Department of Laboratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
Örebro University Hospital. Örebro University, School of Medical Sciences. Department of Laboratory Medicine.
National Reference Centre for Meningococci and Haemophilus influenzae, Institute for Hygiene and Microbiology, Julius-Maximilians University, Wuerzburg, Germany.
Department of Medical Microbiology and Infection Prevention, Netherlands Reference Laboratory for Bacterial Meningitis, Amsterdam UMC location AMC, Amsterdam, the Netherlands.
National Reference Laboratory for Neisseria Meningitidis, Department of Infectious Diseases, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal.
National Reference Laboratory for Neisseria Meningitidis, Department of Infectious Diseases, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal.
Vaccine Preventable Bacterial Diseases, Science, Reference and Surveillance Directorate, National Microbiology Laboratory Branch, Public Health Agency of Canada, Winnipeg, Canada.
Norwegian Institute of Public Health, Oslo, Norway.
Department Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy.
Department Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy.
National Meningitis Reference Laboratory, Laboratory for Surveillance of Infectious Diseases, Department of Public Health Policy, School of Public Health, University of West Attica, Athens, Greece.
Meningococcal Reference Unit, UK Health Security Agency, Manchester Royal Infirmary, Manchester, UK.
Immunisation and Countermeasures Division, UK Health Security Agency, Colindale, London, UK.
Meningococcal Reference Unit, UK Health Security Agency, Manchester Royal Infirmary, Manchester, UK.
Immunisation and Countermeasures Division, UK Health Security Agency, Colindale, London, UK.
Immunisation and Countermeasures Division, UK Health Security Agency, Colindale, London, UK.
Meningococcal Reference Unit, UK Health Security Agency, Manchester Royal Infirmary, Manchester, UK.
Meningococcal Reference Unit, UK Health Security Agency, Manchester Royal Infirmary, Manchester, UK.
Meningococcal Reference Unit, UK Health Security Agency, Manchester Royal Infirmary, Manchester, UK.
National Reference Centre for Meningococci and Haemophilus influenzae, Institute for Hygiene and Microbiology, Julius-Maximilians University, Wuerzburg, Germany.
Great Hill Solutions, Chantilly, USA.
Great Hill Solutions, Chantilly, USA.
Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, CDC, Atlanta, USA.
Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, CDC, Atlanta, USA.
Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, CDC, Atlanta, USA.
Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, CDC, Atlanta, USA.
Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, CDC, Atlanta, USA.
Immunisation and Countermeasures Division, UK Health Security Agency, Colindale, London, UK; Centre for Neonatal and Paediatric Infections, St. George's University of London, London, UK.
Invasive Bacterial Infections Unit and National Reference Centre for Meningococci and Haemophilus influenzae, Institut Pasteur, Université Paris Cité, Paris, France.
Meningococcal Reference Unit, UK Health Security Agency, Manchester Royal Infirmary, Manchester, UK.
OBJECTIVES: Collectively, the Hajj and Umrah pilgrimages draw >30 million pilgrims to the Kingdom of Saudi Arabia (KSA) each year. Before Hajj 2024 (14 to 19 June), the meningococcal serogroup W ST-11 complex (W:cc11) Hajj-strain sublineage caused multiple international cases of invasive meningococcal disease (IMD) associated with travel to the Middle East and Asia. Here we identify the strains responsible.
METHODS: All Hajj strain sublineage genomes on PubMLST.org underwent core genome MLST comparisons (PubMLST.org).
RESULTS: Isolates from 30 cases, across seven countries, formed five phylogenetic clusters within two distinct strains. Travel histories included KSA, other Middle Eastern countries, India, Mauritius, via Turkey, and no known associated travel. The prevalent strain, representing four clusters, had no African, and limited Middle Eastern, representation. The geo-temporal distribution of available genomes suggested Eastern Europe as a possible source.
CONCLUSIONS: The rapid expansion of Umrah/travel-related W:cc11 IMD cases in early 2024 was due to multiple strains/sublineages. Despite the involvement of non-KSA travel-destinations, the coincidence of cases with the busy month of Ramadan, and the abrupt cessation during Hajj (when vaccine compliance is maximal), suggest that Umrah was a key driver and highlight the need to reinforce mandatory vaccination whilst maintaining global vigilance.
Elsevier, 2025. Vol. 91, no 4, article id 106558
Hajj, Hajj strain sublineage, Meningococcal serogroup W, Outbreak, ST-11 clonal complex, Umrah