Invasive Meningococcal Disease Cases Research Articles

Invasive meningococcal infections in children during the 1998–2001 hyper-endemic period in Switzerland

Pediatric cases of invasive meningococcal disease (IMD) during the 1998 to 2001, hyperendemic period in Switzerland, were investigated. Retrospective analysis of confirmed and probable cases of IMD, in patients

Disease Burden of Invasive Meningococcal Disease in the Netherlands Between June 1999 and June 2011: A Subjective Role for Serogroup and Clonal Complex.

Several countries consider the implementation of a meningococcal serogroup B vaccine for young children and/or serogroup C or ACWY conjugate vaccine for adolescents. Representative information on clinical course of invasive meningococcal disease (IMD) is useful to evaluate cost-effectiveness of vaccination. Information on the relation between infecting meningococcal clonal complex (CC), disease course and outcome of IMD is scarce. A retrospective study using Dutch surveillance data on IMD from June 1999 to June 2011. Clinical information was retrieved from hospital records. The effect of age, comorbidity, clinical manifestation, serogroup, and CC on disease course and outcome was assessed in multivariable analyses. Meningococcal CCs were assessed by multilocus sequence typing. Clinical information was retrieved for 879 IMD cases: 48% of patients presented with meningitis, 17% with septic shock, and 22% with septic shock plus meningitis. Development of septic shock was not related to CC or serogroup. Median (interquartile range) duration of hospital admission was 10 (8-13) days. Intensive care unit admittance (38%) was higher for patients aged ≥10 years and patients with septic shock (P-values ≤.001). Case-fatality rate (8%) and development of sequelae (29%) was dependent on age and clinical manifestation (P-values ≤.001) and not affected by comorbidity, CC, or serogroup. IMD still coincides with a considerable disease burden and mortality. Disease course and outcome depend mainly on age and clinical manifestation and less on meningococcal CC or serogroup.

Group B Meningococcal Disease on Campus Again

In the U.S., Neisseria meningitidis serogroup B (MenB) is responsible for about half of all cases of invasive meningococcal disease in people aged 17 to 22. Recently, two MenB vaccines were licensed for use in this country. On February 2, 2015, a case of MenB disease was reported in a male student attending Providence College. Three days later, …

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.

Chemoprophylaxis and vaccination in preventing subsequent cases of meningococcal disease in household contacts of a case of meningococcal disease: a systematic review.

Household contacts of an index case of invasive meningococcal disease (IMD) are at increased risk of acquiring disease. In revising WHO guidance on IMD in sub-Saharan Africa, a systematic review was undertaken to assess the effect of chemoprophylaxis and of vaccination in preventing subsequent cases of IMD in household contacts following an index case. A literature search for systematic reviews identified a single suitable review on chemoprophylaxis in 2004 (three studies meta-analysed). A search for primary research papers published since 2004 on chemoprophylaxis and without a date limit on vaccination was therefore undertaken. There were 2381 studies identified of which two additional studies met the inclusion criteria. The summary risk ratio for chemoprophylaxis vs. no chemoprophylaxis (four studies) in the 30-day period after a case was 0·16 [95% confidence interval (CI) 0·04-0·64, P = 0·008]; the number needed to treat to prevent one subsequent case was 200 (95% CI 111-1000). A single quasi-randomized trial assessed the role of vaccination. The risk ratio for vaccination vs. no vaccination at 30 days was 0·11 (95% CI 0·01-2·07, P = 0·14). The results support the use of chemoprophylaxis to prevent subsequent cases of IMD in household contacts of a case. Conclusions about the use of vaccination could not be drawn.

Health and economic outcomes of introducing the new MenB vaccine (Bexsero) into the Italian routine infant immunisation programme.

IntroductionIn January 2013 a novel type of multicomponent protein-based vaccine against group B meningococcal disease was licensed by the European Medicines Agency. With the widespread use of the meningococcal serogroup C conjugate vaccines, serogroup B remains now the major cause of bacterial meningitis and septicaemia in young children in Europe. The aim of this study is to investigate the health and the economic outcomes of MenB vaccine introduction into the Italian routine mass vaccination programme.MethodsThe present work is structured in two main parts. Firstly, we assess the epidemiological burden of group B meningococcal disease using official hospitalisation and notification data from two of the most populated Italian regions (Lombardia and Piemonte) during a 6-year study period (2007-2012). Secondly, we evaluate the cost-effectiveness of the immunisation programme in Italy from the public health payer perspective under base case parameters assumptions and performing a comprehensive sensitivity analysis to assess the robustness and the uncertainty of our model results.ResultsMenB serotype is responsible for 59% of the 341 cases of Invasive Meningococcal Disease in Lombardia and Piemonte. Incidence rate for MenB infection is estimated to be 0.21/100,000/y resulting at the highest level in children ≤4 years of age. Although the new MenB vaccine can potentially prevent about one third of the disease cases in the Italian population, model results show this strategy is unlikely to be cost-effective (ICER value over €350,000/QALY) with a vaccine that prevents disease only. These results are robust under most of the sensitivity scenarios except when allowing for lower discount rates.DiscussionThe introduction of the novel vaccine into the routine immunisation schedule needs to be carefully evaluated. The new MenB vaccine has the potential to reduce the disease burden at the population level. However, from the Italian Health Service perspective, the immunisation programme is unlikely to be cost-effective at the current incidence levels and vaccine price.

Twenty years of surveillance of Invasive Meningococcal Diseases in Puglia, Italy.

The study aims to investigate the change in the burden of disease and the microbiological characteristics of Invasive Meningococcal Disease (IMD) in Puglia in comparison with overall incidence from 1994 through 2014. Data are gathered in the frame of the National Surveillance System coordinated by the National Reference Laboratory (NRL) of the Istituto Superiore di Sanità. In Puglia, from 1994 through 2014, the average incidence of IMD was 0.2 per 100 000 inhabitants, below the national average value (0.33). IMD cases tended to be older than the other cases reported in Italy (median age 19 vs 16). The case-fatality rate was 20.4% in Puglia vs 13.3% in Italy. Serogroups B and C were most frequently identified. Serogroups C and Y presented a fairly clonal pattern, whereas serogroup B was genetically rather heterogeneous. Surveillance systems are critical in monitoring any change in the epidemiology of IMD.

Characterization of invasive Neisseria meningitidis from Atlantic Canada, 2009 to 2013: With special reference to the nonpolysaccharide vaccine targets (PorA, factor H binding protein, Neisseria heparin-binding antigen and Neisseria adhesin A).

Serogroup B Neisseria meningitidis (MenB) has always been a major cause of invasive meningococcal disease (IMD) in Canada. With the successful implementation of a meningitis C conjugate vaccine, the majority of IMD in Canada is now caused by MenB. To investigate IMD case isolates in Atlantic Canada from 2009 to 2013. Data were analyzed to determine the potential coverage of the newly licensed MenB vaccine. Serogroup, serotype and serosubtype antigens were determined from IMD case isolates. Clonal analysis was performed using multilocus sequence typing. The protein-based vaccine antigen genes were sequenced and the predicted peptides were investigated. The majority of the IMD isolates were MenB (82.5%, 33 of 40) and, in particular, sequence type (ST)-154 B:4:P1.4 was responsible for 47.5% (19 of 40) of all IMD case isolates in Atlantic Canada. Isolates of this clone expressed the PorA antigen P1.4 and possessed the nhba genes encoding for Neisseria heparin-binding antigen peptide 2, which together matched exactly with two of the four components of the new four-component meningococcal B vaccine. Nineteen MenB isolates had two antigenic matches, another five MenB and one meningitis Y isolate had one antigenic match. This provided 75.8% (25 of 33) potential coverage for MenB, or a 62.5% (25 of 40) overall potential coverage for IMD. From 2009 to 2013, IMD in Atlantic Canada was mainly caused by MenB and, in particular, the B:4:P1.4 ST-154 clone, which accounted for 47.5% of all IMD case isolates. The new four-component meningococcal B vaccine appeared to offer adequate coverage against MenB in Atlantic Canada.

Draft Genome Sequence of C:P1.5-1,10-8:F3-6:ST-11 Meningococcal Clinical Isolate Associated with a Cluster on a Cruise Ship.

Meningococcal serogroup C strains, in particular those belonging to the ST-11 clonal complex, are known to cause invasive diseases worldwide. We report the genome sequence of a Neisseria meningitidis strain linked to a cluster of cases of invasive meningococcal disease on a cruise ship that was described in 2012.

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

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. 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). 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). 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.

Climate, demographic factors and geographical variations in the incidence of invasive meningococcal disease in Italy.

We investigated the effect of climatic, demographic factors and intra-country geographical variations on the incidence of invasive meningococcal disease (IMD) in Italy. For this purpose, incidence rates of IMD cases reported in Italy between 1994 and 2012 were calculated, and a cluster analysis was performed. A geographical gradient was determined, with lower incidence rates in central and southern Italy, compared to the northern parts, where most clusters were observed. IMD rates were higher in medium-sized towns than in villages. Adults were at lower risk of IMD than children aged ⩽4 years. IMD incidence tended to decrease with increasing monthly mean temperatures (incidence rate ratio 0·94, 95% confidence interval 0·90-0·99). In conclusion, geographical variations in IMD incidence were found, where age and temperature were associated with disease occurrence. Whether geographical variations should be considered in national intervention plans is still a matter for discussion.

Power-law models for infectious disease spread

Short-time human travel behaviour can be described by a power law with respect to distance. We incorporate this information in space-time models for infectious disease surveillance data to better capture the dynamics of disease spread. Two previously established model classes are extended, which both decompose disease risk additively into endemic and epidemic components: a spatio-temporal point process model for individual-level data and a multivariate time-series model for aggregated count data. In both frameworks, a power-law decay of spatial interaction is embedded into the epidemic component and estimated jointly with all other unknown parameters using (penalised) likelihood inference. Whereas the power law can be based on Euclidean distance in the point process model, a novel formulation is proposed for count data where the power law depends on the order of the neighbourhood of discrete spatial units. The performance of the new approach is investigated by a reanalysis of individual cases of invasive meningococcal disease in Germany (2002-2008) and count data on influenza in 140 administrative districts of Southern Germany (2001-2008). In both applications, the power law substantially improves model fit and predictions, and is reasonably close to alternative qualitative formulations, where distance and order of neighbourhood, respectively, are treated as a factor. Implementation in the R package surveillance allows the approach to be applied in other settings.

Determination of serotyping antigens, clonal analysis and genetic characterization of the 4CMenB vaccine antigen genes in invasive Neisseria meningitidis from Western Canada, 2009 to 2013

This study examined invasive Neisseria meningitidis recovered from invasive meningococcal disease (IMD) cases in Western Canada between 2009 and 2013. A total of 161 isolates from individual IMD cases were analysed for serogroup, serotype, serosubtype, PorA genotype, multi-locus sequence type and nucleotide sequence of their 4CMenB vaccine antigen genes. Sixty-nine isolates were serogroup B (MenB), 47 were serogroup Y (MenY), 22 were serogroup C (MenC), 19 were serogroup W (MenW), three were serogroup E and one was non-encapsulated. MenC, MenY and MenW were mainly clonal, represented primarily by clonal complex (cc) 11, cc23 or cc167, and cc22, respectively. In contrast, MenB were composed of eight different ccs together with 11 isolates not assigned to any known cc. Antigenic analysis and PorA genotyping confirmed the heterogeneity of MenB isolates, while such results supported the clonal nature of most MenC, MenY and MenW isolates. Thirty-four (21.1%) isolates had at least one gene that encoded one matching vaccine protein component of the 4CMenB vaccine (i.e. PorA P1.4; fHbp variant 1.1; NHBA peptide 2; and NadA-1, -2, or -3). An additional 18 isolates had genes that encoded variant 1 or subfamily B factor H binding proteins of this same vaccine.

A new meningococcal B vaccine

Neisseria meningitidis is an important cause of invasive bacterial infection in children worldwide, and is a rare example of a bacterium that has evolved to become an obligate human commensal which commonly colonizes the oropharyngeal mucosa. Carriage is age-dependent and appears to be very common in young adults. The relationships between carriage and invasive disease are not completely understood [1]. Each year approximately 1.2 million cases of invasive meningococcal disease (sepsis or meningitis) with 135,000 deaths are estimated to occur worldwide [2]. Epidemiology and serogroup distribution differs geographically, as the example in Figure 1 shows, with invasive disease mainly affecting young children, older children and young adults. In addition to age, another individual risk factor includes underlying immune deficiencies; the deficiency of complement components is a known risk factor for invasive infection. Crowding and concurrent upper respiratory tract infections might also contribute to the disease. In early 2013, a new vaccine developed specifically to prevent disease caused by group B meningococci (MenB)

Epidemiology of invasive meningococcal disease in the Netherlands, 1960–2012: an analysis of national surveillance data

Epidemiological data for invasive meningococcal disease is essential for public health policy and vaccine development. We analysed national surveillance data from the Netherlands for PorA coverage of two PorA-based meningococcal serogroup B vaccines to describe the epidemiology of invasive meningococcal disease. We examined national surveillance data from the Netherlands Reference Laboratory of Bacterial Meningitis (NRLBM) for cases of culture-positive invasive meningococcal disease from Jan 1, 1960, to Jan 1, 2013. We included cases with a meningococcal isolate cultured from cerebrospinal fluid, blood, skin biopsy, or all, and cases with a positive cerebrospinal fluid latex agglutination test, counter current electrophoresis test, or positive cerebrospinal fluid PCR for Neisseria meningitidis. To test for completeness of case ascertainment, we compared data of the NRLBM with those of the Dutch National institute for public health and the environment (RIVM) to which notification was compulsory. We did serogrouping by ouchterlony gel diffusion. We tested susceptibility of meningococcal strains by agar dilution and E test. We tested differences between proportions with the Pearson χ(2) test or Fisher's exact test, and differences in frequencies between time periods with the Mann-Whitney U test. We defined penicillin resistance as MIC of 1·0 μg/mL or higher. Annual incidence rates of invasive meningococcal disease per 100 000 population increased from 0·5 in 1960, to 4·5 in 2001, and subsequently decreased to 0·6 in 2012. Median age increased from 1·8 years in 1960, to 6·1 years in 2012 for all serogroups. The proportion of blood culture positive cases increased from 4% in 1960, to 60% in 2012 (p<0·0001). Serogroup B was the most common serogroup over time, 64% of isolates were from ST-41/44 complex. We established PorA finetype of 4133 isolates, 19 of 252 variable regions covered 99% of sequenced serogroup B cases. Coverage of the 4CMenB PorA component was 4% in 1960-65, and 36% in 2006-12. In response to a serogroup C epidemic (1999-2001), serogroup C conjugate vaccine was introduced, which reduced serogroup C disease by 95%. Since 2003, serogroup Y disease emerged and serogroup A disease disappeared. We identified evidence of capsular switching, but not of serogroup replacement. The rate of reduced penicillin susceptibility increased to 37% from 1993 to 2012, but penicillin resistance was not recorded. Incidence of invasive meningococcal disease has decreased, but decreasing rates of penicillin susceptibility and the possible resurgence of this devastating disease remain a threat to public health. Our long-term serosubtyping and porA sequencing data is valuable for the assessment of vaccine coverage and future serogroup B vaccine development. National Institute of Public Health and the Environment, the European Union's seventh Framework programme, Netherlands Organization for Health Research and Development, Academic Medical Center, and the European Research Council.

Vigilancia de laboratorio de enfermedad meningocóccica invasora en Chile, 2006-2012

Laboratory surveillance of Invasive Meningococcal Disease (IMD) is performed by the Institute of Public Health of Chile. It confirms identification, classifies in serogroups and analyzes the genetic profiles of Neisseria meningitidis isolates from laboratories throughout the country. To show the results of this surveillance from 2006 to 2012. A descriptive data analysis of the confirmed cases of IMD and serological characterization, susceptibility and genetic profiles of the isolates. The analysis was disaggregated by serogroup, age and region. From 2006 to 2012, 486 isolates of N. meningitidis were confirmed. In 2011 a rise in IMD rates was observed due to an increase in W serogroup cases, mainly affecting children aged 5 years or less. Serogroup W became the most prevalent during 2012 (58.3%), replacing the historically prevalent serogroup B. Predominating strains belonged to ST-32 complex/ET-5 complex (40, 4% of strains) and ST-41/44 complex/ Lineage 3 (45, 9% of strains). Laboratory surveillance has allowed the early detection of increasing IMD caused by serogroup W, which is emergent in Chile. This information has reinforced the daily monitoring of new cases, in collaboration with all the clinical laboratories of the country.

The missing link: Family physician perspectives on barriers and enablers to prescribing a new Meningococcal B vaccine and other recommended, non-government funded vaccines

ObjectivesTo determine factors influencing Family Physician (FP) uptake of non government-funded vaccines, and to explore FP attitudes towards the introduction and use of a new vaccine to protect against serogroup B meningococcal disease to inform its future introduction into the Australian Immunisation Schedule. Design setting and participantsQuantitative, self-administered state-wide questionnaire mailed to all FPs in South Australia (n=1786). Results from 523 FP respondents in South Australia, collected between June and October 2013. Main outcome measuresSelf-reported immunisation counselling practices; and knowledge, attitudes and barriers to prescribing of Meningococcal B (Men B) vaccine and other recommended, non-funded immunisations. ResultsThe response rate was 30% (n=523). While most (59%) respondents had worked in general practice for over 20 years, only 39% of all respondents had ever had personal or professional experience with a case of invasive meningococcal disease (IMD). Most FPs (63%) were aware that a meningococcal B vaccine was being developed, and 93% of respondents agreed that this vaccine should be government-funded. FPs ranked Men B vaccine as the highest priority to receive funding of eight currently non-funded immunisation strategies. High vaccine cost and low patient socioeconomic status were identified as definite barriers to prescribing non-funded vaccines by 59% of respondents. Past IMD experience significantly affected attitudes and prescribing practices. ConclusionsIMD, while encountered rarely in clinical practice, is considered an important disease to vaccinate against by FPs. Cost and perceived low socioeconomic status of patients are substantial barriers to FPs prescribing Men B and other non-funded vaccines, and inclusion of such vaccines on the National Immunisation Program is likely to improve equity of access.

New South Wales annual vaccine-preventable disease report, 2012.

We aim to describe the epidemiology of selected vaccine-preventable diseases in New South Wales (NSW) for 2012. Data from the NSW Notifiable Conditions Information Management System were analysed by: local health district of residence, age, Aboriginality, vaccination status and organism, where available. Risk factor and vaccination status data were collected by public health units for cases following notification under the NSW Public Health Act 2010. The largest outbreak of measles since 1998 was reported in 2012. Pacific Islander and Aboriginal people were at higher risk as were infants less than 12 months of age. Notifications of invasive pneumococcal disease (IPD) in children less than fiveyears declined; however, the overall number of notifications for IPD increased. Mumps case notifications were also elevated. There were no Haemophilus influenzae type b case notifications in children less than fiveyears of age for the first time since the vaccine was introduced. Invasive meningococcal disease case notifications were at their lowest rates since case notification began in 1991. Case notification rates for other selected vaccine-preventable diseases remained stable. Vaccine-preventable disease control is continually strengthening in NSW with notable successes in invasive bacterial infections. However, strengthening measles immunization in Pacific Islander and Aboriginal communities remains essential to maintain measles elimination.

Enhanced surveillance of invasive meningococcal disease in Canada, 2006-2011.

The purpose of this report is to describe the epidemiology of invasive meningococcal disease (IMD) in Canada from 2006 to 2011. Data from the Enhanced Invasive Meningococcal Disease Surveillance System and national population estimates were selected for descriptive and inferential analyses. The geographic, demographic, seasonal and subtype distributions as well as clinical characteristics of the IMD cases were examined. Incidence and mortality rates were calculated per 100,000 population per year; 95% confidence intervals (CI) were calculated for rate comparison. The direct method was used for age standardization. Proportions were compared using the chi-squared test at a p<0.05 significance level. During the study period, the mean incidence rates of IMD were 0.58 (total), 0.33 (serogroup B), 0.07 (serogroup C), 0.03 (serogroup W-135) and 0.10 (serogroup Y). The median age for serogroups B, C, W-135 and Y was 16, 43, 38 and 47 years respectively. The mean age-specific incidence rates among infants under 1 year of age (7.35, CI: 5.38-9.32) and children from 1 to 4 years of age (1.89, CI: 1.54-2.24) were significantly higher than those in any other age group. The mean case fatality ratio was 8.1% (range 4.3%-14.3%). The average number of cases that occurred per month was significantly higher (p<0.0001) in winter (18 cases) than in summer (12 cases). IMD is still endemic in Canada. Although individuals at any age can be affected, infants under 1 year of age are at the greatest risk, followed by children aged 1-4 years and individuals aged 15-19 years. Following the implementation of routine childhood immunization programs with monovalent meningococcal C conjugate vaccines (MenC) in all provinces and territories (beginning in 2007), the incidence of serogroup C has decreased significantly over the study period and is now at an all-time low. Serogroup B is the leading cause of IMD, and diseases of serogroup W-135 and Y have stabilized at relatively lower incidence rates. With the addition of immunization programs using quadrivalent conjugate meningococcal vaccines (MCV4), we would expect further reductions in the incidence of meningococcal infection in Canada.

Sustained outbreak of measles in New South Wales, 2012: risks for measles elimination in Australia

Little information is available publicly on invasive meningococcal disease (IMD) in elderly people in Australia. This study analysed IMD notifications data from New South Wales between 1993 and 2012 to determine the distribution of IMD among people aged 65 years and older and to describe the characteristics of IMD in this age group compared to younger age groups with respect to notification trends, serogroup distribution and mortality rates. Following introduction of a childhood vaccination programme against meningococcal type C in 2003, notification rates in all age groups decreased, but the proportion of IMD notifications in people aged 65 years and over rose significantly (from 4% to 6%, P=0.01). Mortality rates from IMD in those aged 65 years and older were significantly higher than overall rates (32% compared to 5%, P<0.01). Serogroup Y accounted for 23% of infections in the elderly compared to 3% in people aged under 65 years (P<0.01). As the population ages, the elderly may account for a higher number of IMD cases in Australia. Protocols at the state and national level should be updated to provide guidance on the clinical and public health management of elderly people with IMD.