Invasive meningococcal disease in England: assessing disease burden through linkage of multiple national data sources

Global Meningococcal Initiative: Insights on antibiotic resistance, control strategies and advocacy efforts in Western Europe

In Western Europe, many countries have robust and well-established surveillance systems and case reporting mechanisms. IMD incidence across Western Europe is low with a predominance of meningococcal serogroup B (MenB). Case confirmation and antimicrobial susceptibility testing is often standardised in this region, with many countries also having robust vaccination programmes in place. Both MenB and MenACWY vaccines form part of National Immunisation Programmes (NIPs) in most European countries, with Sweden only offering vaccination in special circumstances. Despite these established programmes, there remains a critical need for advocacy efforts in affecting change in diagnosis, testing, and treatment. Recent campaigns, such as the World Meningitis Day digital toolkit, have helped raise awareness and draw attention to meningococcal disease. Awareness around antibiotic resistance has also led to the identification of antibiotic-resistant meningococcal strains, with an increase, albeit small, in these strains noted across the region. Countries such as Spain, Portugal, Germany, Switzerland, and France have either reported strains resistant to penicillin, ciprofloxacin and/or isolates with a reduced susceptibility to third-generation cephalosporins.

Risk of Invasive Meningococcal Disease in Preterm Infants

Background

Invasive meningococcal disease (IMD) is most common in the first year of life. We hypothesized that preterm infants may have a higher risk of IMD and more severe disease than term infants. We compared the incidence, demographics, clinical presentation, and outcomes of IMD in preterm compared with term infants during the first 5 years after implementation of a national meningococcal group B vaccine (4CMenB) for infants in England.

Methods

The UK Health Security Agency conducts enhanced national IMD surveillance with detailed follow-up of all confirmed cases in England. Infants aged <1 year (uncorrected for gestational age) with IMD confirmed between 1 September 2015 and 31 August 2020 were included.

Results

There were 393 infant IMD cases (incidence, 12.4/100 000 live births). Among 363 (92.4%) of the infants with known gestational age, the IMD incidence was higher in preterm (<37 weeks' gestation) than in term infants (18.3/100 000 vs 10.9/100 000; incidence rate ratio [IRR], 1.68 [95% confidence interval, 1.23-2.29]; P = .001). The IMD incidence was highest in those born at <32 weeks' gestation (32.9/100 000; incidence rate ratio for <32 weeks' gestation vs term, 3.01 [95% confidence interval, 1.73-5.24]; P ≤ .001). There were no differences in demographics, clinical presentation, rate of intensive care admission, or case-fatality rate, but preterm infants were more likely than term infants to have ≥1 reported sequela (14 of 39 [35.9%] vs 51 of 268 [19.0%]; P = .02).

Conclusions

Preterm infants had a higher incidence of IMD than term infants and the IMD incidence was highest in infants born at <32 weeks' gestation. Preterm infants also had a higher risk of IMD sequelae.

Invasive serogroup B meningococci in England following three years of 4CMenB vaccination - First real-world data

OBJECTIVES

In 2015 the UK became the first country to implement the meningococcal B (MenB) vaccine, 4CMenB, into the national infant program. 4CMenB is expected to cover meningococci expressing sufficient levels of cross-reactive proteins. This study presents clonal complex, 4CMenB antigen genotyping, and 4CMenB coverage data for all English invasive MenB isolates from 2014/15 (1 year pre-vaccine) through 2017/18 and compares data from vaccinated and unvaccinated ≤3 year olds.

METHODS

Vaccine coverage of all invasive MenB isolates from 2014/15 to 2017/18 (n = 784) was analysed using the Meningococcal Antigen Typing System. Genotyping utilised the Meningococcus Genome Library.

RESULTS

Among ≤3 year olds, proportionally fewer cases in vaccinees (1, 2 or 3 doses) were associated with well-covered strains e.g. cc41/44 (20.5% versus 36.4%; P<0.01) and antigens e.g. PorA P1.4 (7.2% versus 17.3%; P = 0.02) or fHbp variant 1 peptides (44.6% vs 69.1%; P<0.01). Conversely, proportionally more cases in vaccinees were associated with poorly-covered strains e.g. cc213 (22.9% versus 9.6%; P<0.01) and antigens e.g. variant 2 or 3 fHbp peptides (54.2% versus 30.9%; P<0.01).

CONCLUSIONS

4CMenB reduces disease due to strains with cross-reactive antigen variants. No increase in absolute numbers of cases due to poorly covered strains was observed in the study period.

Invasive Meningococcal Disease, 2011-2020, and Impact of the COVID-19 Pandemic, England

Invasive meningococcal disease incidence in England declined from 1.93/100,000 persons (1,016 cases) in 2010–11 to 0.95/100,000 (530 cases) in 2018–19 and 0.74/100,000 in 2019–20 (419 cases). During national lockdown for the coronavirus disease pandemic (April–August 2020), incidence was 75% lower than during April–August 2019.

First real world evidence of meningococcal group B vaccine, 4CMenB, protection against meningococcal group W disease; prospective enhanced national surveillance, England

BACKGROUND

4CMenB is a protein-based meningococcal group B vaccine but the vaccine antigens may also be present on non-group B meningococci. In September 2015, the UK implemented 4CMenB into the national infant immunisation programme, alongside an emergency adolescent meningococcal ACWY (MenACWY) programme to control a national outbreak of group W (MenW) disease caused by a hypervirulent strain belonging to the ST11 clonal complex. The adolescent programme aimed to provide direct protection for adolescents and, over time, indirect (herd) protection across the population.

METHODS

Public Health England conducts meningococcal disease surveillance in England. MenW cases confirmed during four years before and four years after implementation of both vaccines were analysed. Poisson models were constructed to estimate direct protection against MenW disease offered by the infant 4CMenB programme on top of the indirect impact of the adolescent MenACWY programme in children eligible for 4CMenB but not MenACWY.

RESULTS

Model estimates showed 69% (adjusted incidence rate ratio (IRR) 0.31, 95%CI, 0.20-0.67) and 52% (aIRR 0.48, 95%CI 0.28-0.81) fewer MenW cases than predicted among age-cohorts that were fully-eligible and partly-eligible for 4CMenB, respectively. There were 138 MenW cases in &5 year-olds. 4CMenB directly prevented 98 (95%CI, 34-201) cases, while the MenACWY programme indirectly prevented an additional 114 (conservative) to 899 (extreme) cases over four years. Disease severity was similar in 4CMenB-immunised and unimmunised children.

CONCLUSIONS

Our results provide the first real-world evidence of the direct protection afforded by 4CMenB against MenW:cc11 disease. 4CMenB has the potential to provide some protection against all meningococcal serogroups.

Increase of invasive meningococcal serogroup W disease in Europe, 2013 to 2017

BackgroundThe total incidence of invasive meningococcal disease (IMD) in Europe has been declining in recent years; however, a rising incidence due to serogroup W (MenW), predominantly sequence type 11 (ST-11), clonal complex 11 (cc11), was reported in some European countries.AimThe aim of this study was to compile the most recent laboratory surveillance data on MenW IMD from several European countries to assess recent trends in Europe.MethodsIn this observational, retrospective study, IMD surveillance data collected from 2013-17 by national reference laboratories and surveillance units from 13 European countries were analysed using descriptive statistics.ResultsThe overall incidence of IMD has been stable during the study period. Incidence of MenW IMD per 100,000 population (2013: 0.03; 2014: 0.05; 2015: 0.08; 2016: 0.11; 2017: 0.11) and the proportion of this serogroup among all invasive cases (2013: 5% (116/2,216); 2014: 9% (161/1,761); 2015: 13% (271/2,074); 2016: 17% (388/2,222); 2017: 19% (393/2,112)) continuously increased. The most affected countries were England, the Netherlands, Switzerland and Sweden. MenW was more frequent in older age groups (≥ 45 years), while the proportion in children (< 15 years) was lower than in other age groups. Of the culture-confirmed MenW IMD cases, 80% (615/767) were caused by hypervirulent cc11.ConclusionDuring the years 2013-17, an increase in MenW IMD, mainly caused by MenW cc11, was observed in the majority of European countries. Given the unpredictable nature of meningococcal spread and the epidemiological potential of cc11, European countries may consider preventive strategies adapted to their contexts.

Serogroup C Neisseria meningitidis disease epidemiology, seroprevalence, vaccine effectiveness and waning immunity, England, 1998/99 to 2015/16

Background

In 1999, the United Kingdom (UK) was the first country to introduce meningococcal group C (MenC) conjugate vaccination. This vaccination programme has evolved with further understanding, new vaccines and changing disease epidemiology.

Aim

To characterise MenC disease and population protection against MenC disease in England.

Methods

Between 1998/99–2015/16, surveillance data from England for laboratory-confirmed MenC cases were collated; using the screening method, we updated vaccine effectiveness (VE) estimates. Typing data and genomes were obtained from the Meningitis Research Foundation Meningococcus Genome Library and PubMLST Neisseria database. Phylogenetic network analysis of MenC cc11 isolates was undertaken. We compared bactericidal antibody assay results using anonymised sera from 2014 to similar data from 1996–1999, 2000–2004 and 2009.

Results

MenC cases fell from 883 in 1998/99 (1.81/100,000 population) to 42 cases (0.08/100,000 population) in 2015/16. Lower VE over time since vaccination was observed after infant immunisation (p = 0.009) and a single dose at 1–4 years (p = 0.03). After vaccination at 5–18 years, high VE was sustained for ≥ 8 years; 95.0% (95% CI: 76.0– 99.5%). Only 25% (75/299) children aged 1–14 years were seroprotected against MenC disease in 2014. Recent case isolates mostly represented two cc11 strains.

Conclusion

High quality surveillance has furthered understanding of MenC vaccines and improved schedules, maximising population benefit. The UK programme provides high direct and indirect protection despite low levels of seroprotection in some age groups. High-resolution characterisation supports ongoing surveillance of distinct MenC cc11 lineages.

Transmissibility and pathogenicity of the emerging meningococcal serogroup W sequence type-11 complex South American strain: a mathematical modeling study

BACKGROUND

The recent emergence of strains belonging to the meningococcal serogroup W (MenW) sequence type-11 clonal complex and descending from the South American sub-lineage (MenW:cc11/SA) has caused significant shifts in the epidemiology of meningococcal disease worldwide. Although MenW:cc11/SA is deemed highly transmissible and invasive, its epidemiological characteristics have not yet been quantified.

METHODS

We designed a mathematical model of MenW transmission, carriage, and infection to analyze the recent epidemiology of invasive disease caused by MenW:cc11/SA strains and by other MenW strains in England and in France. We confronted that model with age-stratified incidence data to estimate the transmissibility and the invasiveness of MenW:cc11/SA in England, using the data in France as a validation cohort.

RESULTS

During the epidemiological years 2010/2011-2014/2015 in England, the transmissibility of MenW:cc11/SA relative to that of other MenW strains was estimated at 1.20 (95% confidence interval, 1.15 to 1.26). The relative invasiveness of MenW:cc11/SA was also found to exceed unity and to increase with age, with estimates ranging from 4.0 (1.6 to 9.7) in children aged 0-4 years to 20 (6 to 34) in adults aged ≥ 25 years. In France, the model calibrated in England correctly reproduced the early increase of MenW:cc11/SA disease during 2012/2013-2016/2017. Most recent surveillance data, however, indicated a decline in MenW:cc11/SA disease. In both countries, our results suggested that the transmission of MenW:cc11/SA carriage possibly started several months before the first reported case of MenW:cc11/SA disease.

DISCUSSION

Our results confirm earlier suggestions about the transmission and the pathogenic potential of MenW:cc11/SA. The main limitation of our study was the lack of age-specific MenW carriage data to confront our model predictions with. Furthermore, the lesser model fit to the most recent data in France suggests that the predictive accuracy of our model might be limited to 5-6 years.

CONCLUSIONS

Our study provides the first estimates of the transmissibility and of the invasiveness of MenW:cc11/SA. Such estimates may be useful to anticipate changes in the epidemiology of MenW and to adapt vaccination strategies. Our results also point to silent, prolonged transmission of MenW:cc11/SA carriage, with potentially important implications for epidemic preparedness.

Vaccination of Infants with Meningococcal Group B Vaccine (4CMenB) in England

BACKGROUND

In September 2015, the United Kingdom introduced the multicomponent meningococcal group B vaccine (4CMenB, Bexsero) into its publicly funded national immunization program at a reduced two-dose priming schedule for infants, with a 12-month booster.

METHODS

Using data from enhanced national surveillance of invasive meningococcal disease in England, we evaluated the effect of vaccination on the incidence of meningococcal group B disease during the first 3 years of the program. The effect of vaccination was assessed by comparing the observed incidence of disease with the expected incidence based on the incidence during the 4-year prevaccination period in equivalent cohorts and with the use of disease trends in cohorts of children younger than 5 years of age who were not eligible to receive the vaccine. Vaccine effectiveness was estimated with the use of the indirect screening method.

RESULTS

4CMenB uptake in England remained consistently high; data from the first 3 months of 2018 showed that 92.5% of children had completed the primary immunizations by their first birthday and 87.9% had received all three doses by 2 years. From September 2015 through August 2018, the incidence of meningococcal group B disease in England (average annual birth cohort, approximately 650,000 infants) was significantly lower in vaccine-eligible cohorts than the expected incidence (63 observed cases as compared with 253 expected cases; incidence rate ratio, 0.25; 95% confidence interval [CI], 0.19 to 0.36), with a 75% reduction in age groups that were fully eligible for vaccination. The adjusted vaccine effectiveness against meningococcal group B disease was 52.7% (95% CI, -33.5 to 83.2) with a two-dose priming schedule for infants and 59.1% (95% CI, -31.1 to 87.2) with a two-dose priming schedule plus a booster at 1 year). Over the 3-year period, there were 169 cases of meningococcal group B disease in the vaccine-eligible cohorts, and an estimated 277 cases (95% CI, 236 to 323) were prevented.

CONCLUSIONS

The 4CMenB program was associated with continued positive effect against meningococcal group B disease in children in England, and protection after three doses of the vaccine was sustained for at least 2 years. (Funded by Public Health England.).

Variable clinical presentation by the main capsular groups causing invasive meningococcal disease in England

BACKGROUND

Invasive meningococcal disease (IMD) typically presents as meningitis, septicaemia or both. Atypical clinical presentations are rare but well-described. We aimed to assess the relationship between meningococcal capsular group, age, clinical presentation, diagnosis and outcome among IMD cases diagnosed in England during 2014.

METHODS

Public Health England conducts enhanced national surveillance of IMD in England. Clinical data for laboratory-confirmed MenB, MenW and MenY cases in ≥5 year-olds were used to classify presenting symptoms, diagnosis and outcomes. Multivariable logistic regression was used to assess independent associations between meningococcal capsular group, clinical presentation, gender, age and death.

RESULTS

In 2014, there were 340 laboratory-confirmed IMD cases caused by MenB (n = 179), MenW (n = 95) and MenY (n = 66). Clinical presentation with meningitis alone was more prevalent among MenB cases (28%) and among 15-24 year-olds (20%), whilst bacteraemic pneumonia was most prevalent among MenY cases (26%) and among ≥65 year-olds (24%). Gastrointestinal symptoms were recorded preceding or during presentation in 15% (40/269) cases with available information, including 5% (7/140) MenB, 17% (8/47) MenY and 30% (25/82) MenW cases. Upper respiratory tract symptoms were reported in 16% (22/141) MenB, 23% (11/47) MenY and 31% (26/84) MenW cases. Increasing age was also independently associated with bacteraemic meningococcal pneumonia, with no cases among 5-14 year-olds compared to 24% in ≥65 year-olds. Case fatality rates increased with age but no significant associations with death were identified.

CONCLUSIONS

Healthcare professionals should be aware of the atypical clinical presentations associated with the less prevalent meningococcal capsular groups in different age-groups.

Risk of invasive meningococcal disease in university students in England and optimal strategies for protection using MenACWY vaccine

PURPOSE

In August 2015, in response to increasing group W invasive meningococcal disease (IMD) nationally, a MenACWY vaccine programme was introduced in the UK for 13-18year olds. We reviewed the epidemiology of IMD in young adults and university-associated cases in England during 2014-15 academic year and assessed the potential impact of different immunisation strategies.

METHODS

Public Health England national enhanced surveillance data were used to describe the epidemiology of IMD cases in 15-24year olds in England during 2014/15. Relative risks for IMD were calculated overall and by capsular group in students compared with non- student peers for 2014 and 2013 school leavers. Assuming stable future incidence and vaccine efficacy of 90% for five years, we estimated cases averted and numbers needed to vaccinate (NNV) for different MenACWY immunisation programmes: school-based adolescent, GP-based school leaver, and targeting freshers.

RESULTS

Between July 2014 and June 2015, 112 IMD cases were diagnosed in those born between 01/09/1991 and 31/08/2001 (∼15 to 24year-olds). During the 2014/15 academic year (September to June), 49 IMD cases were reported among students attending English universities, including 22 among 2014 school leavers. In this cohort, the relative risk of IMD was higher among students compared to non-students for all capsular groups (RR 11.6; 95% CI 4.7-28.7) and for groups A/C/W/Y (RR 14.8; 95% CI, 4.3-51.5). A school-based programme could potentially have averted 14 cases in 2014/15 and 24 cases over five years with a lower NNV (18,000) than other programmes.

CONCLUSIONS

University students, particularly first years entering direct from school, are at higher risk for IMD than non-students. With high vaccine coverage and timely completion, an adolescent school-based MenACWY programme has the greatest potential to prevent cases with the lowest NNV, but population impact through indirect (herd) protection could take longer.

Emergency Meningococcal ACWY Vaccination Program for Teenagers to Control Group W Meningococcal Disease, England, 2015-2016

During the first 12 months of an emergency meningococcal ACWY vaccination program for teenagers in England, coverage among persons who left school in 2015, the first cohort to be vaccinated, was 36.6%. There were 69% fewer group W meningococcal cases than predicted by trend analysis and no cases in vaccinated teenagers.

Safety and Immunogenicity of the Quadrivalent Meningococcal Serogroups A, C, W and Y Tetanus Toxoid Conjugate Vaccine Coadministered With Routine Childhood Vaccines in European Infants: An Open, Randomized Trial

BACKGROUND

This was the first study evaluating the immunogenicity and safety of the quadrivalent meningococcal tetanus toxoid conjugate vaccine (MenACWY-TT) coadministered with routine childhood vaccines in young infants.

METHODS

In this open, randomized, controlled, phase III study (NCT01144663), 2095 infants (ages 6-12 weeks) were randomized (1:1:1:1) into 4 groups to receive MenACWY-TT at 2, 3, 4 and 12 months of age, or MenACWY-TT, MenC-cross-reactive material (CRM197) or MenC-TT at 2, 4 and 12 months of age. All participants received PHiD-CV and DTPa-HBV-IPV/Hib at 2, 3, 4 and 12 months of age. Immune responses were measured by serum bactericidal activity assays using rabbit (rSBA) and human (hSBA) complement. Solicited and unsolicited symptoms were recorded during 8 and 31 days post-vaccination, respectively, and serious adverse events throughout the study.

RESULTS

Noninferiority of immune responses to MenC induced by 2 or 3 doses of MenACWY-TT versus 2 doses of MenC-TT or MenC-CRM197 was demonstrated. Predefined criteria for the immunogenicity of MenACWY-TT to MenA, MenW and MenY were met. One month after 2 or 3 primary MenACWY-TT doses, ≥93.1% and ≥88.5% of infants had rSBA and hSBA titers ≥1:8 for all serogroups. The robust increases in rSBA and hSBA titers observed for all vaccine serogroups postbooster vaccination suggested that MenACWY-TT induced immune memory. MenACWY-TT coadministered with childhood vaccines had a clinically acceptable safety profile.

CONCLUSIONS

This study supports the coadministration of MenACWY-TT with routine childhood vaccines as 2 or 3 primary doses during infancy followed by a booster dose in the second year of life.

Effectiveness and impact of a reduced infant schedule of 4CMenB vaccine against group B meningococcal disease in England: a national observational cohort study

BACKGROUND

In September, 2015, the UK became the first country to introduce the multicomponent group B meningococcal (MenB) vaccine (4CMenB, Bexsero) into a publicly funded national immunisation programme. A reduced two-dose priming schedule was offered to infants at 2 months and 4 months, alongside an opportunistic catch-up for 3 month and 4 month olds. 4CMenB was predicted to protect against 73-88% of MenB strains. We aimed to assess the effectiveness and impact of 4CMenB in vaccine-eligible infants in England.

METHODS

Public Health England (PHE) undertakes enhanced surveillance of meningococcal disease through a combination of clinical, public health, and laboratory reporting. Laboratory-confirmed cases of meningococcal disease are followed up with PHE local health protection teams, general practitioners, and hospital clinicians to collect demographic data, vaccination history, clinical presentation, and outcome. For cases diagnosed between Sept 1, 2015, and June 30, 2016, vaccine effectiveness was assessed using the screening method. Impact was assessed by comparing numbers of cases of MenB in vaccine-eligible children to equivalent cohorts in the previous 4 years and to cases in vaccine-ineligible children.

FINDINGS

Coverage of 4CMenB in infants eligible for routine vaccination was high, achieving 95·5% for one dose and 88·6% for two doses by 6 months of age. Two-dose vaccine effectiveness was 82·9% (95% CI 24·1-95·2) against all MenB cases, equivalent to a vaccine effectiveness of 94·2% against the highest predicted MenB strain coverage of 88%. Compared with the prevaccine period, there was a 50% incidence rate ratio (IRR) reduction in MenB cases in the vaccine-eligible cohort (37 cases vs average 74 cases; IRR 0·50 [95% CI 0·36-0·71]; p=0·0001), irrespective of the infants' vaccination status or predicted MenB strain coverage. Similar reductions were observed even after adjustment for disease trends in vaccine-eligible and vaccine-ineligible children.

INTERPRETATION

The two-dose 4CMenB priming schedule was highly effective in preventing MenB disease in infants. Cases in vaccine-eligible infants halved in the first 10 months of the programme. While ongoing national surveillance will continue to monitor the longer-term impact of the programme, these findings represent a step forward in the battle against meningococcal disease and will help reassure that the vaccine protects against this deadly infection.

FUNDING

Public Health England.

The importance of surveillance: Group W meningococcal disease outbreak response and control in England

Invasive meningococcal disease (IMD) is associated with high morbidity and mortality. Recently, use of the quadrivalent MenACWY conjugate vaccines has increased with the emergence of a hypervirulent MenW:cc11 strain in certain parts of the world, especially South America. In England, MenW:cc11 IMD cases increased rapidly after 2009 and was responsible for 24% of all IMD cases in 2014/15 compared to <5% previously, leading to the emergency introduction of a national teenage MenACWY conjugate vaccine programme in August 2015. Unusually, MenW:cc11 cases have been described presenting with severe gastrointestinal symptoms, including abdominal pain and diarrhoea, followed by rapid clinical deterioration and death.