Half a Century of Wilson & Jungner: Reflections on the Governance of Population Screening

Background: In their landmark report on the "Principles and Practice of Screening for Disease" (1968), Wilson and Jungner noted that the practice of screening is just as important for securing beneficial outcomes and avoiding harms as the formulation of principles. Many jurisdictions have since established various kinds of "screening governance organizations" to provide oversight of screening practice. Yet to date there has been relatively little reflection on the nature and organization of screening governance itself, or on how different governance arrangements affect the way screening is implemented and perceived and the balance of benefits and harms it delivers. Methods: An international expert policy workshop convened by Sturdy, Miller and Hogarth. Results: While effective governance is essential to promote beneficial screening practices and avoid attendant harms, screening governance organizations face enduring challenges. These challenges are social and ethical as much as technical. Evidence-based adjudication of the benefits and harms of population screening must take account of factors that inform the production and interpretation of evidence, including the divergent professional, financial and personal commitments of stakeholders. Similarly, when planning and overseeing organized screening programs, screening governance organizations must persuade or compel multiple stakeholders to work together to a common end. Screening governance organizations in different jurisdictions vary widely in how they are constituted, how they relate to other interested organizations and actors, and what powers and authority they wield. Yet we know little about how these differences affect the way screening is implemented, and with what consequences. Conclusions: Systematic research into how screening governance is organized in different jurisdictions would facilitate policy learning to address enduring challenges. Even without such research, informal exchange and sharing of experiences between screening governance organizations can deliver invaluable insights into the social as well as the technical aspects of governance.

Half a Century of Wilson & Jungner: Reflections on the Governance of Population Screening

Background: In their landmark report on the “Principles and Practice of Screening for Disease” (1968), Wilson and Jungner noted that the practice of screening is just as important for securing beneficial outcomes and avoiding harms as the formulation of principles. Many jurisdictions have since established various kinds of “screening governance organizations” to provide oversight of screening practice. Yet to date there has been relatively little reflection on the nature and organization of screening governance itself, or on how different governance arrangements affect the way screening is implemented and perceived and the balance of benefits and harms it delivers. Methods: An international expert policy workshop convened by the three lead authors. Results: While effective governance is essential to promote beneficial screening practices and avoid attendant harms, screening governance organizations face enduring challenges. These challenges are social and ethical as much as technical. Evidence-based adjudication of the benefits and harms of population screening must take account of factors that inform the production and interpretation of evidence, including the divergent professional, financial and personal commitments of stakeholders. Similarly, when planning and overseeing organized screening programs, screening governance organizations must persuade or compel multiple stakeholders to work together to a common end. Screening governance organizations in different jurisdictions vary widely in how they are constituted, how they relate to other interested organizations and actors, and what powers and authority they wield. Yet we know little about how these differences affect the way screening is implemented, and with what consequences. Conclusions: Systematic research into how screening governance is organized in different jurisdictions would facilitate policy learning to address enduring challenges. Even without such research, informal exchange and sharing of experiences between screening governance organizations can deliver invaluable insights into the social as well as the technical aspects of governance.

The combined impact of implementing HPV immunisation and primary HPV screening in New Zealand: Transitional and long-term benefits, costs and resource utilisation implications

BACKGROUND

In response to emergent evidence, many countries are transitioning from cytology-based to HPV screening. We evaluated the impact of an upcoming transition on health outcomes and resource utilisation in New Zealand.

METHODS

An extensively validated model of HPV transmission, vaccination, natural history and cervical screening ('Policy1-Cervix') was utilised to simulate a transition from three-yearly cytology for women 20-69 years to five-yearly HPV screening with 16/18 genotyping for women 25-69 years, accounting for population growth and the impact of HPV immunisation. Cervical cancer rates, resources use (test volumes), costs, and test positivity rates from 2015 to 2035 were estimated.

FINDINGS

By 2035, the transition to HPV screening will result in declines in cervical cancer incidence and mortality rates by 32% and 25%, respectively, compared to 2018. A potentially detectable 5% increase in cervical cancer incidence due to earlier detection is predicted for the year of transition. Annual numbers of women screened will fluctuate with the five-year screening interval. Cytology volumes will reduce by over 80% but colposcopy volumes will be similar to pre-transition rates, and program costs will be reduced by 16%. A 9% HPV test positivity rate is expected in the first round of HPV screening (2019-2023), with 2.7% of women referred for colposcopy. Transitioning from cytology to primary HPV cervical screening could avert 149 cancer cases and 45 deaths by 2035.

CONCLUSION

Primary HPV screening and vaccination will reduce cervical cancer and resources use. A small transient apparent increase of invasive cancer rates due to earlier detection may be detectable at the population level, reflecting the introduction of a more sensitive screening test. These findings can be used to inform health services planning and public communications surrounding program implementation.

Post-Marketing Safety Monitoring of a New Group B Meningococcal Vaccine in New Zealand, 2004-2006

New Zealand introduced a new outer membrane vesicle vaccine in 2004 to combat an epidemic of group B meningococcal disease. An Independent Safety Monitoring Board oversaw intensive safety monitoring, which included hospital surveillance, health professional reporting (passive and active) and mortality monitoring. With over three million doses administered to individuals aged under 20 years, the monitoring results provide consistent evidence supporting the vaccine's safety.

Vaccines against meningococcal serogroup B disease containing outer membrane vesicles (OMV): lessons from past programs and implications for the future

The utility of wild-type outer membrane vesicle (wtOMV) vaccines against serogroup B (MenB) meningococcal disease has been explored since the 1970s. Public health interventions in Cuba, Norway and New Zealand have demonstrated that these protein-based vaccines can prevent MenB disease. Data from large clinical studies and retrospective statistical analyses in New Zealand give effectiveness estimates of at least 70%. A consistent pattern of moderately reactogenic and safe vaccines has been seen with the use of approximately 60 million doses of three different wtOMV vaccine formulations. The key limitation of conventional wtOMV vaccines is their lack of broad protective activity against the large diversity of MenB strains circulating globally. The public health intervention in New Zealand (between 2004–2008) when MeNZB was used to control a clonal MenB epidemic, provided a number of new insights regarding international and public-private collaboration, vaccine safety surveillance, vaccine effectiveness estimates and communication to the public. The experience with wtOMV vaccines also provide important information for the next generation of MenB vaccines designed to give more comprehensive protection against multiple strains.

Health policy responses to rising rates of multi-morbid chronic illness in Australia and New Zealand

OBJECTIVE

To examine current health policy in Australia and New Zealand and assess the extent to which the policies equip these countries to meet the challenges associated with increasing rates of multi-morbid chronic illnesses.

METHOD

We examined reports from agencies holding data relating to chronic illness in both countries, looking at prevalence trends and the frequency of multiple morbidities being recorded. We undertook content analysis of health policy documents from Australian and New Zealand government agencies.

RESULTS

The majority of people with chronic illness have multiple morbidities. Multi-morbid chronic illnesses significantly effect the health of people in both Australia and New Zealand and place substantial demands on the health systems of those countries. These consequences are both predicted to increase dramatically in the near future. Despite this, neither country explicitly acknowledges multi-morbidity as a major factor in their policies addressing chronic illness.

CONCLUSION AND IMPLICATION

In addition to considering policy responses to chronic illness, policy makers should explicitly consider policies shaped to address the needs of people with multi-morbid chronic illness.

Properties and clinical performance of vaccines containing outer membrane vesicles from Neisseria meningitidis

Meningococcal outer membrane proteins have been used for over 20 years in more than 80 million doses; either as carrier protein in a Haemophilus influenzae type b (Hib) polysaccharide conjugate vaccine or as vesicle vaccine formulations against meningococcal disease. Conventional wild-type outer membrane vesicle (wtOMV) vaccines are the only formulations that have shown efficacy against serogroup B meningococcal disease. This has been demonstrated in Cuba, Norway and New Zealand; where epidemics, dominated by one particular strain or clone, were causing high rates of disease and wtOMV vaccines have been used for epidemic control. The most significant limitation for widespread use of wtOMV is that the immune response is strain-specific in infants, mostly directed against the immuno-dominant porin protein, PorA. The natural orientation of surface-exposed membrane antigens and the preservation of good physico-chemical stability are key features of OMV vaccines. The efficacy, tolerability and safety of wtOMV vaccines have been well proven. The most recent experience from New Zealand demonstrated a vaccine effectiveness of 80% for children less than 5 years of age, over a period of 24 months. Such results are encouraging for the further use of "tailor-made" OMV vaccines for epidemic control. Moreover, it provides opportunities for development of OMV vaccines with various additional cross-protective potential. There is good reason to believe that in the coming few years the "OMV-concept" will be exploited further and that a number of cross-protective "universal" antigens will be included in vaccines against serogroup B meningococcal disease. The desire to have a global vaccine strategy that enables susceptible individuals to be protected against all the relevant serogroups of meningococcal disease may become a reality.

Delivering a safe and effective strain-specific vaccine to control an epidemic of group B meningococcal disease

In response to a devastating group B meningococcal disease epidemic in New Zealand, a case was prepared for new health funding and a new outer membrane vesicle vaccine, MeNZB, developed. Following clinical trials demonstrating satisfactory immunogenicity and safety profiles a national implementation strategy was prepared. MeNZB was introduced halfway through the 14th year of the epidemic with a campaign targeting children and young people aged under 20 years delivered over 2 years. By its completion in June 2006, the vaccine had been delivered to more than 1 million young people. All of the above steps were achieved within 5 years. This unique endeavour was possible due to a private/public partnership between the New Zealand Ministry of Health and Chiron Vaccines. This paper summarises the outcomes of this campaign including coverage levels achieved, evidence of vaccine effectiveness and safety, and the strategies used to manage key events and risks that emerged during the campaign.

Use of an observational cohort study to estimate the effectiveness of the New Zealand group B meningococcal vaccine in children aged under 5 years

BACKGROUND

In July 2004 a strain-specific vaccine was introduced to combat an epidemic of group B meningococcal disease in New Zealand. We estimated the effectiveness of this vaccine in pre-school-aged children.

METHODS

We conducted a cohort analysis of all children in New Zealand who were aged 6 months to <5 years at the time the vaccine became available for that age group in their area. We defined cases as children who were diagnosed with laboratory-confirmed epidemic strain meningococcal disease. We calculated person-days-at-risk using data from the National Immunization Register and population estimates from Statistics New Zealand. We estimated vaccine effectiveness as 1--relative risk.

RESULTS

Compared with unvaccinated children, fully vaccinated children were five to six times less likely to contract epidemic strain meningococcal disease in the 24 months after they became eligible to receive a full vaccination series, corresponding to an estimated vaccine effectiveness of 80.0% (95% confidence interval: 52.5-91.6) for children aged 6 months to <5 years and 84.8% (95% confidence interval: 59.4-94.3) for children aged 6 months to <3 years.

CONCLUSIONS

With over 3 million doses administered to individuals aged under 20 years throughout New Zealand, combined evidence from the Phase I and II clinical trials, the descriptive epidemiology of meningococcal disease, and this study provide evidence supporting the effectiveness of this vaccine in the 2 years following vaccination.

Surveillance of vaccine breakthrough cases following MeNZB vaccination

AIM

To describe and investigate epidemic strain serogroup B meningococcal disease in recipients of the meningococcal vaccine, MeNZB.

METHOD

Epidemic strain meningococcal disease cases in vaccine recipients were identified by matching disease notification and laboratory data against the National Immunisation Register. Descriptive analyses were undertaken for disease cases aged under 20 years and vaccine breakthrough cases (epidemic strain meningococcal disease cases with onset 28 or more days after receipt of the third MeNZB dose). Questionnaires were sent to hospital clinicians requesting medical histories and laboratory test results for vaccine breakthrough cases. A committee reviewed this information to assess immune competence in these cases.

RESULTS

From the start of the meningococcal B immunisation programme in July 2004 to the end of 2006, 34 vaccine breakthrough cases were identified. No underlying host factors were identified that explained disease occurrence for the 30 cases (88.2%) for whom questionnaires were completed. For 12 (35.3%) cases all requested laboratory tests to assess immune competence were performed and these subjects were judged to be immune competent.

CONCLUSION

While epidemic strain meningococcal disease incidence has fallen dramatically with the introduction of the vaccine, these early results confirm the expectation that vaccine breakthrough cases will occur in immune competent individuals given the anticipated vaccine effectiveness of approximately 75%.

A prospective study of the effectiveness of the New Zealand meningococcal B vaccine

The effectiveness of a new group B strain-specific meningococcal vaccine referred to as "MeNZB," developed by Chiron Vaccines (Siena, Italy) in collaboration with the Norwegian Institute of Public Health, was assessed in a prospective observational study following a nationwide vaccination program in New Zealand. The vaccination program began in July 2004, and the study uses data from January 2001 to June 2006. A generalized estimating equation model was used to estimate vaccine effectiveness that included potential confounding variables, such as disease progression over time, age, ethnicity, socioeconomic status, seasonality, and geographic region. The model provides strong statistical evidence for a vaccine effect (p < 0.0001), with estimated disease rates 3.7 times higher in the unvaccinated group than in the vaccinated group (95% confidence interval: 2.1, 6.8) and a vaccine effectiveness of 73% (95% confidence interval: 52, 85). An estimated 54 epidemic strain meningococcal cases were prevented in the 2 years since the vaccination program began (95% confidence interval assuming a fixed population size: 22, 115). In a sensitivity analysis, these estimates proved to be robust to modeling assumptions, including population estimates, estimates of the numbers vaccinated, effects of partial vaccination, and temporal autocorrelation.

Immunogenicity, reactogenicity, and safety of a P1.7b,4 strain-specific serogroup B meningococcal vaccine given to preteens

New Zealand (NZ) has experienced a Neisseria meningitidis serogroup B epidemic since 1991. MeNZB, a strain-specific outer membrane vesicle vaccine made using an NZ epidemic strain isolate, NZ98/254 (B:4:P1.7b,4), from two manufacturing sites, the Norwegian Institute of Public Health (NIPH) and Chiron Vaccines (CV; now Novartis), was evaluated for safety, immunogenicity, and reactogenicity in this observer-blind trial with 8- to 12-year-old children. In year 1, cohort A (n = 302) was randomized 4:1 for receipt of NIPH-MeNZB or MenBvac (Norwegian parent vaccine strain 44/76; B:15:P1.7,16). In year 2, cohort B (n = 313) was randomized 4:1 for receipt of CV-MeNZB or NIPH-MeNZB. Participants all received three vaccinations 6 weeks apart. Local and systemic reactions were monitored for 7 days. Seroresponse was defined as a fourfold or greater rise in the serum bactericidal antibody titer from the baseline titer as measured by a serum bactericidal assay. Those with baseline titers of <1:4 required titers of >/=1:8 to serorespond. Intention-to-treat (ITT) and per protocol (PP) analyses are presented. In cohort A, 74% (ITT) and 73% (PP) of NIPH-MeNZB recipients demonstrated seroresponses against NZ98/254 after three doses, versus 32% (ITT and PP) of MenBvac recipients. In cohort B, seroresponses against NZ98/254 after three doses occurred in 79% (ITT and PP) of CV-MeNZB versus 75% (ITT) and 76% (PP) of NIPH-MeNZB recipients. Vaccines were tolerable, with no vaccine-related serious adverse events. In conclusion, the NZ strain meningococcal B vaccine (MeNZB) from either manufacturing site was immunogenic against New Zealand epidemic vaccine strain meningococci with no safety concerns when given in three doses to these 8- to 12-year-old children.

Immunogenicity and safety of a strain-specific MenB OMV vaccine delivered to under 5-year olds in New Zealand

To control the devastating group B meningococcal epidemic in New Zealand a strain-specific OMV vaccine (MeNZB) was extensively tested before vaccination of >1,000,000 people under 20 years. After the three-dose course 75% of 6-8-month-old infants and 16-24-month-old toddlers showed four-fold increases in bactericidal antibodies. In 6-10-week-old infants a fourth dose was needed to obtain similar results. After primary vaccination, the antibody titre decline was most pronounced among the youngest but both young infants and toddlers showed a clear booster response to a fourth dose. MeNZB was safe and well tolerated. The comprehensive post-licensure safety surveillance revealed no safety concerns.

New zealand epidemic strain meningococcal B outer membrane vesicle vaccine in children aged 16-24 months

BACKGROUND

New Zealand has experienced an epidemic of Neisseria meningitidis dominated by strain B:4:P1.7b,4 since 1991. Children younger than 5 years are at highest risk. Previous serogroup B outer membrane vesicle (OMV) strain specific vaccines have shown variable efficacy in this age group.

OBJECTIVE

To evaluate the immunogenicity, reactogenicity and safety in 16-24-month-old children of an OMV vaccine developed against the New Zealand epidemic strain.

METHODS

Children (332) aged 16-24 months were randomized to receive the New Zealand candidate vaccine made using strain NZ98/254 (B:4:P1.7b,4) or the Norwegian parent vaccine made using strain 44/76 (B:15:P1.7,16). Vaccines (25 microg/dose) were administered at 0, 6 and 12 weeks in this observer-blind trial. Immune response was measured by serum bactericidal assay and enzyme-linked immunosorbent assay. Sero-response was defined as a 4-fold or greater rise in serum bactericidal antibody titer compared with baseline, with titers <1:4 required to increase to >or=1:8 to be considered a sero-response. Local and systemic reactions were monitored for 7 days after vaccination.

RESULTS

Sero-response against NZ98/254 was achieved after 3 doses in 75% (95% CI: 69-80%) receiving the New Zealand candidate vaccine by both intention to treat (ITT) and per protocol (PP) analyses. In Norwegian parent vaccinees this was seen in 3% (0-12%) (ITT) and 4% (0-13%) (PP). Vaccines were well tolerated with no vaccine-related serious adverse events.

CONCLUSION

The New Zealand candidate vaccine administered to these 16-24-month-old children in 3 doses was safe and elicited a promising immune response against the candidate vaccine strain NZ98/254 (N. meningitidis B:4:P1.7b,4) contributing to vaccine licensure for this age group.

Safety review: two outer membrane vesicle (OMV) vaccines against systemic Neisseria meningitidis serogroup B disease

MenBvac is an OMV vaccine against systemic serogroup B Neisseria meningitidis disease. MenBvac was developed for control of a B:15:P1.7,16 subtype epidemic in Norway and administered to 180,000 subjects in 28 clinical studies. MeNZB, a daughter vaccine of MenBvac, was developed for a clonal B:4:P1.7b,4 epidemic in New Zealand and administered to 1 million people <20 years. The vaccines were similar regarding reactogenicity profile. Serious adverse events (SAEs) in general and particularly neurologic SAEs were very rare. Despite frequently reported local reactions and fever in those under 5 years, these OMV-based vaccines containing 25 microg antigen can be considered safe for use in all age groups.

Understanding the immune responses to the meningococcal strain-specific vaccine MeNZB measured in studies of infants

Vaccine trials with infants enrolled between 6 and 10 weeks of age (young infants) and 6 and 8 months of age (older infants) provided an opportunity to evaluate immunoglobulin G (IgG) isotype distribution and avidity maturation as indicators of antibody function and immunologic memory. Following vaccination with a strain-specific outer membrane vaccine, MeNZB, pre- and postvaccination sera were used to determine IgG isotype responses and avidity indices (AI) in subsets of vaccinated subjects. Measurements of IgG isotypes involved 100 infants from each trial. AI were measured in 50 infants from the young infant trial who received a fourth vaccine dose and in 40 older infants from whom serum was collected 7 months after the primary vaccination course. IgG1 and IgG3 dominated the responses to the vaccine. A modest linear correlation (P < 0.001) occurred between serum bactericidal antibody (SBAb) titers and the total IgG or the IgG1 antibody units in older infants. The young infants showed a modest linear correlation between SBAb and total IgG (P = 0.005) and a weak linear correlation between SBAb and IgG1 (P = 0.003). Increased avidity with age was demonstrated in both groups. The AI in the young infants increased from 51.5% (95% confidence interval [CI], 47.7 to 54.7) postvaccination to 68.7% (95% CI, 65.5 to 71.9%) following the fourth dose of vaccine (P < 0.001). The mean avidity of the older infants increased significantly (P = 0.00012) from 42.4% (95% CI, 39.1 to 45.3%) postvaccination to 50.4% (95% CI, 47.2 to 53.6%) 4 months later. A fourth dose of MeNZB is now being given to young infants at 10 months of age.

The VR2 epitope on the PorA P1.7-2,4 protein is the major target for the immune response elicited by the strain-specific group B meningococcal vaccine MeNZB

A protracted epidemic of group B meningococcal disease in New Zealand led to the testing of a strain-specific tailor-made vaccine, MeNZB. Immunogenicity levels achieved during age group trials enabled New Zealand's regulatory authority to grant licensure to deliver MeNZB to all individuals under age 20. During the trials target strains for serum bactericidal antibody measurements included the vaccine target strain NZ98/254 and two comparator epidemic-type strains (NZ94/167 and NZ02/09). In this study, 12 other strains differing variously from the vaccine strain by their capsular group, PorB type, and PorA variable region specificities, or PorA expression, were used as target strains. The PorA specificity of the serum bactericidal antibody responses to the vaccine was determined for 40 vaccinees. Sets of 10 pre- and postvaccination sera were chosen randomly from the young infant, older infant, toddler, and school-age group trials. Antibody recognition of linearized PorA proteins was also determined using immunoblotting. Across all age groups vaccine-induced serum bactericidal antibodies specifically targeted the VR2 P1.4 epitope of the PorA P1.7-2,4 protein irrespective of the PorB type and/or capsular type of the target strain. Deletion of amino acids within the VR2 epitope or replacement of the epitope through genetic exchange allowed strains variously to resist antibody-directed complement-mediated lysis and negated PorA-specific antibody recognition in immunoblots. The demonstration that the immunodominant antibody response was specifically for the VR2 P1.4 epitope of the PorA protein supports the public health decision to use a strain-specific vaccine for the control of New Zealand's epidemic of meningococcal disease.

Safety and immunogenicity of New Zealand strain meningococcal serogroup B OMV vaccine in healthy adults: Beginning of epidemic control

As the first step towards control of a strain specific epidemic of meningococcal disease in New Zealand (NZ), this study, an observer-blind, randomised controlled trial in 75 healthy adults, evaluated safety and immunogenicity of two different dosages of a meningococcal group B vaccine administered in a three dose regime. The "tailor-made" outer membrane vesicle (OMV) vaccine (candidate vaccine) developed using a New Zealand meningococcal group B strain (B:4:P1.7b,4) was well tolerated with no vaccine related serious adverse events. Similar local and systemic reactions were observed in those receiving the New Zealand candidate vaccine and the control parent Norwegian vaccine (MenBvac). A four-fold rise in serum bactericidal antibodies (SBAb) against the vaccine strain 4-6 weeks after the third vaccination was achieved in 100% of New Zealand candidate vaccine 2,519 microg participants and in 87% of 50 microg participants. The safety and immunogenicity profile observed in this study of healthy adults enabled studies in children to be initiated using 25 microg dosage.

MeNZB: a safe and highly immunogenic tailor-made vaccine against the New Zealand Neisseria meningitidis serogroup B disease epidemic strain

Clinical studies have been conducted in New Zealand evaluating the safety and immunogenicity of an outer membrane vesicle (OMV) vaccine, MeNZB, developed to control epidemic disease caused by group B meningococci, subtype P1.7b,4. MeNZB, administered in a three-dose regimen, was well tolerated and induced a seroresponse, defined as a four-fold rise (> or =titre 8) in serum bactericidal antibodies against the vaccine strain 4-6 weeks after the third vaccination, in 96% (95% confidence interval (CI): 79-100%) of adults, 76% (95% CI: 72-80%) of children, 75% (95% CI: 69-80%) of toddlers and 74% (95% CI: 67-80%) of infants receiving MeNZB. In conclusion, these findings suggest that MeNZB is safe and is likely to confer protection against systemic group B meningococcal disease caused by the epidemic strain.

Validation of the serum bactericidal assay for measurement of functional antibodies against group B meningococci associated with vaccine trials

Provisional licensure of the trial vaccine, MeNZB, required demonstration of immune responses in vaccines, as measured by a validated Serum Bactericidal Assay (SBA). Reported are the investigations undertaken to define test parameters, lower limits of quantitation and measurement of SBA reproducibility. Results helped to formulate the operating procedure for the measurement of serum bactericidal antibodies during six age-group MeNZB vaccine trials. The lower limit of quantitation was determined as a titre of 4. A four-fold rise in antibody (sero-conversion) from a pre-vaccination titre of 2 (<4) required a minimum post-vaccination titre of 8, a more stringent measurement than has been used in other published studies.

From secondary prevention to primary prevention: a unique strategy that gives hope to a country ravaged by meningococcal disease

New Zealand has been affected by an epidemic of group B meningococcal disease dominated by a strain defined as, B:4:P1.7b,4. Over 5550 cases and 222 deaths have been reported since 1991 in a population of 4 million people. Meningococcal disease cases notified on EpiServ database operated by Institute of Environmental Science and Research Limited through to 30 September 2004. Through the collaborative efforts of a government agency, vaccine company, university and laboratory institute, clinical trials of the Chiron produced outer membrane vesicle (OMV) strain-specific MeNZB vaccine were run in rapid succession. The delivery of MeNZB will be New Zealand's largest immunisation programme with three doses given at 6-week intervals to over 1 million people aged 6 weeks-19 year olds inclusive. Planning, co-ordinating and delivering the immunisation programme is a challenging project for the New Zealand Health Sector.

The strategy to control New Zealand's epidemic of group B meningococcal disease

BACKGROUND

In New Zealand today, babies of Pacific ethnicity born in South Auckland have a 1-in-48 chance of contracting meningococcal disease by the time they are 5 years of age.

METHODS

The New Zealand government, Chiron Vaccines and the University of Auckland have collaborated to develop and investigate a group B meningococcal vaccine to allow a mass-immunization program to control a prolonged and intense epidemic. Within 3 years, a strain-specific meningococcal outer membrane vesicle vaccine has been developed, and overlapping clinical trials have been undertaken; a report was submitted for regulatory approval within 2 years. An important aspect of the project's strategy was to apply, with physicochemical data, the results of the New Zealand outer membrane vesicle vaccine trials to the parent vaccine produced and evaluated by the Norwegian National Institute of Public Health. Immunogenicity results for the New Zealand vaccine are promising, with the vaccine showing a reactogenicity profile similar to that of the parent vaccine.

CONCLUSIONS

Controlling the epidemic depends on delivering an effective vaccine to the individuals at greatest risk, ie, mainly Maori and Pacific populations that previous health programs have struggled to reach. Participation of and partnership with these communities in public health decision-making and vaccine delivery will be critical to a successful immunization program.

Proceedings of the Meningococcal Vaccine Strategy World Health Organization satellite meeting, 10 March 2004, Auckland, New Zealand

From 1991 to the end of 2003 there have been 5293 cases and 216 deaths from meningococcal disease in New Zealand. On 10 March 2004, the New Zealand Ministry of Health hosted a special meeting to release the first results of the clinical trial in 16 to 24 month olds of a new vaccine (MeNZB), which has been tailor-made to provide protection against the New Zealand epidemic strain. These proceedings summarise the key points from the meeting presentations and highlight some of the important issues considered in the subsequent discussion. In the toddler age-group trial, 75% of the MeNZB recipients exhibited a four-fold or greater rise in serum bactericidal antibodies after three doses of MeNZB--compared with 4% of the control vaccine recipients. Local reactions to MeNZB and the control vaccine were common, especially injection site tenderness. These data, along with data from New Zealand clinical trials in four other age groups and efficacy and safety data from the Norwegian parent vaccine, were used to support the application for a licence to use MeNZB in a proposed mass immunisation programme for 0-19 year olds. During the immunisation programme, a comprehensive safety monitoring programme will be in place to monitor for any adverse reactions following MeNZB immunisation. This will include real-time hospital-based monitoring in the regions first to roll out the vaccine.

The New Zealand Meningococcal Vaccine Strategy: a tailor-made vaccine to combat a devastating epidemic

The New Zealand Meningococcal Vaccine Strategy aims to end the devastating 14-year epidemic of B:4:P1.7b,4 group B meningococcal disease in New Zealand through a mass immunisation programme to all under 20 year olds using a tailor-made vaccine (MeNZB). This paper describes the scientific rationale, development, and key components of the New Zealand Meningococcal Vaccine Strategy. A summary of the efficacy and safety data of existing outer membrane vesicle group B meningococcal vaccines is included as these data critically support the Strategy.

Meningococcal disease epidemiology and control in New Zealand

Epidemiology, surveillance and research New Zealand has a high quality surveillance system for meningococcal disease that successfully integrates notification and laboratory data. Since 1991, New Zealand has had elevated incidence rates of meningococcal disease rising to 6.2 per 100,000 population in 1994. This represents a rate that is four times that recorded in 1989/90. Serogroup B infection predominates and international experience suggests that these elevated rates may continue for 5 to 15 years. Rates of meningococcal disease in Maori and Pacific Islands populations were three times higher than in Europeans at 10.0 and 12.3 per 100,000 respectively in 1994. The rates were particularly high for infants with the rate in Maori infants under 1 year reaching 120 per 100,000. The case fatality rate at 5.3% for 1994 would appear to be relatively low by international standards. Case control studies could be used to investigate potentially modifiable primary risk factors for disease. Intensive case review studies to investigate the role of such factors as preadmission antibiotics in reducing severe outcomes may be of benefit. The Ministry of Health or research funding organisations should consider the potential value of such studies in more detail.