Meningococcal W135 carriage; enhanced surveillance amongst east London Muslim pilgrims and their household contacts before and after attending the 2002 Hajj

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.

Surveillance of Australian Hajj pilgrims for carriage of potentially pathogenic bacteria: Data from two pilot studies

AIM

To estimate the pharyngeal carriage rate of Neisseria meningitidis (N. meningitidis), Streptococcus pneumoniae (S. pneumoniae) and Staphylococcus aureus (S. aureus) among Australian Hajj pilgrims.

METHODS

In 2014, surveillance was conducted in two phases among Australian Hajj pilgrims: The first phase during Hajj in Mina, and the second phase soon after returning home to Australia. Nasopharyngeal or oropharyngeal swabs were taken from participants then tested, firstly by nucleic acid testing, and also by standard culture.

RESULTS

Of 183 participants recruited in the first phase, 26 (14.2%) tested positive for S. pneumoniae; 4 had received pneumococcal conjugate vaccine (PCV13). Only one tested positive for N. meningitidis (W). Of 93 2^nd phase samples cultured, 17 (18.3%) grew S. aureus, all methicillin sensitive, 2 (2.2%) grew N. meningitidis (on subculture; one serotype B, one negative), and 1 (1%), from an unvaccinated pilgrim, grew S. pneumoniae.

CONCLUSION

Relatively high carriage of S. pneumoniae and little meningococcal carriage was found. This indicates the importance of a larger study for improved infection surveillance and possible vaccine evaluation.

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.