Serogroup B meningococcal disease during Hajj: Preparing for the worst scenario

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.

Meningococcal disease during the Hajj and Umrah mass gatherings

The Hajj and Umrah religious mass gatherings hosted by the Kingdom of Saudi Arabia can facilitate the transmission of infectious diseases. The pilgrimages have been associated with a number of local and international outbreaks of meningococcal disease. These include serogroup A disease outbreaks in 1987 and throughout the 1990s and two international serogroup W135 outbreaks in 2000 and 2001. The implementation of strict preventative measures including mandatory quadrivalent meningococcal vaccination and antibiotic chemoprophylaxis for pilgrims from the African meningitis belt has prevented pilgrimage-associated meningococcal outbreaks since 2001. However, the fluid epidemiology of the disease and the possibility of outbreaks caused by serogroups not covered by the vaccine or emerging hyper-virulent strains, mean that the disease remains a serious public health threat during these events. Continuous surveillance of carriage state and the epidemiology of the disease in the Kingdom and globally and the introduction of preventative measures that provide broad and long-lasting immunity and impact carriage are warranted.

Prevention of meningococcal disease during the Hajj and Umrah mass gatherings: past and current measures and future prospects

The Kingdom of Saudi Arabia (KSA) has a long history of instituting preventative measures against meningococcal disease (MD). KSA is at risk of outbreaks of MD due to its geographic location, demography, and especially because it hosts the annual Hajj and Umrah mass gatherings. Preventative measures for Hajj and Umrah include vaccination, targeted chemoprophylaxis, health awareness and educational campaigns, as well as an active disease surveillance and response system. Preventative measures have been introduced and updated in accordance with changes in the epidemiology of MD and available preventative tools. The mandatory meningococcal vaccination policy for pilgrims has possibly been the major factor in preventing outbreaks during the pilgrimages. The policy of chemoprophylaxis for all pilgrims arriving from the African meningitis belt has also probably been important in reducing the carriage and transmission of Neisseria meningitidis in KSA and beyond. The preventative measures for Hajj and Umrah are likely to continue to focus on vaccination, but to favour the conjugate vaccine for its extra benefits over the polysaccharide vaccines. Additionally, the surveillance system will continue to be strengthened to ensure early detection and response to cases and outbreaks; ongoing disease awareness campaigns for pilgrims will continue, as will chemoprophylaxis for target groups. Local and worldwide surveillance of the disease and drug-resistant N. meningitidis are crucial in informing future recommendations for vaccination, chemoprophylaxis, and treatment. Preventative measures should be reviewed regularly and updated accordingly, and compliance with these measures should be monitored and enhanced to prevent MD during Hajj and Umrah, as well as local and international outbreaks.

Burden of vaccine preventable diseases at large events

BACKGROUND

Large events or mass gatherings (MGs) are known to amplify the risk of infectious diseases, many of which can be prevented by vaccination. In this review we have evaluated the burden of vaccine preventable diseases (VPDs) in MGs.

METHODS

Major databases like PubMed and Embase, Google Scholar and pertinent websites were searched by using MeSH terms and text words; this was supplemented by hand searching. Following data abstraction, the pooled estimate of the burden of VPDs was calculated when possible; otherwise a narrative synthesis was conducted.

RESULTS

In the past, at religious MGs like Hajj and Kumbh Mela, cholera caused explosive outbreaks; but currently respiratory infections, notably influenza, are the commonest diseases not only at Hajj but also at World Youth Day and Winter Olympiad. The recent cumulative attack rate of influenza at Hajj is 8.7% (range 0.7-15.8%), and the cumulative prevalence is 3.6% (range: 0.3-38%). Small outbreaks of measles (13-42 cases per event) have been reported at sport, entertainment and religious events. A sizeable outbreak (>200 cases) was reported following a special Easter Festival in Austria. An outbreak of hepatitis A occurred following the 'Jam bands' music festival. Other VPDs including pneumococcal disease, pertussis and tuberculosis have been reported in relation to MG attendance.

CONCLUSION

VPDs not only affect the participants of MGs but also their contacts; vaccine uptake is variable and vaccine implementation is likely to have beneficial effects. Research to address the knowledge gaps surrounding VPDs at MGs is needed.

Trends and variations in the epidemiology of meningococcal disease in Kuwait 1987-2013

The introduction of Haemophilus influenzae type b (Hib) conjugate vaccine and conjugate pneumococcal vaccine into routine childhood vaccination in Kuwait has resulted in the emergence of Neisseria meningitidis as the leading cause of invasive bacterial infection in children. Currently, a quadrivalent ACYW-135 meningococcal polysaccharide vaccine is administered as part of routine childhood vaccination in Kuwait at the age of 2 years. Conjugate meningococcal vaccines have been shown to be more effective in preventing meningococcal infection in young children. The objective of this study was to describe the epidemiology of meningococcal disease (MD) in Kuwait and evaluate the need for conjugate vaccine in routine childhood immunization. We have reviewed the MD surveillance data from the communicable disease unit, Ministry of Health, Kuwait during the period from 1987 to 2013. The analysis included microbiologically confirmed cases of N. meningitidis in the blood and cerebrospinal fluid. There were 293 cases of confirmed MD during the study period. Two hundred and four cases (70%) were in children ≤ 14 years of age. The mean incidence rate was 0.5/100,000 persons. The dominant serogroups were W-135 and B, accounting for 80 cases (32%) each. Serogroup B accounted for 69/204 (34%) of all cases in children ≤ 14 years and serogroup A accounted for 36/89 40% of all adult cases. There were three outbreaks: 1987 (caused by serogroup A), 1989 (caused by serogroup W-135) and 2002 (caused by serogroup B). The mean case fatality rate was 13.5%. In conclusion, despite childhood routine vaccination with ACYW-135 polysaccharide vaccine, infants and young children remain at high risk for MD, which supports the introduction of conjugate meningococcal vaccine to the routine childhood vaccination schedule.

Safety and immunogenicity of a meningococcal quadrivalent conjugate vaccine in five- to eight-year-old Saudi Arabian children previously vaccinated with two doses of a meningococcal quadrivalent polysaccharide vaccine

Saudi Arabian children respond poorly to 2 doses of meningococcal quadrivalent polysaccharide vaccine (MPSV4) when given before 2 years of age. This study examined whether such children were able to respond to 1 dose of quadrivalent meningococcal diphtheria toxoid conjugate vaccine (MCV4) when they were older. Saudi Arabian children 5 to 8 years of age who had previously been vaccinated with 2 doses of MPSV4 when they were under 2 years of age (termed the prior-MPSV4 group) were enrolled in a controlled, open-label, multicenter study. In the prior-MPSV4 group, children (n = 153) received 1 dose of MCV4, as did a group of age-matched meningococcal vaccine-naïve children (n = 85). Blood samples collected prevaccination and 28 days postvaccination were measured for serogroup-specific serum bactericidal antibody (SBA) levels in the presence of baby rabbit complement (rSBA) and for IgG antibody levels. Vaccine tolerability and safety were also evaluated. For all of the measured serogroups (A, C, Y, and W-135), the meningococcal vaccine-naïve participants achieved higher postvaccination rSBA geometric mean titers (GMTs) than did those in the prior-MPSV4 group. This was statistically significant for serogroup C (512 versus 167). Percentages of participants with postvaccination titers of ≥8 and with ≥4-fold increases in prevaccination to postvaccination titers appeared to be quite similar in the 2 groups. No worrisome safety signals were detected. MCV4 induced robust immune responses and was well tolerated in Saudi Arabian children who previously received 2 doses of MPSV4 as well as in those who were previously meningococcal vaccine naïve.

Meningococcal disease in the Middle East and North Africa: an important public health consideration that requires further attention

This paper reviews the epidemiological data describing meningococcal disease in the Middle East and North Africa (MENA). While meningococcal disease remains an important cause of endemic and epidemic disease in many MENA countries, existing published epidemiological data appear limited, fragmented, and collected via disparate methodologies. Children aged 5 years and younger are predominantly affected, though outbreaks of the disease often affect older age groups. Whilst serogroup A remains a main cause of meningococcal disease in the region, cases of serogroup B, W-135, and Y have been increasingly reported over the last two decades in some countries. The Hajj pilgrimage is a key factor influencing outbreaks and transmission, and the use of vaccines has minimized the effects on the home countries of the pilgrims and has decreased global dissemination of disease. Wider use of available polyvalent meningococcal conjugate vaccines may provide broader protection against the range of serogroups causing disease or posing a threat in the region. In addition, strengthening regional surveillance systems and regularly publishing reports with reliable estimates of disease incidence, carriage, disease-related mortality, and sequelae may facilitate the development of appropriate interventions and public health strategies regarding meningococcal disease within the region.

Consensus recommendation for meningococcal disease prevention in children and adolescents in the Middle East region

Facing the availability of the new generation of quadrivalent meningococcal conjugate vaccines (Menveo®, Menactra® and others pending for license) and their recent implementation in Saudi Arabia, experts from 11 countries of the Middle East region met at a “Meningococcal Leadership Forum” (MLF), which took place in May 2010 in Dubai. The participants of the conference discussed the importance of introducing the concept of conjugate vaccines – especially for children and adolescents – and elaborated a consensus recommendation to support healthcare professionals and decision makers with their expertise. In experts’ opinion, conjugate vaccines are the best choice for the prevention of meningococcal disease caused by serogroups A, C, W-135 and Y. As quadrivalent meningococcal conjugate vaccines are registered and available in the Middle East region, they should replace plain polysaccharide vaccines and be integrated in pediatric and adolescent vaccination schedules, including infant vaccination concomitantly with basic EPI vaccines when licensed.

Consensus building and recommendations based on the available epidemiology of meningococcal disease in Gulf Cooperation Council States

The Gulf Cooperation Council (GCC) States share concerns about meningococcal disease, particularly in association with the Hajj and Umrah pilgrimages, which have been connected with outbreaks within the Kingdom of Saudi Arabia and among contacts of the pilgrims in their countries of origin. Currently, the most prevalent meningococcal serogroup in the GCC States is W-135. Although vaccination with polysaccharide vaccines has protected pilgrims and their close contacts from invasive disease, the potential availability of novel conjugate vaccines, such as the one currently used for vaccination of military personnel in the Kingdom of Saudi Arabia, prompted an evaluation of disease epidemiology in the region. For several countries, published data on recent epidemiology are not available. We report findings from a meeting of the GCC States Meningitis Study Group, which comprised experts from the Kingdom of Saudi Arabia, the Kingdom of Bahrain, Kuwait, Qatar, the Sultanate of Oman, and the United Arab Emirates. These experts provided an update on epidemiology and current vaccination practices in the GCC States, and discussed new approaches to more effective disease prevention.