to guidance and estimation of resources required as determined in a survey of local health authorities

Background

Invasive meningococcal disease (IMD) incidence in Germany is low, but management of contacts to prevent subsequent cases still requires resources. Local public health authorities (LHA) advise antibiotic post-exposure prophylaxis (PEP) and vaccination to close contacts as defined in national guidance. We aimed to audit implementation of recommendations for IMD public health management in the state of Baden-Wuerttemberg, Germany, and to estimate associated costs.

Methods

We surveyed all 38 LHAs in Baden-Wuerttemberg to evaluate knowledge of national guidance and implementation of IMD contact management using standardized questionnaires. For IMD cases notified in 2012, we requested numbers of household and other contacts ascertained, including advice given regarding PEP and post-exposure vaccination, plus staff time required for their management. We estimated costs for advised antibiotics, LHA staff time and visits to emergency departments according to published sources. The cost of preventing a subsequent case was estimated based on the number of household contacts that received PEP per IMD case and on the previous finding that ~284 household contacts must receive PEP to prevent one subsequent IMD case.

Results

Although LHAs were familiar with national recommendations, they did not advise PEP to 4% of household contacts, while 72% and 100% of school and health provider contacts, respectively, were advised PEP. Only 25% of household contacts of a case with a vaccine-preventable serogroup were advised post-exposure vaccination. A mean of 11.0 contacts/IMD case (range 0–51), of which 3.6 were household contacts, were recommended PEP. Per IMD case, mean costs for LHA staff were estimated at €440.86, for antibiotics at €219.14 and for emergency department visits to obtain PEP at €161.70 - a total of €821.17/IMD case. Preventing a subsequent IMD case would cost ~ €65,000.

Conclusions

Our results provide insight into costs of IMD public health management in Germany. We identified marked underuse of post-exposure vaccination in household contacts and overuse of PEP in school and health care contacts. In view of an estimated 3–6 quality-adjusted life years lost per case of IMD, our estimated cost of €65,000 for preventing a subsequent case seems justifiable.

Relationships Between Clinico-Epidemiological Patterns of Invasive Meningococcal Infections and Complement Deficiencies in French South Pacific Islands (New Caledonia)

PURPOSE

Invasive Meningococcal Disease (IMD) is three fold more common in New Caledonia (NC) than in metropolitan France and many IMD cases (35.7%) are due to Y and W135 serogroups. The purpose of our study was to identify IMD risk factors in NC.

METHODS

A retrospective study of all IMD cases that occurred in NC between 2005 and 2011 was conducted. Socio-environmental, clinical and biological data were collected. A search for immune deficiency was proposed to all cases. IMD presentation and outcome were compared according to meningoccal serogroups and the complement deficiency status (C-deficiency).

RESULTS

Sixty-six sporadic IMD cases (29 B serogroup, 20 Y or W135, 6 C, 1 A, 10 unknown) occurred in 64 patients often <24 years-old and of Melanesian origin. Five patients died (7.8%). No socio-environmental risk factors were identified. No asplenia, HIV infection or immunoglobulin deficiencies were found. Two patients had diabetes and 28 of 53 (52.8%) patients had C-deficiency including 20 (71.4%) cases of late complement component deficiency. Patients with C-deficiency were mainly Melanesian (92.8%) originating from the Loyalty Islands (62.1%). They were mostly infected with Y/W135 (42.9%) or B serogroups (32.1%). They often developed later and more severe disease than patients without C-deficiency (need for intensive cares in 60% versus 28.0% of cases, p = 0.01).

CONCLUSIONS

A high prevalence of C-deficiency in the Melanesian population may explain epidemiological and clinical features of IMD in NC. Our results imply an adaptation of meningococcal vaccine strategies in NC.

Development, theoretical framework, and evaluation of a parent and teacher-delivered intervention on adolescent vaccination

The Advisory Committee on Immunization Practices recommended immunization schedule for adolescents includes three vaccines (tetanus, diphtheria, and acellular pertussis [Tdap]; human papillomavirus [HPV] vaccine; and meningococcal conjugate vaccine [MCV4]) and an annual influenza vaccination. Given the increasing number of recommended vaccines for adolescents and health and economic costs associated with nonvaccination, it is imperative that effective strategies for increasing vaccination rates among adolescents are developed. This article describes the development, theoretical framework, and initial first-year evaluation of an intervention designed to promote vaccine acceptance among a middle and high school-based sample of adolescents and their parents in eastern Georgia. Adolescents, parents, and teachers were active participants in the development of the intervention. The intervention, which consisted of a brochure for parents and a teacher-delivered curriculum for adolescents, was guided by constructs from the health belief model and theory of reasoned action. Evaluation results indicated that our intervention development methods were successful in creating a brochure that met cultural relevance and the literacy needs of parents. We also demonstrated an increase in student knowledge of and positive attitudes toward vaccines. To our knowledge, this study is the first to extensively engage middle and high school students, parents, and teachers in the design and implementation of key theory-based educational components of a school-based, teacher-delivered adolescent vaccination intervention.

Persistence of immunity following a booster dose of Haemophilus influenzae type B-Meningococcal serogroup C glycoconjugate vaccine: follow-up of a randomized controlled trial

BACKGROUND

Antibodies against Haemophilus influenzae type b (Hib) and serogroup C Neisseria meningitidis (MenC) wane after early infant immunization.

METHODS

Children previously immunized in a randomized controlled trial at ages 2, 3, and 4 months with DTPa-IPV-Hib and MenC-CRM197 (MenC-CRM group) or DTPa-IPV and Hib-MenC-TT (Hib-MenC-TT group) had blood samples drawn at 1 and 2 years following a booster dose of Hib-MenC-TT at 12 to 15 months of age. A blood sample was also drawn at the year 2 follow-up from a separately recruited age-matched control group who had not received a booster.

RESULTS

In 271 children at year 1, mean 14.6 months (range: 12-18 months) following the Hib-MenC-TT booster, MenC bactericidal titers above the protective threshold (rSBA ≥ 1:8) was demonstrated in 89.0% of the Hib-MenC-TT group and 69.5% of MenC-CRM participants. Antipolyribosylribitol phosphate Ig ≥ 1.0 μg/mL (Hib correlate for long-term protection) was seen in 94.9% and 82.5%, respectively.In 379 participants (including 72 control children) at year 2 (age: 39-43 months, 25-31 months post Hib-MenC-TT) persistence of MenC antibodies was demonstrated in 67.1% of the Hib-MenC-TT group and 40.5% of the MenC-CRM group, compared with 44.1% of control group participants. Antipolyribosylribitol phosphate Ig ≥ 1.0 μg/mL was seen in 89.0%, 74.7%, and 38.9%, respectively.

CONCLUSIONS

A toddler Hib-MenC-TT booster helps sustain immunity against Hib to 3½ years of age. Persistence of MenC antibody is similar in children primed with MenC-CRM197 in infancy who receive a booster Hib-MenC-TT, to those who receive no booster. Persistence of MenC antibody is better when primed and boosted with Hib-MenC-TT.

Methodological concerns with economic evaluations of meningococcal vaccines

The evolution of meningococcal vaccines illustrates nicely the incremental technological process that is common to much medical innovation and particularly appropriate to economic analysis. However, the economic evaluation of vaccines is complicated by several features unique to vaccines, including the possibility of indirect (herd immunity) benefits and the shear breadth of vaccination strategies available to decision makers. As with the vaccines themselves, the modelling approaches applied to the economic evaluation of meningococcal vaccines have evolved to become increasingly complex. Despite such innovation, concerns remain about the quality of economic studies of meningococcal vaccines. This article reviews evaluations of meningococcal vaccine strategies in developed countries and provides recommendations for future work in this area. Four potentially problematic areas in the existing literature are identified - indirect costs, herd immunity, quality of life and comparison programmes - and approaches to these issues are discussed. Recommendations for reporting a 'minimum analysis profile' case are also made. Although comparisons across studies are difficult at best, recent work shows that incorporating the indirect benefits and costs of vaccination substantially improves cost effectiveness.

Vaccine adherence in adolescents

Although a number of routine and catch-up vaccinations are currently recommended for adolescents, coverage rates of these vaccines are currently suboptimal. Routine recommended immunizations for this cohort include vaccines for influenza, human papillomavirus, and meningococcal disease, as well as a booster for tetanus, diphtheria, and acellular pertussis. Adolescence is also a critical period for administration of catch-up vaccines for those not fully immunized during childhood. Adolescents who do not seek appropriate preventive healthcare are at risk for significant morbidity and possible mortality. Increasing adolescent adherence to recommended vaccine schedules presents a challenge and opportunity for pediatricians and public health advocates. This article outlines barriers to vaccine compliance among adolescents and discusses strategies to increase vaccine uptake.

Neisseria meningitidis: epidemiology, treatment and prevention in adolescents

PURPOSE OF REVIEW

Neisseria meningitidis has been recognized as a cause of serious disease for centuries, but changing epidemiology and advances in treatment and prevention strategies mandate that providers be aware of ongoing developments with regard to this infection. Given the high burden of disease in adolescents, it is important for clinicians to be familiar with current recommendations regarding N. meningitidis.

RECENT FINDINGS

Adolescents and young adults continue to have the second highest incidence of disease from N. meningitidis. New diagnostic techniques, including polymerase chain reaction, have shown promise for enhancing detection of meningococcal infection in selected scenarios. Whereas most isolates of meningococcus remain penicillin-susceptible, fluoroquinolone resistance has now been documented in the US for the first time. Routine immunization using the meningococcal conjugate vaccine continues to be recommended, despite ongoing concern about a possible association between vaccination and Guillain-Barré syndrome. Active research is ongoing to develop a serogroup B vaccine and meningococcal vaccines that are immunogenic in infants and toddlers.

SUMMARY

Given the increased incidence of meningococcal infection among adolescents and the substantial morbidity and mortality associated with invasive disease, adolescent health providers must be familiar with current antibiotic treatment and prophylaxis guidelines and ongoing developments regarding meningococcal vaccination.

Herd immunity: recent uses in vaccine assessment

Human communities defend themselves against specific infectious agents in a way that extends beyond the simple sum of the immune status of its individuals. By analogy with individual immunity to specific agents, the community level of immunity may vary from complete susceptibility to full protection. Herd immunity has been used to name this community property, which is the result of evolution through natural selection, leading to relationships between two species, typical of prey-predator systems. Varying uses of the term herd immunity led to the use of other expressions, such as herd protection, herd effect and community immunity. Knowledge derived from observational studies and models on herd immunity has supported decisions on the choice of vaccines and vaccination strategies for the benefit of populations. This knowledge is most likely to be extended in the future, with far-reaching effects.