Carriage of Neisseria meningitidis in the Hajj and Umrah mass gatherings

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.

Proceedings of the Expert Consensus Group meeting on meningococcal serogroup B disease burden and prevention in India

Meningococcal disease is highly transmissible, life-threatening and leaves significant sequelae in survivors. Every year, India, which has a plethora of risk factors for meningococcal disease, reports around 3000 endemic cases. However, the overall disease burden and serogroup distribution are unknown, creating a setting of general disease negligence and unawareness. Vaccination with quadrivalent meningococcal conjugate vaccine A, C, W, and Y is only recommended for high-risk children, and there is no overall guidance for meningococcal serogroup B (MenB) vaccination. MenB vaccines, which recently have been licensed in many countries but not in India, have significantly aided the fight against meningococcal disease. However, these MenB vaccines are not available in India. An Expert Consensus Group meeting was held with leading meningococcal disease experts to better understand the current disease epidemiology, particularly serogroup B, the prevalence gaps, and feasible ways to bridge them. The proceedings are presented in this paper.

Neisseria meningitidis carriage rate, antibiotic susceptibility profile, and associated factors among prisoners at Jimma zonal correction facility in Jimma Town, Southwestern Ethiopia: a cross-sectional study

Background

Neisseria meningitidis causes severe life-threatening meningococcal disease with a case fatality rate of 10–15% even with proper treatment. In Ethiopia, particularly in our study area, inadequate information is found on meningococcal disease. So, this study aimed to assess N. meningitidis carriage rate, antibiotic susceptibility profile, and associated factors among prisoners in Jimma Town, Southwestern Ethiopia.

Methods

A cross-sectional study was conducted in Jimma town, Southwest Ethiopia, from May to October 2019. A stratified sampling technique was used and proportional allocation was done. A total of 550 oropharyngeal swabs were collected, processed, isolated, and identified N. meningitidis using standard microbiological techniques. Antibiotics susceptibility test was done for isolates using the disk diffusion method. Data on demographic and associated factors for carriage were collected using a structured questionnaire. Data were summarized using frequency, percentage, graph, and table. A logistic regression model was used to see the association between the dependent and independent variables. Variables with a p-value < 0.25 during bivariate analysis were included in multivariate analysis to identify factors significantly associated with the meningococcal carriage and, a p-value < 0.05 was considered statistically significant.

Result

Out of the 550 study participants, 76(13.8%) with (CI: 7.20–18.20) were found carriers of N meningitidis. The predominant isolates were non-serogroupable 26(34.2%) and serogroup W/Y 22(28.9%), respectively. N. meningitidis isolates showed highest sensitivity to chloramphenicol 74(97.4%). Meningococcal carriage rate was significantly associated with being age group of 16–20 years; having respiratory symptoms within 3 months and active cigarette smoking within 3 months.

Conclusions

The majority of participants harbor most of the serogroups responsible for invasive cases of meningococcal disease. Respiratory symptoms, active cigarette smoking, and age group of 16–20 years increased the risk of N. meningitidis pharyngeal carriage rate. This study suggests providing better health education to control respiratory symptoms, smoking, and providing antibiotic prophylaxis for prisoners.

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.

The AmiC/NlpD pathway dominates peptidoglycan breakdown in Neisseria meningitidis and affects cell separation, NOD1 agonist production, and infection

The human-restricted pathogen Neisseria meningitidis, which is best known for causing invasive meningococcal disease, has a nonpathogenic lifestyle as an asymptomatic colonizer of the human naso- and oropharyngeal space. N. meningitidis releases small peptidoglycan (PG) fragments during growth. It was demonstrated previously that N. meningitidis releases low levels of tripeptide PG monomer, which is an inflammatory molecule recognized by the human intracellular innate immune receptor NOD1. In this present study, we demonstrated that N. meningitidis released more PG-derived peptides compared to PG monomers. Using a reporter cell line overexpressing human NOD1, we showed that N. meningitidis activates NOD1 using PG-derived peptides. Generation of such peptides required the presence of the periplasmic N-acetylmuramyl-L-alanine amidase AmiC, and the outer membrane lipoprotein, NlpD. AmiC and NlpD were found to function in cell separation, and mutation of either amiC or nlpD resulted in large clumps of unseparated N. meningitidis cells instead of the characteristic diplococci. Using stochastic optical reconstruction microscopy, we demonstrated that FLAG epitope-tagged NlpD localized to the septum, while similarly-tagged AmiC was found at the septum in some diplococci but distributed around the cell in most cases. In a human whole blood infection assay, an nlpD mutant was severely attenuated and showed particular sensitivity to complement. Thus, in N. meningitidis the cell separation proteins AmiC and NlpD are necessary for NOD1 stimulation and for survival during infection of human blood.

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.

Meningococcal disease surveillance in the Asia-Pacific region (2020): The global meningococcal initiative

The degree of surveillance data and control strategies for invasive meningococcal disease (IMD) varies across the Asia-Pacific region. IMD cases are often reported throughout the region, but the disease is not notifiable in some countries, including Myanmar, Bangladesh and Malaysia. Although there remains a paucity of data from many countries, specific nations have introduced additional surveillance measures. The incidence of IMD is low and similar across the represented countries (<0.2 cases per 100,000 persons per year), with the predominant serogroups of Neisseria meningitidis being B, W and Y, although serogroups A and X are present in some areas. Resistance to ciprofloxacin is also of concern, with the close monitoring of antibiotic-resistant clonal complexes (e.g., cc4821) being a priority. Meningococcal vaccination is only included in a few National Immunization Programs, but is recommended for high-risk groups, including travellers (such as pilgrims) and people with complement deficiencies or human immunodeficiency virus (HIV). Both polysaccharide and conjugate vaccines form part of recommendations. However, cost and misconceptions remain limiting factors in vaccine uptake, despite conjugate vaccines preventing the acquisition of carriage.

A Comprehensive Review of Meningococcal Disease Burden in India

INTRODUCTION

Meningococcal disease caused by Neisseria meningitidis has a high case fatality rate. Of 12 distinct serogroups, A, B, C, W-135 (W) and Y cause the majority of infections. The meningococcal disease burden and epidemiology in India are not reliably known. Hence, we performed a narrative review with a systematically conducted search to summarize information on meningococcal disease burden and epidemiology and vaccination recommendations for meningococcal disease in India.

METHODS

A search of Medline and Embase databases was undertaken to identify relevant publications published in the last 25 years.

RESULTS

Results from 32 original publications, 11 of which were case reports, suggest a significant burden of meningococcal disease and related complications. Meningococcal disease is increasingly reported among adolescents and adults, and large outbreaks have been reported in this population. Meningococcal disease in India is caused almost exclusively by serogroup A; serogroups B, C, W and Y have also been documented. Meningococcal disease burden data remain unreliable because of limited disease surveillance, insufficient laboratory capacity, misdiagnosis and prevalence of extensive antibiotic use in India. Lack of access to healthcare also increases under-reporting, thus bringing the reliability of the data into question. Conjugate meningococcal vaccines are being used for disease prevention by national governments and immunization programs globally. In India, meningococcal vaccination is recommended only for certain high-risk groups, during outbreaks and for international travelers such as Hajj pilgrims and students pursuing studies abroad.

CONCLUSION

Meningococcal disease is prevalent in India but remains grossly underestimated and under-reported. Available literature largely presents outbreak data related to serogroup A disease; however, non-A serogroup disease cases have been reported. Reliable epidemiologic data are urgently needed to inform the true burden of endemic disease. Further research into the significance of meningococcal disease burden can be used to improve public health policy in India. Fig. 1 Plain language summary.

Genotypic characterization and genome comparison reveal insights into potential vaccine coverage and genealogy of Neisseria meningitidis in military camps in Vietnam

Background

Neisseria meningitidis remains the main cause of sporadic meningitis and sepsis in military camps in Vietnam. Yet, very limited molecular data of their genotypic and epidemiological characteristics are available from Vietnam, and particularly the military environment. Whole genome sequencing (WGS) has proven useful for meningococcal disease surveillance and guiding preventative vaccination programs. Previously, we characterized key genetic and epidemiological features of an invasive N. meningitidis B isolate from a military unit in Vietnam. Here, we extend these findings by sequencing two additional invasive N. meningitidis B isolated from cerebrospinal fluid (CSF) of two meningitis cases at another military unit and compared their genomic sequences and features. We also report the sequence types and antigenic profiles of 25 historical and more recently emerged N. meningitidis isolates from these units and other units in proximity.

Methods

Strains were sequenced using the Illumina HiSeq platform, de novo assembled and annotated. Genomes were compared within and between military units, as well as against the global N. meningitidis collection and other isolates from the Southeast Asia region using PubMLST. Variations at the nucleotide level were determined, and phylogenetic relationships were estimated. Antigenic genotypes and vaccine coverage were analyzed using gMATS and PubMLST. Susceptibility of isolates against commonly used antibiotic agents was examined using E-test.

Results

Genome comparison revealed a high level of similarity among isolates both within and between units. All isolates showed resistance to chloramphenicol and carried identical catP gene with other Southeast Asian isolates, suggesting a common lineage. Their antigenic genotypes predicted no coverage by either Bexsero^®or Trumenba^®, and nucleotide variation analysis revealed diverse new, unassigned alleles at multiple virulence loci of all strains. Groups of singleton and unique novel sequence types extending beyond individual camps were found from epidemiological data of 25 other isolates. Our results add to the sparse published molecular data of N. meningitidis in the military units in Vietnam, highlight their diversity, distinct genetic features and antibiotic resistance pattern, and emphasize the need for further studies on the molecular characteristics of N. meningitidis in Vietnam.

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.

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.

Mass Gatherings

A mass gathering is “any occasion, either organized or spontaneous, that attracts sufficient numbers of people to strain the planning and response resources of the community, city, or nation hosting the event.”² Often the existing infrastructure (e.g., public health, health care, or emergency services) is inadequate for the disproportionate sudden surge in demand, hence careful planning is required. Although infectious diseases are most feared due to the potential for rapid international spread, noncommunicable diseases, accidents, and stampedes are more frequent. Mass gatherings may lead to three potential infectious disease public health threats: the risk of importation of infectious diseases usually not seen in the country of the gathering; the amplification of transmission during the event; and the international spread of infectious disease through global mobility networks.

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Mass gatherings are the temporary collection of large numbers of people at one site or location for a common purpose.

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Mass gatherings present some of the most complex management challenges faced by governments and organizers.

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Mass gatherings may lead to three potential infectious disease public health threats: the risk of importation of infectious diseases usually not seen in the country of the gathering; the amplification of transmission during the event; and the international spread of infectious disease through global mobility networks.

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While infectious diseases may be of greater global public health relevance, noncommunicable diseases, accidents, and stampede usually have a higher local impact with respect to morbidity and mortality during mass gatherings.

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.

Meningococcal disease burden and transmission in crowded settings and mass gatherings other than Hajj/Umrah: A systematic review

BACKGROUND

Mass gatherings (MGs) such as the Hajj and Umrah pilgrimages are known to amplify the risk of invasive meningococcal disease (IMD) due to enhanced transmission of the organism between attendees. The burden of IMD at MGs other than Hajj and Umrah has not previously been quantified through a systematic review.

METHODS

A systematic search for relevant articles in PubMed and Embase was conducted using MeSH terms; this was buttressed by hand searching. Following data abstraction, a narrative synthesis was conducted to quantify the burden of IMD at MGs and identify potential risk factors and mitigation measures.

RESULTS

Thirteen studies reporting occurrence of IMD at MGs or similar crowded settings were identified. Eight studies reported cases or outbreaks in MGs of ≥1000 people; five others reported IMD in other crowded settings; all occurred between 1991 and 2015. All age groups were involved in the identified studies; however the majority of cases (∼80%) were young people aged 15-24 years. The number of affected people ranged from one to 321 cases and the overall crude estimate of incidence was calculated as 66 per 100,000 individuals. Serogroups A, C, B and W were identified, with serogroups A and C being most common. Of 450 cases of IMD reported in non-Hajj/Umrah MGs, 67 (14.9%) had fatal outcomes.

CONCLUSION

IMD outbreaks at non-Hajj/Umrah MGs are generally much smaller than Hajj-related outbreaks and affect mainly young people. Health education and vaccination should be considered for attendees of high risk non-Hajj/Umrah MGs, especially those involving adolescents and young adults.

Prevention of meningococcal disease at mass gatherings: Lessons from the Hajj and Umrah

Meningococcal disease is a serious public health threat given the seriousness of the illness, its disabling sequelae and its potential for epidemic spread. The disease is a concern during mass gatherings which provide conditions that facilitate transmission of infectious agents including Neisseria meningitidis. Implementation of appropriate meningococcal disease preventive measures during at-risk mass gatherings is crucial to prevent illness and outbreaks which may result in significant morbidity and mortality as well as local and international spread of the disease. These preventive measures should be informed by comprehensive risk assessments of the disease at those events and may include the use of vaccination, chemoprophylaxis and health awareness and educational campaigns, supported by efficient disease surveillance and response systems. The Hajj and Umrah religious mass gatherings in the Kingdom of Saudi Arabia are examples of how the implementation of such preventive measures was successful in reducing the incidence of meningococcal disease during these events as well as controlling and preventing outbreaks. Lessons learned from the Hajj and Umrah experience can inform meningococcal disease preventive strategies for other mass gatherings worldwide.

Vaccination strategies for the prevention of meningococcal disease

Routine prophylactic vaccination and mass vaccination strategies have been used to control both endemic and epidemic disease caused by Neisseria meningitidis globally. This review discusses real-world examples of these vaccination strategies, their implementation, and outcomes of these efforts, with the overall goal of providing insights on how to achieve optimal control of meningococcal disease through vaccination in varied settings. Tailoring immunization programs to fit the needs of the target population has the potential to optimally reduce disease incidence.

Increase of Neisseria meningitidis W:cc11 invasive disease in Chile has no correlation with carriage in adolescents

Neisseria meningitidis is a human exclusive pathogen that can lead to invasive meningococcal disease or may be carried in the upper respiratory tract without symptoms. The relationship between carriage and disease remains poorly understood but it is widely accepted that decreasing carriage by immunization should lead to a reduction of invasive cases. Latin America has experienced an increased incidence of serogroup W invasive cases of Neisseria meningitidis in the last decade. Specifically in Chile, despite low total incidence of invasive cases, serogroup W has become predominant since 2011 and has been associated with elevated mortality. Expecting to gain insight into the epidemiology of this disease, this study has used molecular typing schemes to compare Neisseria meningitidis isolates causing invasive disease with those isolates collected from adolescent carriers during the same period in Chile. A lower carriage of the serogroup W clonal complex ST-11/ET37 than expected was found; whereas, the same clonal complex accounted for 66% of total invasive meningococcal disease cases in the country that year. A high diversity of PorA variable regions and fHbp peptides was also ascertained in the carrier isolates compared to the invasive ones. According to the results shown here, the elevated number of serogroup W invasive cases in our country cannot be explained by a rise of carriage of pathogenic isolates. Overall, this study supports the idea that some strains, as W:cc11 found in Chile, possess an enhanced virulence to invade the host. Notwithstanding hypervirulence, this strain has not caused an epidemic in Chile. Finally, as genetic transfer occurs often, close surveillance of Neisseria meningitidis strains causing disease, and particularly hypervirulent W:cc11, should be kept as a priority in our country, in order to prepare the best response to face genetic changes that could lead to enhanced fitness of this pathogen.

Protecting UK adolescents and adults against meningococcal serogroup B disease

INTRODUCTION

Meningococcal serogroup B disease (MenB) is endemic in the UK and continues to cause the majority of invasive meningococcal disease. Two broadly protective protein-based MenB vaccines are now licensed and available, both with wide age indications. Whilst the UK recently became the first country to routinely vaccinate infants against MenB, a recommendation has not yet been extended to older age groups who can also now benefit from these vaccines.

AREAS COVERED

This review summarizes the evidence supporting the rationale for adolescents and adults in the UK to consider MenB vaccination.

EXPERT COMMENTARY

Although MenB disease is rare, the UK reports one of the highest annual incidence rates within the European region, with over a third of cases occurring in those aged 10+ years. Overall, the case fatality rate following MenB disease in the UK is 4.2% but can be more than twice as high in teenagers and adults than in infants, and survivors are often left with life-changing disabling sequelae. MenB outbreaks are unpredictable and continue to occur in regions where it is endemic. These outbreaks often affect students attending school or university, with living on a campus being an important risk factor. Concerned individuals in this age group should consider MenB vaccination.

Neisseria meningitidis nasopharyngeal carriage during the Hajj: A cohort study evaluating the need for ciprofloxacin prophylaxis

BACKGROUND

The annual Muslim pilgrimage has the potential of increase risk for acquisition of Neisseria meningitidis. Here, we evaluate the Hajj impact on the prevalence of N. meningitidis carriage in a paired and non-paired cohort of pilgrims. Secondary objectives were to calculate the compliance with recommended vaccination.

METHODS

This is a prospective paired (arriving and departing), non-paired arriving and non-paired departing cohort study with the collection of nasopharyngeal samples at the start and the end of the Hajj.

RESULTS

The study included unpaired arriving pilgrims at King Abdul Aziz International Airport (N=1055), unpaired departing cohort (N=373), and a paired cohort (N=628) who were tested on arrival and departure. Meningococcal vaccination was received by all pilgrims, 98.2% received quadrivalent polysaccharide vaccine (ACWY), and 1.8% received meningococcal quadrivalent conjugate vaccine (MCV4). Only 1.61% and 23.03% received pneumococcal and influenza vaccines, respectively. Of the 1055 arriving unpaired pilgrim, 36 (3.4%) tested positive for nasopharyngeal carriage of N. meningitidis, and 24 (66.7%) of these were serogroup B, the remainder were non-groupable. Haemophilus influenza was detected among 45 (4.3%), and 11 (1%) carriers were positive for both N. meningitidis and H. influenzae. Out of 373 in the unpaired departing cohort, 6 (1.61%) tested positive for N. meningitidis, and 34 (9.1%) were positive for H. influenzae. Of the 628 paired cohort pilgrims, 36 (5.7%) pilgrims were positive for N. meningitidis at arrival and 16 (2.5%) pilgrims were positive after the hajj.

CONCLUSION

This the largest study of the epidemiology of N. meningitidis among pilgrims. The study showed a significant difference in the carriage between pilgrims from high endemicity and other pilgrims with a predominance of serogroup B. The continued use of ciprofloxacin as prophylactic antibiotics should be reconsidered as well as the consideration to add serogroup B as a required vaccination.

What is the experience from previous mass gathering events? Lessons for Zika virus and the Olympics 2016

All previous experiences from different mass gathering show that vaccine preventable diseases is the most important infections like influemza, hepatitis A, polio and meningitis. Three mass gathering held in Africa during the Ebola outbreak accepted participants from West Africa and was able to handle the theoretical risk without any incident. Therefore we believe that the Olympc games in Rio de Janeiro should not be canceled. The number of visitors to the games is a tine fraction (1%) of other visitors to Zika endemic con tries and it will have no measurable effect on the risk of spreading Zika virus, if the games was cancelled.