The threat of meningococcal disease during the Hajj and Umrah mass gatherings: A comprehensive review

Invasive meningococcal disease in older adults: current perspectives and call for action

PURPOSE

Invasive meningococcal disease (IMD) is a devastating condition. While most attention is directed towards disease in children and adolescents, IMD poses an important cause of morbidity and mortality in adults ≥60 years. While immunization is a critical component of healthy ageing strategies, meningococcal immunization is not routinely offered to older adults. The aim of this review was to summarize clinical and epidemiological aspects of IMD and available immunization strategies, with a particular focus on disease in older individuals, to emphasize the importance of this rather neglected area.

METHODS

An expert working group was established to evaluate clinical and epidemiological data to raise awareness of IMD in older individuals, and develop suggestions to improve the existing burden.

RESULTS

Routine child and adolescent meningococcal immunization has substantially reduced IMD in these targeted populations. Consequently, prevalence and proportion of IMD among those ≥60 years, mostly unvaccinated, is increasing in developed countries (accounting for up to 25% of cases). IMD-related mortality is highest in this age-group, with substantial sequelae in survivors. IMD due to serogroups W and Y is more prevalent among older adults, often with atypical clinical features (pneumonia, gastrointestinal presentations) which may delay timely treatment.

CONCLUSIONS

IMD in older adults remains overlooked and greater awareness is required at clinical and societal levels. We encourage clinicians and immunization policy makers to reconsider IMD, with a call for action to remedy existing inequity in older adult access to protective meningococcal immunization.

Parental Knowledge Toward Meningococcal Disease and Vaccination in Makkah Region, Saudi Arabia: A Cross-Sectional Study

Background Invasive meningococcal disease (IMD) is a bacterial infection caused by Neisseria meningitidis, which primarily affects the meninges, with a high incidence in young children. The most effective technique for preventing IMD is vaccination, which has been available for over 40 years through meningococcal polysaccharide capsule-containing vaccines. This study aims to assess the parental knowledge of meningococcal disease and vaccination in the Makkah region of Saudi Arabia. Methodology A cross-sectional study was conducted between September and December 2023 among 597 parents in the Makkah region using a validated online survey. The collected data were analyzed using the Statistical Package for the Social Sciences (SPSS). Results The study sample included 597 parents, of which 339 (56.8%) were female and 258 (43.2%) were male. Our research demonstrated that 388 (65%) participants had an insufficient understanding of IMD, while 209 (35%) had a sufficient understanding. There was a significant correlation between the knowledge score and the completion of the routine vaccination and whether vaccinating a child is essential for the protection of other members of society. Conclusions Based on our study, only around one-third of the participants demonstrated a sufficient level of knowledge regarding IMD and its vaccination. To provide a more accurate assessment of the Saudi population, additional research should be conducted in various regions and cities.

A mathematical interpretation for outbreaks of bacterial meningitis under the effect of time-dependent transmission parameters

We consider a SIR-type compartmental model divided into two age classes to explain the seasonal exacerbations of bacterial meningitis, especially among children outside of the meningitis belt. We describe the seasonal forcing through time-dependent transmission parameters that may represent the outbreak of the meningitis cases after the annual pilgrimage period (Hajj) or uncontrolled inflows of irregular immigrants. We present and analyse a mathematical model with time-dependent transmission. We consider not only periodic functions in the analysis but also general non-periodic transmission processes. We show that the long-time average values of transmission functions can be used as a stability marker of the equilibrium. Furthermore, we interpret the basic reproduction number in case of time-dependent transmission functions. Numerical simulations support and help visualize the theoretical results.

Carriage of Neisseria meningitidis among travelers attending the Hajj pilgrimage, circulating serogroups, sequence types and antimicrobial susceptibility: A multinational longitudinal cohort study

BACKGROUND

Travel to international mass gatherings such as the Hajj pilgrimage increases the risk of Neisseria meningitidis transmission and meningococcal disease. We investigated carriage and acquisition of N. meningitidis among travelers to Hajj and determined circulating serogroups, sequence types and antibiotic susceptibility among isolates.

METHOD

We conducted a multinational longitudinal cohort study among 3921 traveling pilgrims in two phases: Pre-Hajj and Post-Hajj. For each participant, a questionnaire was administered and an oropharyngeal swab was obtained. N. meningitidis was isolated, serogrouped, and subjected to whole genome sequence analysis and antibiotic susceptibility testing.

RESULTS

Overall carriage and acquisition rates of N. meningitidis were 0.74% (95%CI: 0.55-0.93) and 1.10% (95%CI: 0.77-1.42) respectively. Carriage was significantly higher Post-Hajj (0.38% vs 1.10%, p = 0.0004). All isolates were nongroupable, and most belonged to the ST-175 complex and were resistant to ciprofloxacin with reduced susceptibility to penicillins. Three potentially invasive isolates (all genogroup B) were identified in the Pre-Hajj samples. No factors were associated with Pre-Hajj carriage. Suffering influenza like illness symptoms and sharing a room with >15 people were associated with lower carriage Post-Hajj (adjOR = 0.23; p = 0.008 and adjOR = 0.27; p = 0.003, respectively).

CONCLUSION

Carriage of N. meningitidis among traveler to attending Hajj was low. However, most isolates were resistant to ciprofloxacin used for chemoprophylaxis. A review of the current meningococcal disease preventive measures for Hajj is warranted.

Meningococcal disease within the Gulf Cooperation Council Countries

This review reports on the recent epidemiology of invasive meningococcal disease (IMD) within the Gulf Cooperation Council (GCC) Countries (focusing from 2012 onwards), the existing immunization strategies and the potential for IMD resurgence. MenACWY vaccination is now established in infant or adolescent immunization programs in Saudi Arabia, Bahrain, Kuwait, and the United Arab Emirates. At present, GCC Countries do not include MenB immunization. National health surveillance reports indicate a total of 156 IMD cases reported across the GCC Countries between 2012 and 2021; between 30% and 80% of cases were reported in individuals aged ≥15 years. Lack of serogroup data hinders the assessment of vaccine impact and decision-making on additional vaccine introductions (e.g. MenB immunization). Hajj/Umrah pilgrimage and the increasing number of large-scale commercial and social events held in the GCC Countries pose a potential risk for future IMD outbreaks. Immunization policies for such events could be strengthened.

Immunogenicity and safety of MenACWY-TT, a quadrivalent meningococcal tetanus toxoid conjugate vaccine recently licensed in the United States for individuals ≥2 years of age

Vaccination offers the best way to prevent invasive meningococcal disease (IMD). As demonstrated in countries with national immunization programs (NIPs) against IMD, meningococcal conjugate vaccines have contributed to significant declines in incidence. Since some meningococcal vaccines are associated with modest immunogenicity in infants, possible immunological interference upon concomitant administration with some pediatric vaccines, and administration errors resulting from improper reconstitution, opportunities for improvement exist. A quadrivalent conjugate vaccine, MenQuadfi® (Meningococcal [Serogroups A, C, Y, and W] Conjugate Vaccine; Sanofi, Swiftwater, Pennsylvania), was approved in 2020 for the prevention of IMD caused by meningococcal serogroups A, C, W, and Y in individuals ≥2 years of age in the United States. Five pivotal studies and one ancillary study supported approval in the United States; clinical trials in infants are ongoing. Data on the immunogenicity and safety of this vaccine are presented, and its potential value in clinical practice is discussed.

Carriage of Neisseria meningitidis Among Umrah Pilgrims: Circulating Serogroups and Antibiotic Resistance

Background

Meningococcal disease and outbreaks are a risk during mass gatherings such as the Umrah religious pilgrimage to the Kingdom of Saudi Arabia (KSA). We aimed to investigate the carriage of Neisseria meningitidis among the 2019 Umrah pilgrims and determine the circulating serogroups and their antibiotic susceptibility profiles.

Methods

We conducted a cross-sectional study among adult Umrah pilgrims from 17th to 29th April 2019 in Mecca city, KSA. A questionnaire was administered to each participant, and an oropharyngeal swab was obtained. Microbiological techniques were used to isolate, identify and serogroup N. meningitidis from the swabs. E-tests were used to determine the susceptibility of the isolates to nine antibiotics.

Results

The study enrolled 616 pilgrims from 17 countries with a mean age of 53.8 years (±13.1, range = 19–91) and a male-to-female ratio of 1.1:1. Nearly 39% of the respondents had no formal education, 32.5% declared having an underlying health condition and 17.2% were current or past smokers. During their Umrah stay, most pilgrims reported sharing accommodation (98.5%) and never using a face mask (98.5%). Also, 34.6% reported suffering from influenza-like symptoms and 11.8% used antibiotics. N. meningitidis was isolated from three pilgrims (carriage rate of 0.49%), two were serogroup A and one was serogroup B. Antibiotic susceptibility results were available for one isolate (serogroup B) which showed resistance to ciprofloxacin and decreased susceptibility to trimethoprim-sulfamethoxazole.

Conclusion

Carriage of N. meningitidis among Umrah pilgrims was low. However, invasive serogroups were identified, including an isolate resistant to ciprofloxacin used for chemoprophylaxis. Meningococcal disease preventive measures for Umrah should be regularly reviewed and updated accordingly to reduce the risk of the disease and future pilgrimage-associated outbreaks.

Meningococcal Disease and Immunization Activities in Hajj and Umrah Pilgrimage: a review

Invasive meningococcal disease (IMD) outbreaks associated with Hajj and Umrah pilgrimage events in the Kingdom of Saudi Arabia (KSA) are well recognized. Past outbreaks have been associated with substantial intercontinental spread of specific Neisseria meningitidis serogroups. The emergence of meningococcal serogroup W (MenW) was a global concern following the 2000/2001 Hajj outbreaks. Broader compulsory meningococcal serogroups A, C, W and Y (MenACWY) immunization strategies for pilgrims were introduced in response to these events and led to substantial declines in IMD cases associated with these mass gatherings. However, there remains potential for future outbreaks either within KSA during the Hajj or in local populations via pilgrim meningococcal transmission on their return. While the annual Hajj involves pilgrims from over 185 countries, two-thirds of these arrive from 13 countries, chiefly from across South-East Asia, the Middle East and North African (MENA) regions; for which we review the relevant epidemiology of IMD and meningococcal carriage. While disease surveillance is limited and data are often lacking, MenB is an important serogroup associated with IMD and carriage in a number of countries. Available literature suggests that most pilgrims receive polysaccharide MenACWY vaccines (which do not impact carriage and onward transmission) and incomplete compliance with visa/entry immunization regulations is reported. Existing preventative approaches for visiting pilgrims require continued oversight. More complete compliance and switching to the conjugated MenACWY vaccine can provide more robust and broader protection for pilgrims. Additional immunization options could also be considered.

Identification of the nasopharyngeal carriage of Neisseria meningitidis by 16S rRNA Gene sequencing in asymptomatic adolescents and young adults in Cartagena, Colombia (2019–2020)

The bacterium Neisseria meningitidis, a strictly human pathogen, can cause meningitis, meningococcemia, sepsis, and death; repeatedly it scause outbreaks around the world. The frequency of asymptomatic carriage is often high in adolescents and young adults, increasing the invasive meningococcal disease risk and likelihood of transmission. However, detailed analyses of meningococcal carriage in this population in Colombia, particularly in coastal areas, are lacking. In this study, the prevalence and characteristics of Neisseria meningitidis carriage were evaluated in asymptomatic adolescents and young adults (11-25 years old) in Cartagena, Colombia. Oropharynx samples were collected from participants between August and December 2019. The phenotypic identification of bacteria was performed by conventional methods and biochemical testing. Molecular identification to the species level was performed by 16S rRNA gene sequencing. In total, 12 of 648 samples were positive for Neisseria meningitidis by 16S rRNA sequencing, indicating a prevalence of 1.9%. Isolates were classified into four invasive serogroups (A, B, C, and W) by a comparative sequence analysis of the ribosomal gene. Despite the occurrence of meningococcal disease in Cartagena city in the last several years, the frequency of oropharyngeal carriage in adolescents and young adults was low. Serogroup A had not been previously reported in nasopharyngeal samples in Colombia. This is the first report of Neisseria meningitidis on the Colombian Caribbean coast based on 16S rRNA sequencing and is expected to guide the development of vaccination and follow-up strategies.

The changing face of meningococcal infection

Menigococcal infection is caused by Neisseria meningitidis, a Gram negative diplococci. Invasive meningococcal disease (IMD) is caused by 6 capsular groups. The spectrum of infection is broad, with meningitis and meningococcal sepsis associated with a case fatality of between 4 and 20%. The main burden of disease is felt in the under 1's and this is where vaccination has been focused. Vaccination against MenC begun in 1999, with vaccines against Men ACWY and MenB added to the schedule in 2015. Over the last 1o years rates of IMD in the UK have fallen by over 50%. The impact of COVID-19 on cases has also been felt, with early data suggesting a significant drop in cases during the first wave in 2020. Despite the success of vaccination we need to remain vigilant. Clonal expansion of hypervirulent strains has been seen in epidemics and we have a significant proportion of the population who remain unvaccinated.

Social determinants of health and primary immunodeficiency

OBJECTIVE

Inborn errors of immunity (IEI) are rare genetic conditions affecting the immune system. The rate of IEI and their presentation, course, and treatment are all affected by a multitude of social determinants, eventually affecting prognosis. This review summarizes the current knowledge of the social determinants affecting infectious susceptibility, genetic predisposition, diagnosis, and treatment of IEI.

DATA SOURCES

PubMed.

STUDY SELECTIONS

Search terms included "consanguinity," "social determinants," and "founder effect." Further studies were selected based on relevant citations.

RESULTS

Changes in climate and human behavior have modulated the spread of disease vectors and infectious organisms. Consanguinity increases the rate of autosomal recessive conditions, changes the distribution, and affects the severity of IEI. Access to sophisticated genetic and immunologic diagnostic modalities affects genetic counseling and timely diagnosis. Effective genetic counseling should address to the patient's genetic background and ethical code. Access to appropriate and timely treatment of immunodeficiencies is scarce in some regions of the world.

CONCLUSION

High consanguinity rate and reduced access to prophylactic measures increase the burden of immunodeficiencies in many low- and medium-income countries. Furthermore, poor access to diagnostic and treatment modalities in these regions adversely affects patients' prognosis. Increased awareness among health care professionals and the public and increased collaboration with Western countries aid in diagnosis of these conditions. Further advancements require improved public funding to the prevention, diagnosis, and treatment of IEI.

A novel vaccine to prevent meningococcal disease beyond the first year of life: an early review of MenACYW-TT

INTRODUCTION

Although quadrivalent meningococcal conjugate vaccines have been effective in preventing invasive meningococcal disease (IMD) caused by serogroups A, C, W, and Y across age groups from infants to adults, data on their efficacy and safety in adults ≥56 years of age are lacking. Moreover, multiple available quadrivalent conjugate vaccines require reconstitution prior to administration, introducing the potential for error. A novel quadrivalent meningococcal conjugate vaccine, MenACYW-TT (MenQuadfi®) was approved in 2020 for use in individuals ≥12 months of age as a single dose in the European Union and some other countries and in individuals ≥2 years of age in the United States.

AREAS COVERED

The findings of Phase II/III studies that included >6600 individuals and evaluated the immunogenicity and safety of MenACYW-TT beyond the first year of life are comprehensively summarized and discussed.

EXPERT OPINION

Extensive data on immunogenicity and safety, co-administration with routine vaccines, elicitation of robust booster responses, and significantly higher Men C responses versus monovalent MenC or MenACWY standard-of-care vaccines in toddlers suggest that MenACYW-TT may be suitable for inclusion in National Immunization Programs (NIPs) globally. The authors provide their perspectives on the clinical use of MenACYW-TT across age groups from toddlers through adults.

The Epidemiology of Invasive Meningococcal Disease in the Kingdom of Saudi Arabia: A Narrative Review with Updated Analysis

Reducing invasive meningococcal disease (IMD) through MenACWY immunization is a critical healthcare strategy in the Kingdom of Saudi Arabia (KSA). Robust IMD surveillance is essential to help assess the need for additional immunization initiatives in target populations. This is particularly important in KSA, where mass gatherings accompanying Hajj/Umrah pilgrimages have been associated with IMD outbreaks within the local KSA population, and subsequent intercontinental spread via returning pilgrims. This narrative review of the published literature describes the changing epidemiology of IMD in KSA to provide a perspective on the impact of current immunization strategies and potential gaps. As recent published surveillance data are lacking, we also evaluated publicly reported data from the KSA Ministry of Health (MoH) for 2012–2019 to inform more recent IMD trends. Between 1995 and 2011, national surveillance data indicate that 1103 IMD cases were reported in KSA: 60% in 2000–2001, involving two (mainly MenW) outbreaks involving KSA citizens/residents and pilgrims focused in Mecca and Medina. Across 2002–2011, 184 cases of IMD were reported, with a higher proportion occurring in KSA citizens/residents, and with less focus within pilgrimage centers than apparent in previous years. Our analysis of MoH data found that, between 2012 and 2019, 44 IMD cases were reported, all in KSA citizens/residents, and chiefly in children or infants. No pilgrimage-associated outbreaks have occurred since 2001. Serogroup data were available for 62.5% of all cases for 2002–2011; MenW (40.0%), MenA (35.7%), and MenB (16.5%). Serogroup data for 2012–2019 remain incompletely reported, and the existing surveillance system could be improved, as some element of underestimation/underreporting of IMD may exist. While existing MenACWY immunization strategies for KSA citizens/residents and visiting pilgrims have been successful in reducing IMD due to specific serogroups, disease due to MenB remains a potential risk, and additional immunization strategies should be considered.

Mass gatherings: a review of the scope for meningococcal vaccination in the Indian context

The risk of meningococcal transmission is increased with crowding and prolonged close proximity between people. There have been numerous invasive meningococcal disease (IMD) outbreaks associated with mass gatherings and other overcrowded situations, including cramped accommodation, such as student and military housing, and refugee camps. In these conditions, IMD outbreaks predominantly affect adolescents and young adults. In this narrative review, we examine the situation in India, where the burden of IMD-related complications is significant but the reported background incidence of IMD is low. However, active surveillance for meningococcal disease is suboptimal and laboratory confirmation of meningococcal strain is near absent, especially in non-outbreak periods. IMD risk factors are prevalent, including frequent mass gatherings and overcrowding combined with a demographically young population. Since overcrowded situations are generally unavoidable, the way forward relies on preventive measures. More widespread meningococcal vaccination and strengthened disease surveillance are likely to be key to this approach.

Infections in Immunosuppressed Travellers with Autoimmune Inflammatory Diseases-A Narrative Review and Advice for Clinical Practice

The management of autoimmune, inflammatory diseases has been revolutionized by biologic therapies. A beneficial consequence of better disease control is that more patients are well enough to travel the world. There is now a class of traveller, the significantly immunosuppressed person with autoimmune disease, with specific risks and requirements. This review introduces the concept of the pre-travel risk assessment and discusses the major vaccine-preventable and non-vaccine-preventable travel-associated infections. The challenges and controversies around vaccination and immunosuppression are reviewed with advice for clinical practice.

The environmental drivers of bacterial meningitis epidemics in the Democratic Republic of Congo, central Africa

INTRODUCTION

Bacterial meningitis still constitutes an important threat in Africa. In the meningitis belt, a clear seasonal pattern in the incidence of meningococcal disease during the dry season has been previously correlated with several environmental parameters like dust and sand particles as well as the Harmattan winds. In parallel, the evidence of seasonality in meningitis dynamics and its environmental variables remain poorly studied outside the meningitis belt. This study explores several environmental factors associated with meningitis cases in the Democratic Republic of Congo (DRC), central Africa, outside the meningitis belt area.

METHODS

Non-parametric Kruskal-Wallis' tests were used to establish the difference between the different health zones, climate and vegetation types in relation to both the number of cases and attack rates for the period 2000-2018. The relationships between the number of meningitis cases for the different health zones and environmental and socio-economical parameters collected were modeled using different generalized linear (GLMs) and generalized linear mixed models (GLMMs), and different error structure in the different models, i.e., Poisson, binomial negative, zero-inflated binomial negative and more elaborated multi-hierarchical zero-inflated binomial negative models, with randomization of certain parameters or factors (health zones, vegetation and climate types). Comparing the different statistical models, the model with the smallest Akaike's information criterion (AIC) were selected as the best ones. 515 different health zones from 26 distinct provinces were considered for the construction of the different GLM and GLMM models.

RESULTS

Non-parametric bivariate statistics showed that there were more meningitis cases in urban health zones than in rural conditions (χ2 = 6.910, p-value = 0.009), in areas dominated by savannah landscape than in areas with dense forest or forest in mountainous areas (χ2 = 15.185, p-value = 0.001), and with no significant difference between climate types (χ2 = 1.211, p-value = 0,449). Additionally, no significant difference was observed for attack rate between the two types of heath zones (χ2 = 0.982, p-value = 0.322). Conversely, strong differences in attack rate values were obtained for vegetation types (χ2 = 13.627, p-value = 0,001) and climate types (χ2 = 13.627, p-value = 0,001). This work demonstrates that, all other parameters kept constant, an urban health zone located at high latitude and longitude eastwards, located at low-altitude like in valley ecosystems predominantly covered by savannah biome, with a humid tropical climate are at higher risk for the development of meningitis. In addition, the regions with mean range temperature and a population with a low index of economic well-being (IEW) constitute the perfect conditions for the development of meningitis in DRC.

CONCLUSION

In a context of global environmental change, particularly climate change, our findings tend to show that an interplay of different environmental and socio-economic drivers are important to consider in the epidemiology of bacterial meningitis epidemics in DRC. This information is important to help improving meningitis control strategies in a large country located outside of the so-called meningitis belt.

Geographically widespread invasive meningococcal disease caused by a ciprofloxacin resistant non-groupable strain of the ST-175 clonal complex

INTRODUCTION

Invasive meningococcal disease (IMD) caused by non-serogroupable (NG) strains mainly affects immunocompromised individuals. Reduced susceptibility to penicillin in meningococci is increasing in Europe but ciprofloxacin resistance remains rare. In 2019, three travel-related meningococcal disease cases caused by a ciprofloxacin-resistant NG strain were identified in England, leading Germany to report four additional IMD cases (2016 to 2019). We describe these and newly identified cases and characterise the strain responsible.

METHODS

Cases were identified as part of national surveillance and by analysing available genomes using PubMLST tools.

RESULTS

Of the cases identified in England in 2019, two geographically distinct cases developed conjunctivitis after returning from Mecca (Kingdom of Saudi Arabia) and a third linked case presented with IMD. Of the four cases from Germany, three occurred in asylum seekers - two familial and a further geographically distinct case. Further IMD cases were identified in Italy (n = 2; 2017-2018), Sweden (n = 1; 2016) and England (n = 1; 2015). A single ST-175 clonal complex (cc175) strain with genosubtype P1.22-11,15-25 was responsible. Decreased susceptibility to penicillin was widespread with three ciprofloxacin resistant subclusters. Constituent isolates were potentially covered by subcapsular vaccines.

CONCLUSION

This disease associated NG cc175 strain exhibits resistance to antibiotics commonly used to prevent IMD but is potentially covered by subcapsular (meningococcal B) vaccines.

Meningococcal and pneumococcal carriage in Hajj pilgrims: findings of a randomized controlled trial

BACKGROUND

Intense congestion during the Hajj pilgrimage amplifies the risk of meningococcal carriage and disease, and there have been many meningococcal outbreaks reported amongst pilgrims. Thus, a strict vaccination policy is enforced by the host country and either polysaccharide or conjugate quadrivalent meningococcal vaccines are mandatory. However, unlike conjugate vaccines, the polysaccharide vaccine is not thought to reduce pharyngeal carriage of meningococci.

METHODS

A single-blinded, randomized, controlled trial amongst pilgrims from Saudi Arabia and Australia during the Hajj seasons of 2016-2017 was conducted to compare MenACWY-Conjugate vaccine with MenACWY-Polysaccharide vaccine, to determine if the conjugate vaccine is more effective in reducing asymptomatic carriage of meningococci, and whether the effect may be long-standing. Oropharyngeal swabs were obtained pre-, immediately post- and 6-11 months following completion of Hajj and tested for the presence of meningococci.

RESULTS

Amongst 2000 individuals approached, only 1146 participants aged 18-91 (mean 37.6) years agreed to participate and were randomized to receive either the polysaccharide (n = 561) or the conjugate (n = 561) vaccine, 60.8% were male, and 93.5% were from Saudi Arabia. Amongst oropharyngeal swabs obtained before Hajj, only two (0.2%) tested positive for Neisseria meningitidis. Similarly, meningococci were identified in only one sample at each of the post-Hajj and late follow-up visits. None of the carriage isolates were amongst the serogroups covered by the vaccines. A post hoc analysis of the third swabs revealed that 22.4% of all participants (50/223) were positive for Streptococcus pneumoniae nucleic acid.

CONCLUSION

The low overall carriage rate of meningococci found amongst Hajj pilgrims in 2016 and 2017 demonstrates a successful vaccination policy, but neither supports nor refutes the superiority of meningococcal conjugate ACWY vaccine over the polysaccharide vaccine against carriage. Although an association could not be established in this study, molecular epidemiology would help to establish the role of Hajj in facilitating transmission of pneumococci and inform vaccination policy.

Immunogenicity and safety of a quadrivalent meningococcal tetanus toxoid-conjugate vaccine (MenACYW-TT) in ≥56-year-olds: A Phase III randomized study

BACKGROUND

Invasive meningococcal disease has a high mortality rate in individuals aged ≥56 years, but no vaccine is currently licensed in the USA for this age group. This study assessed the safety and immunogenicity of an investigational quadrivalent meningococcal tetanus toxoid conjugate vaccine (MenACYW-TT) compared with a meningococcal quadrivalent polysaccharide vaccine (MPSV4) in this age group.

METHODS

This was a Phase III, modified double-blind, randomized, non-inferiority study (NCT02842866) across 35 clinical sites in the USA and Puerto Rico in individuals aged ≥56 years. A single dose of the MenACYW-TT (n = 451) or MPSV4 vaccine (n = 455) was administered on Day 0. A serum bactericidal assay with human (hSBA) and baby rabbit (rSBA) complement was used to measure antibodies against serogroups A, C, W, and Y test strains at baseline and Day 30. Safety data were collected up to six months post-vaccination.

RESULTS

The seroresponse to MenACYW-TT was non-inferior to MPSV4 for each of the serogroups (A: 58.2% vs. 42.5%; C: 77.1% vs. 49.7%; W: 62.6% vs. 44.8%, Y: 74.4% vs. 43.4%, respectively). At Day 30, participants achieving hSBA titers ≥1:8 were higher for all serogroups after MenACYW-TT vs. MPSV4 (77.4-91.7 vs. 63.1-84.2%, respectively). No safety concerns were identified for either vaccine.

CONCLUSION

MenACYW-TT was well-tolerated and immunogenic in ≥56-year-olds, offering the potential to replace MPSV4 in this age group.

The everchanging epidemiology of meningococcal disease worldwide and the potential for prevention through vaccination

Neisseria meningitidis is a major cause of bacterial meningitis and septicaemia worldwide and is associated with high case fatality rates and serious life-long complications among survivors. Twelve serogroups are recognised, of which six (A, B, C, W, X and Y) are responsible for nearly all cases of invasive meningococcal disease (IMD). The incidence of IMD and responsible serogroups vary widely both geographically and over time. For the first time, effective vaccines against all these serogroups are available or nearing licensure. Over the past two decades, IMD incidence has been declining across most parts of the world through a combination of successful meningococcal immunisation programmes and secular trends. The introduction of meningococcal C conjugate vaccines in the early 2000s was associated with rapid declines in meningococcal C disease, whilst implementation of a meningococcal A conjugate vaccine across the African meningitis belt led to near-elimination of meningococcal A disease. Consequently, other serogroups have become more important causes of IMD. In particular, the emergence of a hypervirulent meningococcal group W clone has led many countries to shift from monovalent meningococcal C to quadrivalent ACWY conjugate vaccines in their national immunisation programmes. Additionally, the recent licensure of two protein-based, broad-spectrum meningococcal B vaccines finally provides protection against the most common group responsible for childhood IMD across Europe and Australia. This review describes global IMD epidemiology across each continent and trends over time, the serogroups responsible for IMD, the impact of meningococcal immunisation programmes and future needs to eliminate this devastating disease.

The epidemiology of invasive meningococcal disease and the utility of vaccination in Malta

Invasive meningococcal disease (IMD) is a vaccine-preventable devastating infection that mainly affects infants, children and adolescents. We describe the population epidemiology of IMD in Malta in order to assess the potential utility of a meningococcal vaccination programme. All cases of microbiologically confirmed IMD in the Maltese population from 2000 to 2017 were analysed to quantify the overall and capsular-specific disease burden. Mean overall crude and age-specific meningococcal incidence rates were calculated to identify the target age groups that would benefit from vaccination. Over the 18-year study period, 111 out of the 245 eligible notified cases were confirmed microbiologically of which 70.3% had septicaemia, 21.6% had meningitis, and 6.3% had both. The mean overall crude incidence rate was 1.49/100,000 population with an overall case fatality rate of 12.6%. Meningococcal capsular groups (Men) B followed by C were the most prevalent with W and Y appearing over the last 6 years. Infants had the highest meningococcal incidence rate of 18.9/100,000 followed by 6.1/100,000 in 1–5 year olds and 3.6/100,000 in 11–15 year old adolescents. The introduction of MenACWY and MenB vaccines on the national immunization schedule in Malta would be expected to reduce the disease burden of meningococcal disease in children and adolescents in Malta.

Immunogenicity and safety of a booster dose of a quadrivalent meningococcal tetanus toxoid-conjugate vaccine (MenACYW-TT) in adolescents and adults: a Phase III randomized study

The quadrivalent meningococcal tetanus toxoid-conjugate vaccine (MenACYW-TT) was assessed as a booster in this Phase III trial (NCT02752906). Quadrivalent meningococcal conjugate vaccine (MCV4)-primed individuals aged ≥15 y (n = 810) were randomized 1:1 to receive a single booster dose of MenACYW-TT (n = 403) or a licensed MCV4 (Menactra®; MCV4-DT [n = 407]). Serum bactericidal antibody assay with human complement (hSBA) was used to measure functional antibodies against serogroups A, C, W, and Y at baseline and Day 30 post-vaccination. Proportions of participants achieving seroresponse (post-vaccination titer ≥1:16 for those with baseline titer <1:8 or ≥4-fold increase in post-vaccination titer for those with baseline titer ≥1:8) were determined. Safety data were collected for 180 d post-vaccination. Non-inferiority of the immune response was demonstrated for MenACYW-TT compared with MCV4-DT based on the proportion of participants achieving hSBA vaccine seroresponse for each of the meningococcal serogroups at Day 30. Moreover, ≥99% of participants in both study groups had hSBA titers ≥1:8 for the four meningococcal serogroups at Day 30. Reactogenicity profiles were comparable between groups. These Phase III data in adolescents and adults show that MenACYW-TT boosts the immune response in those primed with MCV4 vaccines 4–10 y previously, irrespective of whether MCV4-DT or MCV4-CRM was used for priming.

The immunosuppressed traveler: infection risks with autoimmunity and immunosuppression, vaccinations, and general travel advice

The travel-related infection risks in the significantly immunocompromised traveler are complex and comprise vaccine preventable, vector-borne, and other nonvaccine preventable infections. A thorough risk assessment should be performed before travel and advice sought from relevant specialists. Immunosuppression used to treat autoimmune diseases and their mechanisms of action need particular consideration.This risk assessment needs to take the patient's beliefs and preferences into account. It is also important not to neglect noninfectious travel considerations.

Design, synthesis, and structural elucidation of novel NmeNANAS inhibitors for the treatment of meningococcal infection

Neisseria meningitidis is the primary cause of bacterial meningitis in many parts of the world, with considerable mortality rates among neonates and adults. In Saudi Arabia, serious outbreaks of N. meningitidis affecting several hundreds of pilgrims attending Hajj in Makkah were recorded in the 2000–2001 season. Evidence shows increased rates of bacterial resistance to penicillin and other antimicrobial agents that are used in the treatment of the meningococcal disease. The host’s immune system becomes unable to recognize the polysialic acid capsule of the resistant N. meningitidis that mimics the mammalian cell surface. The biosynthetic pathways of sialic acid (i.e., N-acetylneuraminic acid [NANA]) in bacteria, however, are somewhat different from those in mammals. The largest obstacle facing previously identified inhibitors of NANA synthase (NANAS) in N. meningitidis is that these inhibitors feature undesired chemical and pharmacological characteristics. To better comprehend the binding mechanism underlying these inhibitors at the catalytic site of NANAS, we performed molecular modeling studies to uncover essential structural aspects for the ultimate recognition at the catalytic site required for optimal inhibitory activity. Applying two virtual screening candidate molecules and one designed molecule showed promising structural scaffolds. Here, we report ethyl 3-benzoyl-2,7-dimethyl indolizine-1-carboxylate (INLZ) as a novel molecule with high energetic fitness scores at the catalytic site of the NmeNANAS enzyme. INLZ represents a promising scaffold for NmeNANAS enzyme inhibitors, with new prospects for further structural development and activity optimization.

Meningococcal Vaccine for Hajj Pilgrims: Compliance, Predictors, and Barriers

Background: Major intercontinental outbreaks of invasive meningococcal disease associated with the Hajj occurred in 1987, 2000, and 2001. Mandatory meningococcal vaccination for all pilgrims against serogroups A and C and, subsequently, A, C, W, and Y controlled the epidemics. Overseas pilgrims show excellent adherence to the policy; however, vaccine uptake among domestic pilgrims is suboptimal. This survey aimed to evaluate meningococcal vaccine uptake among Hajj pilgrims and to identify key factors affecting this. Methods: An anonymous cross-sectional survey was conducted among pilgrims in Greater Makkah during the Hajj in 2017–2018. Data on socio-demographic characteristics, vaccination status, cost of vaccination, and reasons behind non-receipt of the vaccine were collected. Results: A total of 509 respondents aged 13 to 82 (median 33.8) years participated in the survey: 86% male, 85% domestic pilgrims. Only 389/476 (81.7%) confirmed their meningococcal vaccination status; 64 individuals (13.4%), all domestic pilgrims, did not receive the vaccine, and 23 (4.8%) were unsure. Among overseas pilgrims, 93.5% certainly received the vaccine (6.5% were unsure) compared to 80.9% of domestic pilgrims (p < 0.01). Being employed and having a tertiary qualification were significant predictors of vaccination adherence (odds ratio (OR) = 2.2, 95% confidence interval (CI) = 1.3–3.8, p < 0.01; and OR = 1.7, CI = 1–2.5, p < 0.05, respectively). Those who obtained pre-Hajj health advice were more than three times as likely to be vaccinated than those who did not (OR = 3.3, CI = 1.9–5.9, p < 0.001). Lack of awareness (63.2%, 36/57) and lack of time (15.8%, 9/57) were the most common reasons reported for non-receipt of vaccine. Conclusion: Many domestic pilgrims missed the compulsory meningococcal vaccine; in this regard, lack of awareness is a key barrier. Being an overseas pilgrim (or living at a distance from Makkah), receipt of pre-Hajj health advice, and employment were predictors of greater compliance with the vaccination policy. Opportunities remain to reduce the policy–practice gap among domestic pilgrims.

Uptake of Recommended Vaccines and Its Associated Factors Among Malaysian Pilgrims During Hajj and Umrah 2018

This study aimed to assess the uptake of recommended vaccines and to identify the factors associated with the vaccines' uptake among Malaysian Hajj and Umrah pilgrims. A cross-sectional survey among Malaysian Hajj and Umrah pilgrims in 2018. The uptake of the recommended vaccines was surveyed through an anonymous self-administered questionnaire to pilgrims attending a pre-departure Hajj/Umrah orientation course. Descriptive statistics were used for elaborating the demographic characteristics and vaccines uptake of the respondents. Multiple logistic regression was used for predicting the factors associated with the vaccines' uptake. A total of 1,274 pilgrims participated in the study with a mean age (standard deviation) of 42.42 (15.6). A total of 833 (65.4%) participants were females and 232 of the participants (18.2%) had at least more than one chronic disease. The uptake of influenza and pneumococcal vaccines were 28.6% (364/1,274) and 25.4% (324/1,274), respectively. Among the 527 pilgrims who were "at increased risk" of infections, 168 (31.9%) and 184 (34.9%) received influenza and pneumococcal vaccines, respectively. Gender, marital status and occupation were the common predictors associated with vaccines uptake. The vaccination uptake among Malaysian Hajj and Umrah pilgrims is low and declining from previous years. Educating the pilgrims toward vaccine uptake is essential and exploring the barriers for vaccination.

The 2019 Pan American games: Communicable disease risks and travel medicine advice for visitors to Peru - Recommendations from the Latin American Society for Travel Medicine (SLAMVI)

The next Pan American Games will be held in Peru in the period July-August 2019. Around 6680 participants from 41 countries are expected to take part in the event. There will be a total of 62 sport disciplines. This event poses specific challenges, given its size and the diversity of attendees. Such gatherings also have potential for the transmission of imported or endemic communicable diseases, including measles in view of the global outbreak situation, but also tropical endemic diseases. In anticipation of increased travel, a panel of experts from the Latin American Society for Travel Medicine (SLAMVI) developed the current recommendations taking into consideration the epidemiology and risks of the main communicable diseases at potential destinations in Peru, recommended immunizations and other preventives measures. These recommendations can be used as a basis for advice for travelers and travel medicine practitioners. Mosquito-borne infections also pose a challenge. Although Lima is malaria free, travelers visiting Peruvian high-risk areas for malaria should be assessed regarding the need for chemoprophylaxis. Advice on the correct timing and use of repellents and other personal protection measures is key to preventing vector-borne infections. Other important recommendations for travelers should focus on preventing water- and food-borne diseases including travelers' diarrhea. This paper addresses pre-travel, preventive strategies to reduce the risk of acquiring communicable diseases during the Pan American Games and also reviews the spectrum of endemic infections in Lima and Peru to facilitate the recognition and management of infectious diseases in travelers returning to their countries of origin.

Acquisition of respiratory viruses and presence of respiratory symptoms in French pilgrims during the 2016 Hajj: A prospective cohort study

BACKGROUND

Viral respiratory tract infections are frequent among Hajj pilgrims. However, it is still not known whether viruses are responsible for the symptoms observed in sick pilgrims or whether they only colonize sick and asymptomatic pilgrims.

PATIENTS AND METHODS

A prospective cohort study was conducted among French Hajj pilgrims in 2016. Medical follow-up and systematic nasal swabbing were performed pre- and post-Hajj. Additional samples were obtained per-Hajj, at symptom onset in ill pilgrims. Viruses were identified using the BioFire FilmArray^® Respiratory multiplex qualitative PCR panel.

RESULTS

109 pilgrims were included. 83.5% presented respiratory symptoms during Hajj and 39.5% were still symptomatic on return. 5.5% of pre-Hajj, 95.2% of per-Hajj (at symptom onset) and 46.5% of post-Hajj samples tested positive (p < 0.0001). Acquisition rates of rhinovirus/enterovirus, coronavirus 229E and influenza A virus were respectively 38.6%, 19.8% and 2.0%. Although rhinovirus/enterovirus, coronavirus 229E and influenza A clearance were respectively 70.6%, 71.4% and 100% on return, overall virus carriage proportion on return was 75.0% in pilgrims with influenza-like illness and 44.0% in those who have never experienced this symptoms or resolved it (OR = 4.05, 95% CI [1.02-16.02]).

CONCLUSIONS

Viruses likely play some role in the pathogenesis of the respiratory tract infections at the Hajj. Point of care-rapid multiplex PCR assays are valuable diagnosis tools in this context when used at respiratory symptom onset or soon after.

Tracking a serial killer: Integrating phylogenetic relationships, epidemiology, and geography for two invasive meningococcal disease outbreaks

BACKGROUND

While overall rates of meningococcal disease have been declining in the United States for the past several decades, New York City (NYC) has experienced two serogroup C meningococcal disease outbreaks in 2005-2006 and in 2010-2013. The outbreaks were centered within drug use and sexual networks, were difficult to control, and required vaccine campaigns.

METHODS

Whole Genome Sequencing (WGS) was used to analyze preserved meningococcal isolates collected before and during the two outbreaks. We integrated and analyzed epidemiologic, geographic, and genomic data to better understand transmission networks among patients. Betweenness centrality was used as a metric to understand the most important geographic nodes in the transmission networks. Comparative genomics was used to identify genes associated with the outbreaks.

RESULTS

Neisseria meningitidis serogroup C (ST11/ET-37) was responsible for both outbreaks with each outbreak having distinct phylogenetic clusters. WGS did identify some misclassifications of isolates that were more distant from the outbreak strains, as well as those that should have been included based on high genomic similarity. Genomes for the second outbreak were more similar than the first and no polymorphism was found to either be unique or specific to either outbreak lineage. Betweenness centrality as applied to transmission networks based on phylogenetic analysis demonstrated that the outbreaks were transmitted within focal communities in NYC with few transmission events to other locations.

CONCLUSIONS

Neisseria meningitidis is an ever changing pathogen and comparative genomic analyses can help elucidate how it spreads geographically to facilitate targeted interventions to interrupt transmission.

Infectious Diseases and Mass Gatherings

Purpose of Review

Mass gatherings (MGs) are characterized by a high concentration of people at a specific time and location. Infectious diseases are of particular concern at MGs. The aim of this review was to summarize findings in the field of infectious diseases with a variety of pathogens associated with international MGs in the last 5 years.

Recent Findings

In the context of Hajj, one of the largest religious MGs at Mecca, Saudi Arabia, respiratory tract infections are the leading cause of infectious diseases in pilgrims with a prevalence of 50–93%. The most commonly acquired respiratory viruses were human rhinovirus, followed by human coronaviruses and influenza A virus, in decreasing order. Haemophilus influenzae, Staphylococcus aureus, and Streptococcus pneumoniae were the predominant bacteria. The prevalence of Hajj-related diarrhea ranged from 1.1 to 23.3% and etiologies included Salmonella spp., and Escherichia coli, with evidence of acquisition of antimicrobial-resistant bacteria. In other MGs such as Muslim, Christian, and Hindu religious events, sports events, and large-scale open-air festivals, outbreaks have been reported less frequently. The most common outbreaks at these events involved diseases preventable by vaccination, notably measles and influenza. Gastrointestinal infections caused by a variety of pathogens were also recorded.

Summary

Because social distancing and contact avoidance are difficult measures to implement in the context of many MGs, individual preventive measures including vaccination, use of face mask, disposable handkerchief and hand hygiene may be recommended. Nevertheless, the effectiveness of these measures has been poorly investigated in the context of MGs.