Rapid identification of herd effects with the introduction of serogroup C meningococcal conjugate vaccine in Ontario,Canada, 2000–2006

In 2001, Canada's National Advisory Committee on Immunization endorsed a meningococcal serogroup C conjugate vaccine, which appears to provide durable serogroup-specific immunity while reducing nasopharyngeal carriage. With reference to direct and indirect effects on case occurrence, we sought to evaluate recent trends in the incidence of invasive meningococcal disease (IMD) in Ontario. Analyses included all IMD cases reported between 2000 and 2006 to the Ontario Central Public Health Laboratory. Poisson models incorporating terms for age, sex and seasonal oscillation identified a significant downward trend in disease occurrence, which was strongest in serogroup C cases and not evident when serogroup C strains were excluded from the analysis. Among age groups not targeted by the vaccine program serogroup C, IMD displayed a pattern of decreasing incidence that was not present in non-serogroup C disease. These apparent dramatic effects of conjugate C vaccine (both direct and indirect) may be important in the implementation and evaluation of vaccine policy in other jurisdictions.     

Impact of vaccination during an epidemic of serogroup C meningococcal disease in Salvador, Brazil

To combat rising incidence of serogroup C meningococcal disease in the city of Salvador, Brazil, the Bahia state immunization program initiated routine childhood immunization with meningococcal C conjugate vaccine (MenC) in February 2010, followed by mass MenC vaccination of city residents 10-24 years of age from May through August 2010. We analyzed trends in incidence of reported cases of meningococcal disease and serogroup distribution among meningococcal isolates identified in hospital-based surveillance in Salvador from January 2000 to December 2011 and estimated vaccine effectiveness using the screening method. Annual incidence of serogroup C meningococcal disease increased from 0.1 cases per 100,000 population during 2000-2006 to 2.3 in 2009 and 4.1 in 2010, before falling to 2.0 per 100,000 in 2011. Estimated coverage of mass vaccination reached 80%, 67% and 41% among 10-14, 15-19 and 20-24 year olds, respectively. Incidence in 2011 was significantly lower than average rates in 2008-2009 among children <5 years, but reductions among 10-24 year olds were not significant. Among 10-24 year olds, a single dose of MenC vaccine was 100% effective (95% confidence interval, 79-100%) against serogroup C meningococcal disease. Low coverage in the population targeted for mass vaccination may have limited impact on ongoing transmission of serogroup C meningococcal disease despite high vaccine effectiveness.     

National surveillance for meningococcal disease in Japan, 1999–2014

We summarize the epidemiology of Japanese meningococcal disease with serogroup distribution. One hundred seventy-eight meningococcal meningitis cases were reported from April 1999 to March 2013 to the national surveillance system. From April 2013, bacteremia was added to the condition of reporting invasive meningococcal disease (IMD). Since then, 59 IMD cases were reported by the end of 2014. Approximately two thirds of the cases were male and the median age was 56 years (range: 0–93 years). Only 3% of the cases were <5 years old. One third of reported cases were meningitis and the others were bacteremia. The annual incidence (2014) for IMD was 0.028 per 100,000 and case fatality rate (CFR) was 19%. Serogroup Y (42%) was the most dominant serogroup, followed by C (12%), B (7%) and W (3%). Even though the number of reported cases has increased after the amendment of reporting requirements, the incidence of IMD is still low in Japan. Underreporting may play a role in this low incidence. Improving on the limitations of the surveillance system is necessary to capture the true epidemiology and accurate serogroup distribution of IMD cases in Japan, which is essential for making effective recommendations on newly licensed vaccine.     

Annual report of the Australian Meningococcal Surveillance Programme, 2005

In 2005 there were 345 laboratory-confirmed cases of invasive meningococcal disease (IMD) analysed by the National Neisseria Network, a nationwide network of reference laboratories. The phenotypes (serogroup, serotype and serosubtype) and antibiotic susceptibility of 214 isolates of Neisseria meningitidis from invasive cases of meningococcal disease were determined and an additional 131 cases were confirmed by non-culture-based methods. Nationally, 251 (73%) confirmed cases were infected with serogroup B and 50 (14.5%) with serogroup C meningococci. The total number of confirmed cases was 16 fewer than the 361 cases identified in 2004. The number of cases decreased in Queensland, Tasmania, New South Wales and the Australian Capital Territory and increased slightly in Victoria, South Australia, Western Australia and the Northern Territory. The age distribution of IMD showed a typical primary peak in those aged four years or less with a lower secondary peak in adolescents and young adults. Serogroup B cases were 90 per cent of all cases in those aged four years or less and 75 per cent in those aged 15-24 years. The proportion of all invasive disease represented by serogroup C disease was highest in the 20-24 years and older age groups. The common phenotypes circulating in Australia were B:15:P1.7 and C:2a:P1.5. However significant jurisdictional differences in the serogroup and phenotypic distribution of meningococci were again evident and considerable heterogeneity of subtypes was noted. No evidence of meningococcal capsular 'switching' or genetic recombination was detected. About two thirds of all isolates showed decreased susceptibility to the penicillin group of antibiotics (MIC 0.06-0.5 mg/L). A single isolate was penicillin resistant at 1 mg/L and another was rifampicin resistant.     

Changing epidemiology of Infant Meningococcal Disease after the introduction of meningococcal serogroup C vaccine in Italy, 2006–2014

BackgroundIn Italy, the incidence of Invasive Meningococcal Disease (IMD) was around 0.28 per 100,000 over the last years. Since the risk IMD is usually high among infants aged less than 1 year, we decided to evaluate the trend of IMD cases reported between 2006 and 2014 in this age group. In particular, the study aim was to describe the main characteristics of IMD cases in infants following the introduction of MCC vaccine (2005) and to estimate the number of cases which are potentially preventable through early vaccination.MethodsThe National Surveillance System of Bacterial Meningitis was established in 1994 and in 2007 was extended to all invasive bacterial diseases. Clinical data and isolates and/or clinical samples are collected from hospitalized patients throughout the country. IMD cases are reported by clinicians to the local health authorities, and samples are sent to the Reference Laboratory at the Istituto Superiore di Sanità for further characterization and storage at −80 °C. In particular, serogroup identification is obtained by agglutination with commercial antisera or by multiplex PCR.ResultsThe annual incidence for infants <1 year old remained rather stable of 3.6 per 100,000, with several upward and downward oscillations and a peak in 2010. The incidence of IMD among infants was more than 10 times higher than the overall rate of IMD observed in Italy. Finally, serogroup B was more frequently detected among infants aged <1 year, accounting for 65% of the total (p < 0.01).ConclusionsDuring the study period, IMD incidence reported among infants aged less than one year old was 10 times higher than the overall rate, and serogroup B was the most commonly detected over time. The long-term impact of meningococcal C conjugate vaccine and the effect of the introduction of meningococcal B vaccination among infants need to be evaluated.     

The changing and dynamic epidemiology of meningococcal disease

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

1950—2020年江苏省流行性脑脊髓膜炎流行特征及菌群变迁趋势分析

目的 分析江苏省1950—2020年流行性脑脊髓膜炎(流脑)流行发病趋势及菌群分布特征。方法 收集1950—2020年江苏省流脑病例监测数据,并对各时期流脑发病特征进行描述分析。结果 1950—2020年江苏省流脑报告病例1 067 148例,在1965年、1959年、1977年,经历了3次流行高峰,广泛使用疫苗后,流脑发病率下降明显,2006年以来,流脑发病率一直处在0.1/10万以下。2006—2010年,流脑病例C群比例为50.77%,A群为32.31%,B群为1.54%。2011—2015年,C群占33.33%,A群占20.00%,W135群占20.00%,B群占6.67%,其他及不可分群占比15.38%,2016—2020年,C群进一步减少为16.67%,A群减少至8.33%,B群比例增加至25.00%,W135群比例为16.67%,其他及不可分群上升为33.33%。结论 江苏省流脑疫情维持在低位,菌群由以C群为主,向B群为主变迁,其他及不可分群比例显著上升。流脑防控局面发生新变化。     

Annual report of the Australian Meningococcal Surveillance Programme, 2006

In 2006 there were 271 laboratory-confirmed cases of invasive meningococcal disease analysed by the National Neisseria Network, a nationwide network of reference laboratories. The phenotypes (serogroup, serotype and serosubtype) and antibiotic susceptibility of 166 isolates of Neisseria meningitidis from invasive cases of meningococcal disease were determined and an additional 105 cases were confirmed by non-culture-based methods. Nationally, 217 (80%) confirmed cases were infected with serogroup B and 26 (9.6%) with serogroup C meningococci. The total number of confirmed cases was 74 (21%) fewer than the 345 cases identified in 2005. Numbers of cases decreased in all jurisdictions except Queensland. The age group showing the greatest decrease in numbers (by about one-third) was in those aged 25 years or more. A typical primary disease peak was observed in those aged 4 years or less with a lower secondary peak in adolescents and young adults. Serogroup B cases were 93% of all cases in those aged 4 years or less and 77% in those aged 15-24 years. The proportion of invasive disease represented by serogroup C disease was highest in the 20-24 years and 25-44 years age groups. The common phenotypes circulating in Australia were B:15:P1.7, B:4:P1.4, C:2a:P1.4 and C:2a:P1.5, but again with significant jurisdictional differences. No evidence of meningococcal capsular 'switching' was detected. About two thirds of all isolates showed decreased susceptibility to the penicillin group of antibiotics (MIC 0.06-0.5 mg/L). All isolates remained susceptible to rifampicin and ciprofloxacin.     

Annual report of the Australian Meningococcal Surveillance Programme, 2009

In 2009 there were 233 laboratory-confirmed cases of invasive meningococcal disease (IMD) analysed by the National Neisseria Network, Australia, a nationwide network of reference laboratories. One hundred and thirty-five isolates of Neisseria meningitidis from invasive cases of meningococcal disease were available for which the phenotypes (serogroup, serotype and serosub-type) and/or genotype and antibiotic susceptibility were determined. An additional 98 cases were confirmed by non-culture-based methods (92 by nucleic acid amplification testing (NAAT) and six by serology) , and where possible serotyping was determined. Nationally, 194 (83%) laboratory-confirmed cases where a serogroup was determined were infected with serogroup B and 13 (5.6%) serogroup C meningococci. The national total of confirmed cases has remained relatively stable since 2006, but the number of cases may vary between jurisdictions each year. New South Wales had the highest number of recorded cases in 2009. Typical primary and secondary disease peaks were observed in those aged 4 years or less and in adolescents and young adults respectively. Serogroup B cases predominated in all age groups and jurisdictions. The common phenotypes circulating in Australia continue to be B:15:P1.7 and B:4:P1.4. Although serogroup C cases were low, phenotype C:2a:P1.5 again predominated in this group. No evidence of meningococcal capsular 'switching' was detected. Approximately two-thirds of all isolates showed decreased susceptibility to the penicillin group of antibiotics (MIC 0.06 to 0.5 mg/L). All isolates remained susceptible to ceftriaxone. Four isolates had reduced susceptibility to ciprofloxacin, and none to rifampicin.     

Enhanced surveillance scheme for suspected meningococcal disease in five regional health authorities in England: 1998

Enhanced surveillance of meningococcal disease (ESMD) began in five English regions on 1st January 1998. The aims of the scheme were to obtain accurate incidence data and develop a robust surveillance system with which to monitor the impact of a new meningococcal serogroup C conjugate vaccine. During 1998, 2,314 suspected cases of meningococcal disease were identified. The majority (84%) was classified as invasive meningococcal disease, with infection of N. meningitidis confirmed in 66%. Sixteen per cent of suspected cases were subsequently given an alternative diagnosis. Age differences between those classified as meningococcal disease and those not, implied a higher index of suspicion of meningococcal disease in younger children. Regions with high rates of meningococcal disease were due to a higher rate of serogroup C. ESMD increased ascertainment of meningococcal disease and deaths. Cases were 34% greater than identified through statutory notifications, an additional 6.8% confirmed infections were identified than were reported to the PHLS Meningococcal Reference Unit (MRU) and deaths were 24% greater than death registrations. These data were used to inform the national meningococcal serogroup C conjugate vaccination programme in England and Wales. In 1999 ESMD was extended to all regions of England, Wales and Northern Ireland.     

Epidemiology and economic burden of meningococcal disease in Germany: A systematic review

IntroductionInvasive meningococcal disease (IMD) is a notifiable disease in Germany and other European countries. Due to the high lethality of the disease and the risk of long-term consequences, IMD prevention is of high public health relevance despite the low number of cases in the population. This study aims to describe key epidemiological and economic parameters of IMD in Germany to support national decision-making processes for implementing enhanced prevention measures.MethodsBased on a systematic literature review in PubMed and EMBASE, all publications on the burden of disease and costs of IMD published up to May 2020 were evaluated. Additionally, notification data were used to report the annual case numbers and incidence of IMD in Germany until the end of 2019.ResultsThirty-six studies were included, of which 35 reported data on the epidemiological burden of disease and three reported data on economic aspects of IMD. The type of reported endpoints and results on the incidence of IMD differed widely by reporting year, population, and data source used. Most of the data are reported without specific information about a serogroup. Data on the economic burden of disease and healthcare resource use are scarce. Based on mandatory notification data, a decrease in the incidence of notified IMD cases has been observed since 2004. Currently, the nationwide annual incidence in Germany is at 0.3 cases per 100,000 persons and has gradually decreased. While the overall decline is mainly attributable to MenB, cases with MenY and MenW are the only ones that have increased on a low level in recent years.ConclusionWhile IMD is a rare disease, high direct and indirect costs illustrate the relevance of the disease for patients, caregivers, as well as for the health care system. Future research should concentrate on quantifying the long-term economic burden and indirect costs of meningococcal disease. Integrated IMD surveillance with isolate characterisation remains crucial to inform public health policies.     

Capture-recapture analysis to estimate the incidence of invasive meningococcal disease in Germany, 2003

The incidence of invasive meningococcal disease (IMD) in Germany in 2003 was estimated by the two-source capture-recapture method. As a unique personal identifier was unavailable, cases with IMD tested at the National Reference Centre for Meningococci (NRZM) were matched with cases reported to the Robert Koch Institute (RKI) through the statutory surveillance system by using demographic and disease-specific variables common to both datasets. The estimated overall incidence was 1.1 IMD cases/100,000 inhabitants, with a sensitivity of ascertainment of 64.8% for NRZM and 89.4% for RKI. Case-fatality rate was estimated at 8.8%. Adjustment for heterogeneity of capture according to age, region and serogroup observed in the NRZM (but not RKI) source had minimal effect on the estimated incidence. The IMD incidence estimated by capture-recapture analysis is thus only slightly higher than through statutory surveillance data. As a degree of positive dependence between the systems cannot be ruled out, this estimate may still be an underestimate. However, under ascertainment appears insufficient to explain the low incidence of IMD in Germany compared to other European countries.     

The changing epidemiology of meningococcal meningitis after introduction of bivalent A/C polysaccharide vaccine into school-based vaccination programs in Egypt

BACKGROUND: The strategy recommended by the World Health Organization (WHO) to curtail outbreaks of meningococcus in Africa is enhanced surveillance with administration of oily chloramphenicol as well as vaccination when incidence thresholds are exceeded. The role of capsular polysaccharide meningococcal vaccine in outbreak prevention has been the subject of considerable debate. The Egyptian Ministry of Health and Population initiated a school-based vaccination program with bivalent A/C capsular polysaccharide vaccine in 1992. This investigation reviews data on meningococcal meningitis in Egypt comparing years before and after introduction of the vaccine. METHODS: This is a retrospective review of several sources to examine the rates and serogroups of meningococcal meningitis before and after the introduction of the meningococcal A/C vaccine in Egypt. FINDINGS: Between 1967 and 1991, outbreaks of meningococcal disease were documented with a periodicity of 8 years in Egypt. However, there has not been an outbreak since 1991 and over the same period, there has also been a progressive decline in the baseline incidence of meningococcus. Also, a shift from a serogroup A to serogroup B predominance in meningococcal disease was noted during the study period. These data suggest that there has been an alteration in the epidemiology of meningococcal disease in Egypt that coincided with the implementation of the school-based vaccination program. INTERPRETATION: Routine use of the bivalent A/C meningococcal vaccine may be an alternative for the control and prevention of meningococcal disease in high-risk areas including the "meningitis belt".     

Invasive meningococcal disease in England and Wales: implications for the introduction of new vaccines

A number of meningococcal vaccines have either been recently licensed or are in late-phase clinical trials. To inform national vaccination policy, it is important to define the burden of disease and the potential impact of any new vaccine. This study describes the epidemiology of invasive meningococcal disease across all age groups in England and Wales for recent epidemiological years between 2006 and 2010. The Health Protection Agency (HPA) conducts enhanced national meningococcal surveillance through a combination of clinical and laboratory reporting. Between 2006/07 and 2010/11, the average annual incidence of invasive meningococcal disease across all age groups was 2.0/100,000. Capsular group B (MenB) accounted for 87% (4777/5471) cases, with an overall incidence of 1.8/100,000. The highest MenB incidence observed among infants (36.2/100,000) where cases increased from birth to 5 months of age then gradually declined. An annual average of 245 MenB cases occurred in infants (135 in those aged ≤ 6 months) representing 26% (and 14%) of all MenB cases, respectively. After infancy, MenB rates declined until the age of 12 years, rising to a second smaller peak at 18 years. MenB case fatality ratio (CFR) was 5.2% (247/4777 cases) overall and was highest among ≥ 65 year-olds (28/161; 17.4%). The largest number of deaths (n=125), however, occurred among <5 year-olds. Clonal complexes cc269 and cc41/44 each accounted for around a third of cases across the age groups. Other capsular groups rarely caused invasive disease, although capsular group Y (MenY) cases more than doubled from 35 in 2006/07 to 86 in 2010/11. Thus, universal meningococcal vaccination with an effective broad-spectrum formulation has potential to prevent most disease, particularly if the vaccine is immunogenic early in infancy, but, there is currently little justification for routine quadrivalent ACWY conjugate vaccination in the UK, although the increase in MenY disease warrants continued surveillance.     

Impact of systematic vaccination with the antimeningococcal C conjugated vaccine in a health area in Andalusia

BACKGROUND: A retrospective longitudinal study of population incidence was made to assess the effectiveness of meningococcal serogroup C conjugate vaccine, after its mass introduction in children in the geographic area of a health district, measuring its population impact, and we have studied the state of the meningococcal disease. METHODS: Vaccine coverage in children born between 1991 and 2001, and rates of incidence in declared cases of meningococcal disease in seven epidemiological seasons (1997/98 to 2003/04) were calculated. The impact of vaccination against serogroup C meningitis was assessed comparing the average annual rates of previous and later seasons to the vaccination campaigns in population younger and older than 10, using the Fisher exact test. RESULTS: In all the study period, 109 cases of meningococcal disease were declared, of which 50 were of serogroup C meningococcal disease. Starting from 2000/2001 season the incidence of serogroup C disease decreased in the population below 10. In this age group, the annual average rate of post-vaccine seasons decreases in respect to pre-vaccine (from 8.2 to 2.0 per 100,000 inhabitants) showing a statistically significant difference. In the population above 10 years, this incidence reduction was not observed. In the study period, no case of vaccine failure was declared. CONCLUSIONS: The absence of vaccine failure and the impact observed on the incidence of serogroup C meningococcal disease in children under 10 suggests the effectiveness of this new conjugate vaccine, together with suitable vaccination conditions (vaccination schedule, high catch-up, etc.) which are developing in our health district.     

Cost-effectiveness of meningococcal polysaccharide serogroups A,C, W-135 and Y conjugate vaccine in Australian adolescents

ObjectivesThe incidence of invasive meningitis disease (IMD) is increasing in Australia. A conjugate vaccine of meningococcal polysaccharide serogroups A, C, W and Y (MenACWY) is currently indicated for infants aged 12 months on the Australian National Immunisation Program. This study sought to determine the cost-effectiveness of a broader MenACWY vaccination program for Australians aged 15 to 19 years.MethodsA Markov model was constructed to simulate the incidence and consequences of IMD in Australians aged 0–84 years, with follow up until age 85 years. The model comprised four health states: ‘Alive with no previous IMD’, ‘Alive, post IMD without long-term complications’, ‘Alive, post IMD with long-term complications’ and ‘Dead’. Decision analysis compared the clinical consequences and costs of a vaccination program versus no vaccination from the perspective of the Australian health care system. Age-specific incidence of IMD and fatality rates were derived from Australian surveillance data. Vaccine coverage, vaccine efficacy and herd immunity were based on published data. The total cost for MenACWY vaccination was AU$56 per dose. Costs and health outcomes were discounted by 5% per annum (in the base-case analysis).ResultsCompared to no vaccination, a MenACWY vaccination program targeted at Australians aged 15–19 years was expected to prevent 1664 IMD cases in the Australian population aged 0–84 years followed up until age 85 years. The program would lead to 1131 life years (LYs) and 2058 quality adjusted life years (QALYs) gained at a total cost of AU$115 million (all discounted values). These equated to incremental cost-effectiveness ratios of AU$101,649 per LY gained and AU$55,857 per QALY gained. A probabilistic sensitivity analysis demonstrated a likelihood of cost-effectiveness of 34.6%, assuming a willingness to pay threshold of AU$50,000 per QALY gained.ConclusionThe likelihood of this program being cost-effective under a willingness to pay threshold AU$50,000 per QALY gained is 35%.     

Epidemiology of invasive meningococcal disease in north Queensland, 1995 to 1999.

This study describes all episodes of invasive meningococcal disease (n=120) acquired in north Queensland over the 5 year period 1995 to 1999. Indigenous people had a 3-fold greater risk than others of acquiring invasive meningococcal disease. There were 7 deaths, six in non-indigenous people. The majority (72.4%) of identified isolates were serogroup B. We found no evidence of significant resistance to the antibiotics recommended for treatment or chemoprophylaxis. Two outbreaks of disease were identified, one serogroup B and one serogroup C. Compared to the previous 5 years (1990 to 1994) there were far fewer cases of serogroup C disease and a lower incidence and risk of invasive meningococcal disease among indigenous people.     

Meningococcal C conjugate vaccine effectiveness before and during an outbreak of invasive meningococcal disease due to Neisseria meningitidis serogroup C/cc11, Tuscany,Italy

IntroductionIn Tuscany, Italy, where a universal immunization program with monovalent meningococcal C conjugate vaccine (MCC) was introduced in 2005, an outbreak of invasive meningococcal disease (IMD) due to the hypervirulent strain of Neisseria meningitidis C/cc11 occurred in 2015–2016, leading to an immunization reactive campaign using either the tetravalent (ACWY) meningococcal conjugate or the MCC vaccine. During the outbreak, IMD serogroup C (MenC) cases were also reported among vaccinated individuals. This study aimed to characterize meningococcal C conjugate vaccines (MenC-vaccines) failures and to estimate their effectiveness since the introduction (2005–2016) and during the outbreak (2015–2016).MethodsMenC cases and related vaccine-failures were drawn from the National Surveillance System of Invasive Bacterial Disease (IBD) for the period 2006–2016. A retrospective cohort-study, including the Tuscany' population of the birth-cohorts 1994–2014, was carried out. Based on annual reports of vaccination, person-years of MenC-vaccines exposed and unexposed individuals were calculated by calendar-year, birth-cohort, and local health unit. Adjusted (by birth-cohort, local health unit, and calendar-year) risk-ratios (ARR) of MenC invasive disease for vaccinated vs unvaccinated were estimated by the Poisson model. Vaccine-effectiveness (VE) was estimated as: VE = 1-ARR.ResultsIn the period 2006–2016, 85 MenC-invasive disease cases were reported; 61 (71.8%) from 2015 to 2016. Twelve vaccine failures occurred, all of them during the outbreak. The time-interval from immunization to IMD onset was 20 days in one case, from 9 months to 3 years in six cases, and ≥7 years in five cases. VE was, 100% (95%CI not estimable, p = 0.03) before the outbreak (2006–2014) and 77% (95%CI 36–92, p < 0.01) during the outbreak; VE was 80% (95%CI 54–92, p < 0.01) during the overall period.ConclusionsIn Tuscany, MenC-vaccine failures occurred exclusively during the 2015–2016 outbreak. Most of them occurred several years after vaccination. VE during the outbreak-period was rather high supporting an effective protection induced by MenC-vaccines.