Scholarly article on topic 'Meningococcal disease during the Hajj and Umrah mass gatherings'

Meningococcal disease during the Hajj and Umrah mass gatherings Academic research paper on "Clinical medicine"

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Abstract of research paper on Clinical medicine, author of scientific article — Saber Yezli, Abdullah M. Assiri, Rafat F. Alhakeem, Abdulhafiz M. Turkistani, Badriah Alotaibi

Summary 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.

Academic research paper on topic "Meningococcal disease during the Hajj and Umrah mass gatherings"

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International Journal of Infectious Diseases

journal homepage www.elsevier.com/locate/ijid

Meningococcal disease during the Hajj and Umrah mass gatherings

Saber Yezlia'*, Abdullah M. Assirib, Rafat F. Alhakeemb, Abdulhafiz M. Turkistanic, Badriah Alotaibia

a The Global Centre for Mass Gatherings Medicine, Public Health Directorate, Ministry of Health, Riyadh, Saudi Arabia b Public Health Directorate, Ministry of Health, Riyadh, Saudi Arabia c Makkah Regional Health Affairs, Ministry of Health, Jeddah, Saudi Arabia

ARTICLE INFO

SUMMARY

Article history:

Received 17 November 2015 Received in revised form 17 March 2016 Accepted 3 April 2016 Corresponding Editor: Eskild Petersen, Aarhus, Denmark.

Keywords:

Mass gathering Meningococcal disease Meningitis Outbreak

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.

© 2016 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-

nc-nd/4.0/).

1. Introduction

Neisseria meningitidis is a Gram-negative, oxidase-positive, aerobic diplococcus of the family Neisseriaceae. It is an exclusive human pathogen, carried asymptomatically in the nasopharynx by about 10% of the general population in non-epidemic periods.1 The bacterium can be either structurally encapsulated or not encapsulated. Capsule polysaccharide expression plays a key role in meningococcal pathogenesis and is the basis for the major serogrouping. In total, 13 serogroups of N. meningitidis have been reported, but only six serogroups (A, B, C, W135, X, and Y) cause almost all invasive meningococcal disease worldwide.2,3 N. meningitidis strains that cause invasive disease are almost always encapsulated, which helps the survival of the bacteria during invasive disease and promotes transmission, as well as protection from antibodies and phagocytic cells.3

Meningococci are spread from person to person through direct contact with oropharyngeal secretions, and asymptomatic carriers are the primary source of N. meningitidis transmissions.1 However, less than 1% of individuals who acquire carriage go on to develop

* Corresponding author. Tel.: +96611401555 ext. 1863. E-mail address: saber.yezli@gmail.com (S. Yezli).

meningococcal disease.4 The balance between carriage of the organism and the development of the disease after acquisition is affected by N. meningitidis characteristics such as bacterial virulence factors and host and environmental factors including age, functional or anatomic asplenia, and host immune defense mechanisms.4,5

Human infections with N. meningitidis remain a serious health problem; 500 000 to 1.2 million people are infected and between 50 000 and 135 000 die per year worldwide.6 Infections present as a spectrum of clinical illness, with meningitis (in 80-85%of cases) and septicemia being the most common. Less common presentations include pneumonia, septic arthritis, pericarditis, conjunctivitis, and urethritis.4,7 Even with appropriate treatment, the case fatality rate is high: 10-40% depending on manifestation, age, and serogroup.3,8 Among survivors, up to 20% suffer from complications and sequelae of meningococcal infection, including cognitive deficits, bilateral hearing loss, motor deficits, seizures, visual impairment, hydro-cephalus, and loss of limbs due to tissue necrosis.4

2. The global epidemiology of meningococcal disease

A notable feature of the meningococcus is its fluid epidemiology. There are substantial cyclical fluctuations in meningococcal disease

http://dx.doi.org/10.1016/j.ijid.2016.04.007

1201-9712/© 2016 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

incidence and the occurrence of outbreaks and epidemics worldwide. Disease patterns and incidence vary in populations geographically and over time, among the different invasive meningococcal serogroups and sequence type clonal complexes.2 The majority of countries in the high-incidence group are found in the African meningitis belt, while many moderate-incidence countries are found in the European and African regions and Australia; low-incidence countries include many from Europe and the Americas.9 By far the highest incidence of meningococcal disease occurs in the meningitis belt of Sub-Saharan Africa, extending from Senegal in the west to Ethiopia in the east. During epidemics, the incidence can reach 1000 cases per 100 000, or 1% of the population.2 Serogroup A has been the most important serogroup in this region.2,3 However, serogroup W135 has also been an important cause of more recent outbreaks. Serogroup C is responsible for smaller more historical outbreaks and there is recent evidence that serogroup X may now be emerging in the region.9-11 The introduction of the newly developed meningococcal A conjugate vaccine in countries of the African meningitis belt since 2010 is thought to be responsible for a reduced case load and epidemic activity in the region in recent years, with expected elimination of epidemics caused by serogroup A.12,13 However, recent outbreaks of the disease in the region, including the outbreak in Niger in 2015, the largest meningitis outbreak caused by serogroup C in the African meningitis belt, show that the disease remains a serious public health threat in the region.13 In the Americas, the reported incidence of meningococcal disease is in the range of 0.3-4 cases per 100 000 population, with some countries such as the USA currently having incidence at a historical low.2 Most of the disease in the Americas is caused by serogroups C and B, although serogroup Y causes a substantial proportion of infections in some countries and W135 is emerging.9

In European countries, the incidence of the disease ranges from 0.2 to 14 cases per 100 000, mainly caused by serogroup B strains, particularly in countries that have introduced serogroup C meningococcal conjugate vaccines.2,9 The incidence of meningococcal disease decreased by one half from 1999 to 2006 in Europe (following the introduction of serogroup C conjugate vaccines), but has subsequently stabilized.3 The burden of meningococcal disease in Asia is much less well defined, but based on limited data, most disease in Asia is caused by serogroup A and C strains.9 Serogroup B predominates in Australia and New Zealand, with incidence rates ranging between 1.4 and 7.9 cases per 100 000 and between 2.6 and 17.4 cases per 100 000, respectively, spanning the pre- and post-vaccination eras in the two regions.2,9

Limited data are available on the epidemiology of meningococcal disease in the Middle East and North Africa.10 Epidemiology in this region is affected by its proximity to the African meningitis belt and by the Hajj and Umrah mass gatherings as key factors influencing outbreaks and transmission. Whilst serogroup A remains the main cause of meningococcal disease in the region, cases of serogroup B, W135, and Y infections have increasingly been reported over the last two decades in some countries.9,10 In the Gulf Cooperation Council States, the limited available data show reported incidence rates of below 2 cases per 100 000 in Bahrain, Oman, UAE, Kuwait, and Qatar, with the exception of a few higher rates in the 1980s.10,14 In Kuwait there were 157 cases of the disease between 1997 and 2009, most of which were caused by serogroups B and W135 (43.0% and 22.1%, respectively), but also serogroups A, C, X, Y, and Z.10,14 A total of 47 cases of meningococcal disease were reported in Qatar between 2008 and 2010, mostly caused by serogroup W135 (38%), while 48 cases were reported in the UAE in 2008.14 Between 2001 and 2008, 45 cases of meningococcal disease were reported in Oman, a quarter of which were caused by serogroup W135. Serogroups A, B, C, and Ycaused 21%, 2%, 16%, and 9% of the cases, respectively.14,15

In Saudi Arabia, the incidence of the disease has fluctuated over time, affected by the large numbers of Muslim pilgrims from the African meningitis belt participating in Hajj and Umrah and the various outbreaks and disease preventative measures introduced in the Kingdom over the years. In 1987 the incidence rate in Saudi Arabia was 12.83 cases per 100 000,10 but following that peak it has remained relatively low. Between 1995 and 1999, the mean annual incidence was 0.20 cases per 100 000, ranging from 0.25 cases per 100 000 in 1995 to 0.06 cases per 100 000 in 1999. In the two outbreak years of 2000 and 2001, the annual incidence increased to 1.42 and 1.32 cases per 100 000, respectively. In the post-epidemic period between 2002 and 2010, the mean annual incidence did not exceed 0.06 cases per 100 000, ranging from 0.21 cases per 100 000 in 2002 to 0.01 cases per 100 000 in 2010.16 Serogroups A, B, C, and W135 have been documented as causing disease in Saudi Arabia, where serogroups A and W135 are the most commonly

reported.9,10,16

3. Meningococcal disease during Hajj and Umrah

Hajj, the annual pilgrimage to Mecca, Kingdom of Saudi Arabia, is one of the largest and most geographically and ethnically diverse mass gatherings in the world.17 Every able-bodied adult Muslim who can afford to do so is required to make Hajj at least once in his or her lifetime. Hajj is performed in the 12th month of the Islamic (lunar) calendar over a few days and attracts over two million Muslims from more than 183 countries to the Kingdom each year.18 Mecca is also the setting for a relatively smaller ritual called Umrah, performed year-round. It involves different rituals to Hajj and is performed in a shorter period of time. Improved international travel has rendered Umrah very congested, especially in the 3 months preceding the Hajj when the number of pilgrims rivals that of Hajj.17 Although not an essential part of the Hajj or Umrah, many pilgrims also travel to Medina, north of Mecca, as part of their pilgrimage. Extended stays at holy sites, especially during Hajj, along with physical exhaustion, extreme heat, and crowded accommodation, facilitates disease transmission during these mass gatherings, including meningococcal disease.17,18

4. Meningococcal disease before 1990

Before 1990, meningococcal disease cases during Hajj and Umrah were not uncommon given the demographics of pilgrims and their interaction during these events. However, given the global nature of these mass gatherings, they can be the scene of large outbreaks of the disease with significant national and international repercussions. The first reported international meningococcal disease outbreak following the Hajj was caused by N. meningitidis serogroup A and occurred in 1987.19 The epidemic emphasized the potentially high risk of transmission of N. meningitidis during the event. Pilgrimage-associated outbreaks of meningococcal disease also occurred in earlier years, but were less well documented.20

It is believed that N. meningitidis belonging to the III-1 clonal complex responsible for epidemics in Nepal, China, Europe, and possibly India in the 1980s, was introduced into Mecca by South Asian pilgrims attending the Hajj in 1987.19 Hajjis who became meningococcal carriers during their stay in Mecca further disseminated this strain to both developed and developing countries around the world on their return home.19,21 Outbreaks were first noted among South Asian pilgrims (from Pakistan, India, Nepal, and Bangladesh), who comprised approximately 10% of the pilgrims that year and had the highest attack rate during the epidemic.19,21,22 The disease rapidly spread among pilgrims of other nationalities and the indigenous Saudi population. The attack rate was lowest among pilgrims from the meningitis belt of

Sub-Saharan Africa who were required to be vaccinated against meningococcal disease before their arrival at Mecca.22

In 1987, 1841 confirmed cases of meningococcal disease were reported in Saudi Arabia, predominantly in the three cities most closely associated with pilgrimage (Mecca, Medina, and Jeddah).20 Internationally, soon after the 1987 pilgrimage, group A meningococcal disease was reported from neighboring Gulf countries and among Hajjis returning to Europe and North America.19 In the UK, approximately 10 000 pilgrims travelled to Saudi Arabia in 1987. There were 19 reported cases of serogroup A disease among the pilgrims returning from Mecca, and 15 subsequent cases among Muslims over the following 19 months.23 All the primary cases were adults, but the 15 secondary cases were mainly children who had had some family contact with relatives who had returned from the Hajj.22,23 In France, Denamur and colleagues observed four cases of group A meningococcal disease in the city of Amiens in the 2 months following the 1987 Hajj.24 The cases were two children, the mother of one of the children, and a 16-year-old adolescent. All cases were contacts of pilgrims returning from Hajj.

In 1988 there was a smaller meningococcal serogroup A outbreak of 305 confirmed cases in Saudi Arabia.20 However, in the same year, about 7500 cases of group A meningococcal disease occurred in Chad and a similar epidemic occurred in Sudan with approximately 18 000 cases reported.19,25 These epidemics may have been due to the introduction of the 111-1 clonal complex into Sub-Saharan Africa in 1987, as it was not found in earlier isolate surveys from Africa.26 The introduction of this clonal group may have interrupted the cyclical pattern of group A meningococcal disease in the region.19 The 1987 outbreak prompted the Saudi authorities to implement compulsory vaccination policy with bivalent A/C vaccine for all pilgrims coming to Mecca.22 As a consequence, and due to other concerted efforts by the Saudi authorities, a marked decrease in the number of meningococcal-related illnesses was observed after 1988.27,28

5. Meningococcal disease in the 1990s

During the early 1990s, two outbreaks of meningococcal disease were associated with the 1992 Umrah and Ramadan seasons and occurred among residents and Umrah visitors in Mecca and Jeddah.20,29 The outbreak strain was serogroup A of the 111-1 clonal complex that caused the 1987 and 1988 outbreaks. During March and April 1992, 102 bacteriologically confirmed cases and 80 suspected cases of the disease were identified in Mecca. Religious visitors comprised 59% of the confirmed cases and 24% of the suspected cases. The overall case fatality rate for confirmed cases was 14.7%, but reached 26.7% among pilgrims from Pakistan.20 During the same period, there were 41 bacterio-logically confirmed cases of the disease in Jeddah, with 32% of these being religious visitors and a case fatality rate among confirmed cases of 19.5%.29 Mass vaccination with a bivalent A/C polysaccharide vaccine was implemented in both Mecca and Jeddah, which quelled the outbreaks.20,29 Although these outbreaks were not known to have spread beyond Saudi Arabia,20 they were linked to a subsequent epidemic that occurred in Zambia, Central Africa, during a 2-year period from April 1992 to May 1994.22

There were small outbreaks of meningococcal disease in Mecca and Jeddah with mainly N. meningitidis serogroup A and serogroup W135 between 1993 and 199 6.28 In 1997, during the lunar month of Ramadan in the Umrah season, an increase in the number of cases of serogroup A disease was noted by the Saudi health authorities. A total of 72 cases of meningococcal disease, predominantly serogroup A, were reported.30 1n Mecca, there were 53 bacteriologically confirmed cases with a case fatality rate of 30.2%. Over 70% of the cases were religious visitors.28

In general, between 1988 and 1997 there were 483 cases of meningococcal disease in Mecca with a case fatality rate of 16.8%. Serogroup A caused most of the cases (89.2%), while serogroups W135, C, and B caused 6.4%, 3.3%, and 1% of the cases, respectively.28 Of the 483 cases, 55.7% were religious visitors who had more than double the case fatality rate of Mecca residents.28 By 1999 there was no evidence of epidemic meningococcal disease in Saudi Arabia.27

6. Meningococcal disease in the year 2000 and beyond

At the start of the 2000s there was a shift in the epidemic pattern of meningococcal disease during Hajj, with a predominance of N. meningitidis serogroup W135. During March 2000, an increase in the number of cases of meningococcal disease in Saudi Arabia was reported that coincided with the Hajj pilgrimage. Cases from Mecca and Medina during Hajj accounted for 49% of all notified annual meningococcal invasive disease cases in the Kingdom that year.16 The outbreak included 253 cases in Saudi Arabia (more than one-third were serogroup W135 and less than a quarter were serogroup A) with sustained community transmis-

sion.30

Approximately 1.7 million Muslim pilgrims originating from around the world (1.3 million from outside Saudi Arabia) attended the 2000 Hajj. Shortly after the event, by August 2000, more than 400 serogroup W135 disease cases were reported in Hajj pilgrims and their close contacts in 16 countries (the UK, Belgium, the USA, France, Morocco, Kuwait, Saudi Arabia, Oman, 1ndonesia, Singapore, Denmark, Finland, Sweden, Norway, Germany, and the Netherlands), making this the largest recorded outbreak of meningococcal disease caused by serogroup W135.30,31 The outbreak had a high fatality with a case fatality rate of 26-28% in Saudi Arabia, 11-21% in Oman, and up to 60% among patients admitted to a Mecca hospital.10,30

The 2000 Hajj-associated outbreak strain was a W135:2a:P1.5,2 strain of N. meningitidis belonging to the hypervirulent electro-phoretic type ET-37 complex and to the sequence type ST11. The origin of the outbreak strain was of interest, as up to then, serogroup W135 was associated with only 1-8% of cases of sporadic meningococcal disease worldwide and was considered to have low potential to cause invasive disease or outbreaks.31,32 Hence, Mayer and colleagues elucidated the origin of the strain linked to the 2000 outbreak by investigating 26 outbreak-associated W135 isolates and 50 W135 isolates collected worldwide between 1970 and 2000.31 They reported that the 2000 W135 outbreak was not caused by the emergence of a new W135 strain, but rather the expansion of an ET-37 clone. Members of the clone have been circulating at least since 1970 and were associated with the Hajj as early as 1996. Strains most closely related to those causing the 2000 outbreak were isolated from Algeria, Mali, and Gambia in the 1990s.31

In 2001, an additional Hajj-related outbreak of W135 meningococcal disease occurred. From February 9 to March 22, 2001, Saudi Arabian health officials reported over 109 cases of meningococcal meningitis including 35 deaths.33 Of these, more than 50% were due to N. meningitidis serogroup W135.8 The cases from Mecca and Medina during the 2001 Hajj accounted for 31% of all notified annual meningococcal disease cases in the Kingdom that year.16 The outbreak spread internationally through pilgrims, with cases identified among Hajj pilgrims and their close contacts globally, including countries in the European Union, Africa, and

Asia.5,33

By May 2001, quadrivalent meningococcal vaccination became a mandatory visa requirement for all pilgrims from any country; no meningococcal outbreak was reported in Saudi Arabia during the 2002 Hajj. Nevertheless, in the same year there was a major

serogroup W135 epidemic that affected several countries in the African meningitis belt as a result of the spread of the Hajj outbreak clone from pilgrims to close contacts.10 Due to the strict implementation of the quadrivalent vaccine to all local and international pilgrims, as well as antibiotic prophylaxis for pilgrims from the African meningitis belt, there have been no major meningococcal disease outbreaks in the Kingdom related to Hajj or Umrah since 2001. In fact, between the years 2002 and 2011, there were only 184 laboratory-confirmed cases of meningococcal disease in the Kingdom (Table 1), only 9% of which were among visa-holding Hajj or Umrah pilgrims.16 During this period, the mean annual percentage of all cases reported from Mecca and Medina was 8.1%, compared to 49% during the year 2000 and 31% during the year 2001.16 In the period between 2012 and 2015 there were only 14 cases of laboratory-confirmed meningococcal disease in the Kingdom, all of which were outside Mecca and outside the Hajj season. In Mecca, there have been no reported meningococcal disease cases since 2006 (Table 1).

7. Concluding remarks

Meningococcal disease remains a major public health threat with a fluid epidemiology and causes significant morbidity and mortality worldwide. Mass gatherings such as Hajj and Umrah are fertile grounds for the transmission and spread of meningococcal disease if appropriate preventative measures are not in place. The epidemiology of meningococcal disease in Saudi Arabia is affected by the millions of pilgrims visiting the country annually for Hajj and Umrah, a sizable proportion of whom originate from the African meningitis belt. These mass gathering events also have the potential to impact the global epidemiology of the disease by

Table 1

Laboratory-confirmed cases of meningococcal disease in the Kingdom of Saudi Arabia (KSA) and the Mecca region (1987-2015)

Year No. of cases Main No. of cases Main

in KSA serogroup(s) in KSA in Meccaa serogroup(s) in Mecca

1987b 1841 NA NA -

1988b 305 NA 176 A

1989 NA - 43 A

1990 NA - 35 A

1991 NA - 7 A

1992b NA - 102 A

1993 NA - 15 A

1994 NA - 16 A

1995 58 A 23 A

1996 37 A, W135 13 W135, A

1997b 108 A, W135 53 A

1998 42 B 23 B

1999 20 A 5 A, W135

2000b 338 W135, A 173 W135, A

2001b 316 W135 117 W135

2002 55 W135 9 W135

2003 44 A, W135 7 A, W135

2004 10 A 2 A

2005 18 W135, A 1 W135

2006 22 W135, B 0 -

2007 13 W135, A 0 -

2008 7 A 0 -

2009 6 W135 0 -

2010 3 ND 0 -

2011 6 A 0 -

2012 4 A, W135 0 -

2013 2 B, W135 0 -

2014 4 Y 0 -

2015 4 W135 0 -

NA; not available, ND; not determined. a All cases including pilgrims and non-pilgrims. b Years of the main meningococcal disease outbreaks.

introducing new serogroups to other regions of the world via returning carrier pilgrims and causing international outbreaks.

Meningococcal disease cases during Hajj and Umrah were not uncommon before the implementation of strict preventative measures by the Saudi health authorities. International Hajj-related outbreaks were documented in 1987 caused by serogroup A and 2000 and 2001 due to serogroup W135. Local Hajj- and Umrah-related outbreaks also occurred during this period, mainly due to serogroup A. In recent years no pilgrimage-associated meningococcal disease outbreaks have occurred. This is mainly due to the significant efforts the Kingdom has invested in the prevention and control of the disease during Hajj and Umrah, including strict vaccination and chemoprophylaxis policies.

Currently, all pilgrims, domestic and international, as well as local residents of the holy cities and workers in contact with pilgrims are required to be vaccinated with the quadrivalent meningococcal (ACYW) vaccine. In addition, antibiotic prophylaxis is administered at ports of entry for visitors coming from countries of the African meningitis belt, namely Benin, Burkina Faso, Cameroon, Chad, Central African Republic, Cote d'lvoire, Eritrea, Ethiopia, Gambia, Guinea, Guinea-Bissau, Mali, Niger, Nigeria, Senegal, South Sudan, and Sudan.34 The Saudi health authorities ensure adherence to these measures by examining vaccination documents at ports of entry to the Kingdom for all pilgrims. Those unvaccinated are given antibiotic chemoprophylaxis. The Kingdom has also invested in a sophisticated surveillance system for meningococcal disease, which is specifically enhanced during Hajj for the early detection and rapid response to any cases of the disease during the pilgrimage.

Notwithstanding the above, the threat of meningococcal disease outbreaks during Hajj and Umrah is ever-present. This is due to the constant importation, mixing and transmission of various serogroups between pilgrims during the events and the fact that the currently recommended vaccines do not cover all serogroups that can potentially cause invasive disease. There is therefore a potential for a sudden change in epidemiology of meningococcal disease during the pilgrimages and for local and international outbreaks to occur. For instance, outbreaks due to serogroups B or X are particularly concerning. Serogroup B N. meningitidis is regularly isolated from asymptomatic Hajj and Umrah pilgrims,35-37 and many countries with large Muslim populations have been experiencing trends of increasing ser-ogroup B meningococcal disease.38 Similarly, serogroup X N. meningitidis, for which no vaccine is currently available, has been isolated from asymptomatic Hajj pilgrims.39,40 This serogroup has been causing localized outbreaks in a number of African countries such as Niger, Uganda, Kenya, Togo, Ghana, and Burkina Faso,2,3 some of which participate in Hajj and Umrah.

Reinforcing, strengthening, refining, and updating the menin-gococcal preventative measures taking into account data on the epidemiology of the disease and available preventative tools are needed. Preventative strategies that impact carriage and transmission should be implemented. Although they prevent invasive disease, polysaccharide vaccines currently used have a short protective response and do not prevent the carriage or transmission of N. meningitidis.3,4 Conjugate meningococcal vaccines are available and quadrivalent ACYW conjugate vaccines have been licensed since 2005. ln addition to preventing invasive disease, the conjugate vaccines have the added value of reducing transmission by preventing or clearing carriage.3,8,12 The conjugate quadrivalent vaccine should be recommended for the prevention of meningo-coccal disease during Hajj and Umrah, taking into account its effectiveness, availability, and cost, especially for low-income countries from which most pilgrims originate.8

lf the quadrivalent conjugate vaccine is used and shown to be effective in reducing carriage, with the same associated herd

SSS86; No. f Page, 5

immunity effect as that experienced with the conjugate C vaccine,41 there may no longer be a need for the costly and potentially problematic chemoprophylaxis policy for pilgrims. New serogroup B vaccines are also available and may be used in times of outbreaks, as has been done in other countries.42 Surveillance and tracking of carrier state and the occurrence of invasive meningococcal disease among pilgrims and the disease epidemiology in their countries of origin are important to guide interventions to prevent disease and predict and prepare for potential outbreaks. Early detection of meningococcal disease cases during Hajj or Umrah pilgrimages through an effective and responsive surveillance system should continue to prevent and control any outbreaks.

Conflict of interest: None to declare.

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